Second Edition
RLBijlaniMD, SM, FAMSFormer Professor and Head Department of Physiology All India Institute of Medical SciencesNew Delhi
Jitendar P Vij
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Nutrition: A Practical Approach
© 2007, Jaypee Brothers Medical Publishers
All rights reserved. No part of this publication should be reproduced, stored in a retrieval system, or transmitted in any form or by any means: electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the author and the publisher.
First Edition : 1992
Second Edition : 2007
9788184481129
Typeset at JPBMP typesetting unit
Printed at Paras
_FM5ToMY STUDENTS
who have borne the brunt of experimental
_FM7Foreword to the First EditionALL INDIA INSTITUTE OF MEDICAL SCIENCES
DEPARTMENT OF PATHOLOGY
ANSARI NAGAR, NEW DELHI-110026
TEL: 2652352, 686-2435, 2661123/376
FAX: 26862435
TELEX NO.: 31-73042 AIIMS
There is no dearth of books on nutrition, basic and applied, so that one might be tempted to exclaim “Yet Another Book” ! However, a perusal of Nutrition: A Practical Approach by RL Bijlani at once belies such a fear for it is a somewhat unusual and rather a unique book. We know that a hiatus exists today between patients' interest and inquisitiveness about what diet to have and what foods to avoid for their particular illnesses and the somewhat evasive responses often given by physicians reflecting their ignorance. This is an area where practitioners of indigenous systems of medicine score over their modern counterparts. Medical curricula do provide physiological knowledge about food and nutrition and about pathological syndromes, but are reticent about what practical advice and instructions to give regarding diet for the individual patient.
The book contains what every graduating physician should know, whether he or she is destined for general practice or a specialist career. It is targetted to medical students although it should interest wider groups. It is written in simple, direct and colloquial style, yet the messages are based on scientifically sound and uptodate knowledge. Presented in the form of a series of exercises, it is intensely practical with _FM8added material to facilitate tape-slide programmes for small groups and self learning. RL Bijlani, from past publications, indeed even from his student days, has a rare gift of effective communication of science which is the high point of this work. He makes some simple and direct points, such as improving the diet does not necessarily involve additional expense, use locally available foods, cereal-pulse mixtures can readily satisfy energy and protein needs and with added fruits and vegetables will also meet vitamin and fibre needs, cholesterol is not a poison but a normal essential constituent of the body. Topics which interest and worry people and about which there is so much popular lore, but to which the medical profession pays scant attention also figure in this work. Topics such as constipation, belching and flatulence are addressed, and their physiological bases presented with practical advice as to how to cope with them.
In sum, this book is a valuable addition to the practice of medicine and nutrition.
(V RAMALINGASWAMI)
PROFESSOR-EMERITUS
New Delhi
7th January, 1992
_FM9Preface to the Second EditionIt is more than twelve years since this book was first published. During this period, the science of nutrition has grown and evolved, but there has hardly been any change in whatever little medical students learn about the subject. The emphasis is still on the biochemical aspects of nutrition, while the knowledge and skills required for translating chemical knowledge into foodbased recommendations continue to be neglected. This fact was highlighted also during the workshop on nutrition in the medical curriculum organized in April 2004 by the renowned nutrition scientist, Dr C Gopalan. It is hoped that the recommendations of the workshop will lead to some desirable changes in the medical curriculum: till then one can only hope that doctors will make up the deficit by self-learning.
In keeping with the need which this book is designed to fulfill, the reader has been introduced in this edition to Food Based Dietary Guidelines published by the National Institute of Nutrition in 1998. Besides this, the sections dealing with dietary fats have been rewritten in light of new knowledge, specially that regarding the need for n-3 polyunsaturated fats. The concept of dietary fibre has been expanded to include other phytonutrients. The classifications of obesity and lifestyles have been revised in light of the latest literature. With these changes, the book should be a source of uptodate information on nutrition for medical students and practicing physicians.
Readers are requested to send their comments and suggestions so that the next edition can be improved further.
RL Bijlani
New Delhi
_FM11Preface to the First EditionThis book has evolved from an exercise which I devised for first year medical students at the All India Institute of Medical Sciences about ten years ago. The exercise was a conscious effort to fill a gap in medical education. While medical students get glimpses of the science of nutrition at various stages of their course, they learn very little about translating their scientific knowledge into practical terms. As a result, doctors often tell their patients to take a high protein or low salt diet, but fumble for words when asked which foods to take, and which to avoid. Further, doctors often reinforce the misconceptions of patients by telling them to consume meat, eggs, milk and cheese for a high protein diet. The reality, in fact, is that cereals and pulses are the major sources of protein in an Indian diet, and there is hardly any situation, in health or disease, where we need more protein than what can be supplied by a judicious mixture of cereals and pulses. One way to remedy the ignorance of doctors in this area of everyday importance is to include a few exercises in the medical curriculum which involve delving into facts and figures. While it is neither possible nor necessary to remember all such facts and figures, this book will give the students a feel of foods in scientific terms, and more importantly, tell them where to look for information when required. At present I find that much of the valuable work done at the National Institute of Nutrition which is easily available for ready reference in Indian Council of Medical Research publications, remains unknown to medical students and doctors.
One may ponder whether it is justified to increase the burden of the already overburdened medical student. While it is true that medical sciences are growing at a phenomenal rate, it is also a fact that a careful evaluation of the medical curriculum reveals considerable redundancy. There are many parts of the _FM12curriculum which are relatively irrelevant to the needs of a doctor. A continuous review involving appropriate additions and deletions is an integral part of any healthy system of education. I would not deny that I have met with some resistance from my own students while administering these exercises. A common question is whether all this is not ‘the job of a dietitian’. First, a dietitian is available only in large hospitals. Small hospitals and practitioner's clinics do not have dietitians but treat a large number of patients needing dietary advice. Second, even at places where a dietitian is available, the patient develops greater confidence in the dietitian's advice if it is reinforced by the doctor. Finally, since the doctor is the leader of the health care team, even when the dietitian has a doubt, she may turn to the doctor for clarification. All these reasons are quite analogous to those for which a medical student is taught how to do routine tests on a blood or urine sample although doing the tests is ‘the job of a technician.’
Since this is an unconventional book, both in content and style, readers' comments would be specially welcome, and are sincerely invited.
I am grateful to Prof V Ramalingaswami, a nutrition expert of international repute, for his valuable comments on the manuscript, and for writing a generous foreword to the book. I would like to thank Dr NK Arora, Dr Anupa Siddhu, Ms Rekha Sharma and Ms Shobha Gupta for helpful discussions and useful information, and Ms Jatinder Kaur for typing the manuscript. Ms Jigeesha Pasricha has given a touch of humour to the work with her cartoons, and Ms Punita Puri has done the computer graphics. Dr KP Kochhar and Ms Promila Kapoor shared the drudgery of proofreading cheerfully and efficiently. My wife, Lovleen, provided the vital link between knowledge and practice which is crucial for a book on applied nutrition. Finally, it is the publishers who have made the book possible. Mr JP Vij promptly accepted the challenge and risk involved in this unconventional venture.
RL BIJLANI
New Delhi
How to Use This BookThis book can be used in at least two ways.
1. As the script for a tape slide program
The teachers can use the book to prepare a set of tape slide programs. The ‘text’ section of the book has been written in a conversational style, all ready for the teacher to record on a tape. However, the teacher is free to make any changes in the script to suit his or her taste or local conditions. The audio tape would need the visual aid of corresponding slides to form the complete learning resource materal. The material for slides has also been given in the book in a camera-ready form. Once the audiotape and slides are ready, the exercises may be conducted by the teacher during practical classes. The teacher's role would be primarily limited to organisation and answering students' questions.
There are two reasons why it is better to do these exercises during the practicals. First, the tape slide program is ideally a small group activity, and for practicals the students are usually grouped into small batches. Second, the exercises need a few hours at a stretch, and that much time is usually available only in practical classes.
The tape and the corresponding set of slides can be issued to small groups of students for a limited period of time to be used as self-learning material.
2. As a conventional book
The book can be used directly for learning. Read the ‘text’ and see the corresponding ‘slide’ for a fuller understanding. Stop to make calculations or comments as indicated. Further, while revising the material, looking at only the ‘slides’ can save a lot of time.
This is the way the book is likely to be used most frequently. However, since the book is also meant to be suitable as the script for tape slide programs, the figures have been referred to as slides. While reading this book the student should consider ‘slides’ to be synonymous with figures. He/She should use the ‘slides’ as visual aids the way he/she uses figures in other books. Some portions of the text which are relevant only to the script of a tape slide program have been presented in small print. The student may ignore these portions while using this book like a conventional one.
The book can serve as self-learning material, more or less like a programmed text, with the added advantage that the language is conversational rather than formal. While reading the ‘text’, the student can imagine as if the teacher is talking to him/her. What a wonderful way for self-learning: very similar to what Eklavya did. For using the book in this way, neither the teacher nor any equipment is necessary. It can be used like this by anyone — a student, a teacher, a dietitian, or a practitioner. All what is required is investment of a little time in something that is likely to be useful everyday — in the profession, and outside it.
1.1 Food composition and nutrient requirements are dull subjects, full of figures which are so difficult to remember. You might be relieved to know that you need not remember any figures—they are readily available in easily accessible publications.
1.2 What you need to do is to use the figures to solve some everyday problems. If you solve such problems often enough, the figures which you use most frequently will eventually become a part of your awareness without your having made any effort to remember them. Whether you will be actually offering dietary advice on an everyday basis is not important; what is important at this stage is that you should gain acquaintance with some exercises of the type presented here. The acquaintance would be valuable to you in your future work as a doctor.
1.3 If you happen to run a small clinic, you might have to do many such exercises for your diabetic or obese patients.
1.4 If you join a big organization you may have a dietitian available to help you, but you can make good use of her expertise only if you are well acquainted with the subject yourself. Further, wheneverthe dietitian runs into some difficulty, she may turn to you for guidance. Then if you cannot solve the problem, you would cut a sorry figure.
1.5 That sort of predicament is an occupational hazard for doctors. There would be lots of things that you may have never been taught, or you have forgotten through prolonged disuse. But whenever anyone in the hospital has any problem, you, as the leader of the health care team, will be approached for guidance. Therefore, although you may choose to be master of only one, it will pay you in the long run if you are also the Jack of all. If you succeed in learning anything even remotely related to the medical profession, one day you will thank your stars for it.
1.6 This exercise will tell you how to calculate the composition and energy content of a given diet; that is, if you know what you or your patient eats, you should be able to tell how much protein or fat it contains, and how many Calories it provides. This information is basic for scientific evaluation of the diet.
1.7 The calculation involves four basic steps. First, list every item of the diet. It is customary to evaluate a day's intake at a time. Hence, write down every item of the diet consumed during the day.
1.8 Second, break up each item into its major ingredients. The tables on food composition generally list only the ingredients. Hence find out the ingredients of each item consumed, and the weight of each ingredient that went into the portion consumed.
1.9 Third, find the composition and energy content of every ingredient used. The bible for this information is Nutritive Value of Indian Foods published by the National Institute of Nutrition, an ICMR institute in Hyderabad. Published tables will give you the composition and energy content per 100 g of the edible portion of a food. From this information, you can easily calculate the corresponding values for any weight of the food.
1.10 Fourth, calculate the individual nutrient content of the quantities of ingredients actually consumed. Now you simply have to add up the individual nutrient content of the ingredients to get the total intake of these nutrients.
1.11 To recapitulate, the four steps are: First, list every item. Second, break the items into their ingredients. Third, find the nutritive value of each ingredient from the published tables. And finally, add up the individual values to get the nutrient composition and energy content of all the items listed.8
1.12 Let us apply this knowledge to determine the nutrient composition and energy content of just one meal.
1.3 The first step, as we have learnt, is to list every item.
The meal consists of two chapaties, one helping of rice, and one serving each of dal, vegetable and curd.
1.14 The next step is to break these items into ingredients.
Each chapati has 25 g wheat and 2 g cooking medium, which is a vegetable oil. One helping of rice consists of 50 g rice cooked in 5 g of the medium. The serving of dal has 50 g of the dry dal which has been cooked using 2 g of the cooking medium. The vegetable has equal quantities of potato and beans. One serving has 50 g of each, and 5 g of the cooking medium. The portion of curd consumed “ at the meal weighs 200 g.
1.15 The next step is to find the published nutrient value of ingredients.
We need the nutrient value of wheat, rice, green gram, potato, green beans, curd and the cooking medium.
Before we consult the Tables for these values, you may like to draw on a piece of paper columns of the type shown in the next slide.1
_________
1.16 Take a large piece of paper to draw these columns.
1.17 Here are the values you need.
As you can see for yourself, if you know the carbohydrate, protein and fat content of a food, you can easily calculate its energy content. Carbohydrates and proteins provide 4 Calories2 per gram each, while fats provide 9 Calories per gram. Thus the energy content of wheat flour will be 12.1 multiplied by 4, plusl .7 multiplied by 9, plus 69.4 multiplied by 4.
_________
2 The unit of energy commonly used in nutrition is kilocalorie. In this book, kiloCalories have been denoted as Calories (spelt witha capital C) in the‘text’ in keeping with its conversational style. In the ‘slides’ the unit has been abbreviated as kcal. For therelationship between Calories and joules, see Appendix 2.
1.8 Finally, the last step is to calculate the food value of the meal. You will find the table you have drawn handy.
The exercise is so simple that you should switch off the tape recorder, go back to do the previous slide and settle down to do some simple mathematics.
A calculator will improve your efficiency, but is not essential.
1.19 If you are through with the exercise, you may confirm your results by having a look at the next few slides.
1.20 Here are the calculations for the chapaties.
1.21 Here are the calculations for rice and dal.
1.22 Here are the calculations for vegetable and curd.
1.23 Here is the composition and energy content of the meal. As you would understand, the figures are the result of adding the values obtained in the previous three slides.
1.24 The vitamin, mineral or dietary fibre content of a meal can be calculated along the same lines. If you find the nutritive value of all the meals consumed during a day, you can derive from them the corresponding values for the whole day's intake.
1.25 Calculation of nutrient composition and energy content of a diet by the method illustrated above is simple, logical and accurate but time consuming. For quick calculation, one may make use of ‘food exchanges’. Food exchange system is based on the principle that foods with similar nutrient composition have been grouped together, and the approximate nutrient content of one helping or unit serving worked out in advance.
1.26 Carbohydrate-rich foods are included in the cereal exchange. The wheat content of one chapatie (20 g) is taken as a unit, and equivalent amounts of other carbohydrate rich foods listed. One unit of each food in the exchange gives approximately 15 g carbohydrates, 2 g protein and 70 Calories. Some examples of one cereal exchange include one chapatie, one large slice of bread, 3 tablespoonfuls of rice, one medium-sized idli, 3 tablespoonfuls of corn flakes, or 3 to 5 biscuits, depending on the size. What it means is that these portions of these foods are, nutritionally speaking, roughly equivalent.15
1.27 High-protein grains, the pulses, are included in the legume exchange. Each unit of legume exchange provides 15 g carbohydrate, 6 g protein and 85 Calories. 25 g of almost any legume constitutes one unit in this exchange.
1.28 Vegetables are rather heterogeneous in their composition. Therefore, they have been grouped into at least two exchanges. Group A includes green leafy vegetables with high water, vitamin and mineral content, but very low calorific value. One unit in this group consists of 100 g of the vegetable, and provides only 20 Calories. These vegetables may be neglected while considering the energy content of a diet.
1.29 Group B includes other vegetables but not starchyroots and tubers. These vegetables provide a little more energy than group A vegetables.17
1.30 Starchy roots and tubers being rich in carbohydrate may be included in the cereal exchange, or treated separately.
1.31 Fruit exchange is somewhat similar to the group B vegetable exchange with two important differences. First, the protein content of fruits is negligible. Secondly, fruits being more expensive than vegetables, while framing a diet, the number of fruit exchanges suggested should depend on the 18socioeconomic status of the patient. If we feel that the patient cannot afford fruits, a balanced diet can be framed using vegetables instead of fruits, provided the patient takes part of the vegetables in the raw form.
1.32 Next we come to the milk exchange, which includes milk and milk products. This group of foods is the only one which contains significant quantities of carbohydrates, proteins as well as fats.
1.33 The meat exchange includes various animal foods including egg and cheese.
1.34 Lastly, we come to the fat exchange. As you may notice, different cooking media have the same calorific value. The main difference lies in the degree of saturation of theirfatty acid content.
1.35 Now let us examine how the exchange system can help in quick calculation of the composition and calorific value of a diet. For the sake of illustration, let us take the same meal which we discussed earlier.
As is clear, there is considerable error in using the method of exchanges. But it saves so much time that it is quite acceptable when the workload is heavy. In any case, it is well to keep in mind that in dietetics the impression of accuracy conveyed by figures is illusory. Even if the nutrient content is calculated by direct use of detailed food composition tables, inaccuracy is inevitable in real life situations because the size of the helpings actually consumed, and the ratio of ingredients in a recipe, are seldom measured or fixed. Accuracy is possible only in the laboratory, which belongs to the realm of experimental nutrition, not everyday dietetics.
1.36 Even more important than knowing something is to know how to learn it, or where to find it. In nutrition plenty of factual data is available in many easily accessible publications. But food is such a commonplace topic of conversation that you will be asked questions about it at several social gatherings. Since you can neither carry nutritional tables with you everywhere, nor can you remember them, it is good to keep some simple figures in mind all the time. The questions you will be generally asked will be of two types. One type is related to the composition of foods; for example, how much protein does soyabean contain. The other type is related to the energy content of units of foods as consumed, e.g. how many Calories does a samosa contain. If, being a doctor, you cannot answer such questions, you make a very poor impression on others. The next few slides will help you not only avoid cutting a sorry figure, but also enable you to make a meaningful contribution to such discussions.
1.37 Here is the approximate composition of a few classes of foodstuffs. Cereals have about 70% carbohydrate and about 10% protein. The remaining 20%, as you know, is water. Pulses have about 10% more protein than cereals, and correspondingly their carbohydrate content is 10% less. With these figures you can easily dispel the popular misconceptions that cereals are simply starch while pulses are full of protein. They both have a lot of starch, and also some protein. Although the protein content of pulses is more than that of cereals, the contribution of cereals to our protein intake is greater than that of pulses because we consume much more of cereals than pulses. In an Indian diet, as much as 80% of the protein intake may come from cereals. The importance of pulse protein lies not in its quantity but in its quality. Although both cereal and pulse proteins are poor in quality in comparison with animal protein, they are complementary. Cereals compensate for the methionine deficiency of pulse protein, and pulses make up the lysine deficiency of cereal protein. If our food contains about one-fifth as much pulses as the cereals, the mixture of proteins that we get is quite satisfactory in quality. Alternatively, the quality of cereal protein can be improved, of course at a much higher cost, by supplementing it with animal protein.
Soyabean is a class by itself, and its composition is unique. However, it is good to remember that it is neither indispensable, nor a miracle food. Whatever quantity of protein it provides can also be obtained from double the quantity of any other legume.
Fruits and vegetables make very little contribution to energy intake. Their main role is to provide us vitamins and minerals. The main difference between fruits and vegetables, from a nutritional point of view, is that fruits are consumed 23raw, and therefore their vitamin and mineral content is better preserved. But that does not fully justify their much higher cost. All the benefits of fruits can be obtained from vegetables provided at least a part of our daily vegetables are consumed raw, and the rest are cooked with adequate precautions to minimise vitamin and mineral loss.
Dry fruits are not a major item of the diet but a common subject of discussion. Many popular misconceptions can be cleared by knowing that nuts, in general, are high calorie foods, providing about 600 kcal per 100 g. This is due to their high fat content. In this respect, there is no difference between costly nuts such as almonds or cashewnuts, and relatively less expensive nuts such as walnuts or peanuts. Coming to finer points, the modest walnut is emerging a sort of winner because of its fat having substantial n-3 type of PUFA, which is often deficient in diets currently popular. But all the same, the basic fact remains that all nuts, including walnuts, are high calorie foods. Hence including them in the diet may necessitate excluding something else so that the energy intake does not exceed the energy expenditure. A positive energy balance will lead to obesity, which would enhance the risk for several diseases, no matter which nuts disturbed the energy balance.
1.38 Here are some expensive and prestigious items of food, none of which is indispensable. Milk contains all the three major nutrients in significant, and roughly equal, amount. That is why it is called a complete food. But it is only during the first six months of an infant's life that milk alone constitutes a satisfactory diet.
Egg is a good source of high quality protein, and because of its high fat content, also a good source of energy. It is a supplement of high nutritive value at moderate expense.
Meat is basically 20% protein of good quality. Some meats also have a significant quantity of fat.
Fats and oils are 100% fat, and sugar is 100% carbohydrate. But, for once, purity is not supreme. Foods having a mixture of nutrients are much more valuable and dependable sources of nourishment than these foods which provide just one nutrient.
Honey is a generally overrated food. It is basically a highly concentrated solution of a mixture of sugars. It also has some vitamins. But honey is not a unique source of any important nutrient.
_________
1.39 Another type of information, which should become as much a part of your awareness as your name, is the calorific value of a samosa or an orange, and so on. There is so much variation in the size of such items that any value will be highly approximate, but still a plausible guess is generally possible.
The portions of a majority of foods as commonly served provide about 100 Calories. Therefore if you have any doubt about the calorific value of a food, the safest guess to hazard is 100 Calories. However, if common sense warns you that the food in question has definitely much less or much more energy than that, take 50 Calories away from, or add 100 Calories to the norm. In this slide and the next few, you see some foods which actually provide about 100 Calories.
As you see in this slide, one unit of almost every item of the everyday diet provides about 100 Calories.
1.41 Here are some sweets and fruits providing about 100 Calories each.
1.42 Here are a few lightweights providing only about 50 Calories. Raw leafy vegetables provide so little energy that they can be consumed in almost unlimited quantity even by the calorie-conscious.
1.43 Some foods, especially fried ones, provide about 150 Calories in the quantities commonly consumed.
1.44 Some still heavier items provide about 200 Calories.
1.45 And here are the real heavy weights providing more than 200 Calories.
1.46 Now you are well equipped to make an informed contribution to a discussion on food values. You may not be able to answer all the questions—nobody really can—but you would not feel embarrassed. However, as a scientist, do not forget that there is an error involved in using even the most accurate tables. When we use exchanges or any other form of approximate information, we accept additional error for the sake of convenience.
1.47 Now you may find it interesting to calculate the composition and energy content of your own dietary intake on a typical day. For this you would have to get hold of a collection of food composition tables, perhaps the ICMR book Nutritive Value of Indian Foods, referred to earlier. You may choose the exact method, or some approximate method; or still better, both, to see how much difference it makes.3
_________
2.1 This exercise will tell you how to evaluate a given diet in scientific terms.
2.2 Evaluation of a diet in scientific terms involves three basic steps. First, calculate the composition and energy content of the diet.
2.3 Second, find the age, sex, height, weight, occupation, everyday physical activity and health status of the individual consuming it. These are the major factors which determine nutrient requirements. Hence, the nutrient intake should be assessed in terms of these factors for evaluation of the diet.30
2.4 Finally, find the recommended intake of energy, protein and other essential nutrients for the type of individual who is consuming the diet to be evaluated. The reference for the Indian population for this purpose is the ICMR book on Recommended Dietary Allowances
2.5 Let us apply these guidelines to evaluate a diet being consumed by a 30-year-old 60 kg sedentary man. In the calculation of nutritive value, include also iron, calcium, vitamin A and vitamin C content, because these are frequently marginal or deficient in our diet.31
2.6 His breakfast consists of one parontha, one omelette and a glass of milk. It would be better if you enter it, and all the other meals in a table of the type we made in the previous exercise. However, do not forget to add the columns for iron, calcium, vitamin A and vitamin C.1
2.7 His lunch consists of four chapaties, and a serving of dal, vegetable and curd. Enter these also in the table.
_________
2.8 His evening tea consists of two cheese sandwiches and a cup of tea.
2.9 His dinner consists of rice, dal, a vegetable and curd.
2.10 Here is information about the ingredients of foods con sumed. You may enter it also in the table. Do not forget to multiply the quantities where necessary. For example, although the ingredients of chapaties have been given for each chapati, our subject consumed four chapaties at lunch.
The information is continued on the next slide.
2.11 When you are through with it, move to the next slide.
2.12 Here is the nutritive value of some of the ingredients used.
The information is continued on the next slide.
2.13 Here is the nutritive value of the other ingredients.
2.14 Now, switch off the tape recorder and slide projector.
Calculate the composition and energy content of this diet. Some of the calculations you made for the previous exercise can be used here straightaway.
2.16 Use the information on this slide to comment on the quality of the diet. Write the main points in your comments on a piece of paper before you move to the next slide.
2.17 The diet is very well-planned. It is a strikingly balanced diet using simple, readily available and relatively inexpensive components. It provides bulk of the proteins in the form of a cereal-pulse mixture, and there is also a reasonable quantity of animal protein. It is reasonably adequate in all nutrients.36
2.18 The energy content of this diet is just right, the ICMR recommendation for a 60 kg sedentary man being 2425 Calories. Its protein content is also satisfactory, the ICMR recommendation being 60 g per day on the basis of 1 g per kg body weight. A reasonable excess of proteins is not going to do any harm. About 60 g per day is the minimum that should be provided; more than that, at least within reasonable limits, is known to be quite harmless. Try to find out what harm a huge excess of protein might do.
The calcium content is also satisfactory, the ICMR recommendation being 400 mg per day. In fact, we have a moderate excess, but once again it is quite harmless.
The iron content is also perfectly satisfactory, the ICMR recom mendation being 28 mg per day.
Vitamin A is quite enough; we shall see a little later how we arrived at the figure of 815 μg for the intake of vitamin A.
Vitamin C intake is barely enough. In fact, the true intake might even be deficient because of the heavy cooking losses to which vitamin C is susceptible.37
2.19 You might recollect that the carotene content of the diet is 1453 μ g. But carotene is not absorbed and utilised as efficiently as preformed vitamin A. Assuming 25% bioavailability, the carotene intake is equivalent to 363 μg of retinol. In addition, the diet also has 452 μ g of preformed vitamin A, giving a total intake of 815 μ g. The ICMR recommended dietary intake of 600 μg is about half the quantity recommended in some other countries. But perhaps the Indian recommendation is quite adequate to prevent deficiency; the likely benefits from the excess recommended in other countries are not well-established.
2.20 At this stage, it would be instructive to go back to the big table in which you calculated the composition and energy content of this diet. Have a critical look at it and you will observe that the bulk of protein comes from cereals and pulses, not from milk or milk products, not from meat, not from eggs. In fact, about 30% of the protein intake, which is about half the recommended protein intake, comes from cereals alone. This should make you aware of the importance of cereals and pulses for supplying protein and the valuable contribution which cereals make to protein intake in the common man's diet in India.
The largest fraction of calcium comes from milk and milk products—in fact these items supply about 90% of the calcium intake. Therefore, you can understand our critical dependence on milk and milk products for calcium intake. One can also visualise the poor calcium intake of those who cannot afford to take milk and milk products.
The bulk of iron, perhaps a little surprisingly, is coming from cereals. Just compare the relative contributions of wheat and rice to iron intake: in our comparison wheat is a much better source of iron. But the difference is mainly because we are comparing whole wheat flour with white polished rice. The husk of grain has most of the iron. Hence, hightly refined wheat flour, called maida, has very little iron; on the other hand, brown rice, or parboiled rice has much more iron than indicated in our tables here. The husk not only has iron, it also has a much higher vitamin and dietary fibre content than the interior of the grain. That is why whole or undermilled grains are nutritionally superior to highly refined grains.
The largest fraction of vitamin A is coming from egg milk and milk products, and carrots. Carotene containing 39vegetables are indeed very important sources of vitamin A in an Indian vegetarian diet. These vegetables can be seasonal, but the saving feature here is that excess vitamin A can be stored in the liver, and becomes available for use during lean periods.
Potatoes are pretty rich in vitamin C, and so are some green vegetables, and they are providing about three fourths of the vitamin C content of this diet. But a lot of this vitamin C might be lost through oxidation during cooking, and hence it is desirable to eat some vitamin C-rich greens in the raw form
2.21 Give one more critical look to your big table packed with figures. What is it that vegetables are really providing in the sample diet you have evaluated? As you can see, the vegetables are providing mainly vitamins and minerals. Although not included in our calculations here, vegetables and fruits also provide some dietary fibre. They cannot provide as much fibre as whole grains, but their contribution is significant because vegetable and fruit fibre is qualitatively different from grain fibre, and both types have some what distinct physiological effects. Since around 90% of most vegetables is water, they hardly provide any calories; we can consider them vitamin-mineral tonics in natural packing.40
The only lacuna in this diet is absence of raw vegetables and fruits. That is the reason why its content of some vitamins is marginal. In fact, inadequate vegetable and fruit intake is the most glaring defect of the typical Indian diet. The current food-based dietary guidelines of ICMR recommend a daily intake of 300 g of vegetables and 100 g of fruits.
If you have any more comments, please feel free to make them. If you have any questions, discuss them with the teacher.
3.1 Your knowledge of physiology or medicine gives you the scientific basis for prescribing a low calorie diet or a low salt diet to a patient. But the patient wants to know what he should have. This exercise will help you in translating the scientific specifications into a real diet.
3.2 In order to bridge the gap between chemistry and the kitchen, we must know something about the person for whom the diet is to be prescribed. Low calorie diets satisfactory for an Indian, a Chinese, and a European would be three very different diets, although scientifically each is a low calorie diet. Therefore, besides the scientific specifications, it is important to know the dietary pattern and personal likes and dislikes of the patient. A diet which does not take these basic factors into consideration is unlikely to be adopted by the patient.
3.3 Hence, translating scientific specifications into a real diet involves four basic steps. First, ask the patient what he generally eats during the day, and what his personal likes and dislikes are.
3.4 Second, using the information given by the patient and your own background knowledge about the composition of foods, frame a provisional diet which is likely to meet the scientific specifications.
3.5 Third, find the composition and energy content of the diet. This is something you have already learnt. The composition and energy content of the diet will help you judge how far the diet you have framed actually meets the scientific specifications.
3.6 Finally, make a few adjustments in the provisional diet to make it meet the specifications exactly. You may also like to talk to the patient if some more of his desires can be accommodated without any serious compromise with the scientific requirements. Now you have a diet which is satisfactory from the scientific point of view as well as convenient for the patient. This is the final diet framed according to the given specifications.
3.7 To recapitulate, the four steps, which follow in a logical sequence, are: first, find the patient,s current diet and personal likes and dislikes. Second, frame a provisional diet. Third, find how far the provisional diet meets the specifications. Finally, make a few adjustments to get exactly what you want.
3.8 Let us apply this knowledge to frame a 1200 Calorie diet. Before you go to the next slide, try to think for whom this diet might be required.
3.9 A 1200 Calorie diet might be required for a non-diabetic overweight adult. Or, it might be required for an overweight diabetic. A normal healthy 2-year-old child also needs a 1200 Calorie diet! Now you understand the importance of knowing your patient before framing the diet.
3.10 Let us assume that the patient in the present case is a nondiabetic overweight male.
3.11 The first step, as we have learnt, is to find the patient,s current diet, and his likes and dislikes.
This patient has at breakfast four buttered slices of bread, an omelette and a glass of milk. However, he does not mind skipping the butter, and likes a boiled egg equally well.
3.12 His lunch consists of 4 buttered chapaties, and a katori each of dal, vegetable and curd. He does not mind having fewer chapaties, but prefers to have them buttered.
3.13 In the evening, the patient takes three bananas and a cup of tea with two teaspoons of sugar. He loves bananas.
3.14 At dinner he takes a large helping of rice, two chapaties, and a katori each of dal and vegetable. Sometimes he also takes a sweet. He likes having rice at least once a day. He does not take salad but does not mind a few items such as onions, tomatoes and cucumber.
3.15 Having learnt the patient's usual diet and his preferences, the next step is to frame a provisional diet.
With experience, or exchanges, it is easy to estimate that the patient's current diet has more than 2000 Calories. Hence, in the provisional diet, we would reduce the quantity of food in order to reduce its energy content. However, to make the diet reasonably filling, we can introduce some raw or boiled vegetables and fruits. This will have the additional merit of providing the recommended amount of fruits and vegetables.
3.15
3.16 Let us start with breakfast.
We can cut down the slices of bread to two, remove the butter, have a boiled egg instead of the omelette, and reduce the quantity of milk to 150 ml.
3.17 At lunch, we may cut down the chapaties to two. In order to keep the diet still sufficiently filling, let us introduce some salad.
3.18 In the evening, we may reduce the bananas to just one.
3.19 At dinner, let us reduce the size of the helping of rice. Again, to keep the diet still sufficiently filling, let us introduce some salad.
3.20 Let us break the items of the provisional diet into ingredients. A slice of bread has about 15 g of wheat. Let us assume, for the present purposes, that a small egg weighs 30 grams, a serving of dal has 50 g dry dal and 2 g of the cooking medium, and a serving of vegetable has 100 g of a green vegetable and 2 g of the cooking medium.
The information is continued on the next side.
3.21 A reasonable serving of curd weighs 200 g, and a moderate sized banana weighs 100 g. We can suggest to the patient to add only 20 ml milk and one teaspoonful of sugar to his tea, and to restrict his helping of rice to 50 g of rice cooked in 3 g of oil.
3.22 Using largely the information you already have from previous exercises, you can calculate the nutrient composition and energy content of the provisional diet. Although the exact dal or vegetable consumed, and the items used for salad will vary from day to day, for the purposes of calculation, you may consider the dal to be black gram at lunch and green gram at dinner, the vegetable to be mustard at lunch and boiled potatoes at dinner, and salad to have 20 g onions and 50 g tomatoes at lunch, and 50 g radish and 100 g carrots at dinner. Changing the dal or vegetable from day to day will not make too much of a difference to the calculations. For 50information which is not available with you from the previous exercises, you may consult our bible, Nutritive Value of Indian Foods.
3.23 On doing the calculations, you would have found that the diet has 61 g protein, 35 g fat, and 242 g carbohydrate, and would provide 1529 Calories.
3.24 The next step is to make a few adjustments in the provisional diet to bring its energy content down to the desired level of 1200 Calories.
3.25 At breakfast, let us prescribe tea instead of milk. That would reduce the energy content by 67 Calories. At lunch, let us reduce the helping of dal by half. That takes away 95 Calories. If we cut down the helping of curd also to half, the diet loses another 60 Calories. We can reduce the quantity of dal at dinner also in the same way to half, thereby reducing the caloric content by another 95. If we add it all up, we find that the altered diet would have 317 Calories less.
3.26 Since the provisional diet had 1529 Calories, the altered diet would provide 1212 Calories, which is as close to what we want as we can get.
3.27 Discuss the altered diet with the patient. If he feels he would be able to stick to it, give it to him as the final diet. On the other hand, if he has some desires which can be accommodated without making a major change in the energy content, modify the diet appropriately. The diet which meets the specifications as well as the patient's approval is the final diet.
3.28 Try and reflect over the principles which have been employed to achieve reduction in the energy content of the diet while still providing adequate protein, vitamins and minerals, and satiety value. Do that before you go to the next slide.
3.29. The principles are very simple. Reduce the quantity of almost every item of the diet, specially fat. This is understandable because fat is a concentrated source of energy. By reducing fat, you can reduce the energy content of the diet efficiently without making a very heavy cut in its weight or volume. Balance cereal protein with pulse protein, and include liberal quantities of green vegetables, salad and fruits. The cereal-pulse mixture ensures adequate protein of reasonably good quality, and vegetables and fruits provide vitamins, minerals, water soluble fibre and phytonutrients. Vegetables and fruits also have another specific function here. Because of their high water and fibre content, they do not provide much calories, but all the same add bulk to the diet, thereby making it quite filling. This is specially important while framing the diet of a person who is fond of eating and is accustomed to large meals.
3.30 There are some additional things which have been done deliberately in the example illustrated here, not because they are necessary to reduce the energy content of the diet, but simply to explode some common myths.
Its fat content is low, but butter and cooking oil have not been completely excluded. It is the total energy content of the diet which is important, not the total exclusion of fat. In fact, some fat keeps the diet palatable and acceptable, and imparts satiety value to the diet. Dietary fat also facilitates the intestinal absorption of fat soluble vitamins.
Banana, rice and potatoes have not been excluded, because these are not ‘fattening foods’. In fact, there is nothing like a ‘fattening’ or ‘slimming’ food. It is the energy intake in relation to energy expenditure which determines the body weight. If the intake exceeds expenditure, any diet, no matter what it includes or what it excludes, will lead to gain in weight. For example, cattle grow fat if fed too much grass, and grass certainly contains no fat.
3.31 Now you deserve a brake before going to the next slide.
3.32 Let us now frame a diet for a pregnant woman during the second half of pregnancy.
3.33 Before we frame the diet, let us see why the diet of a pregnant woman needs special attention. This is because a pregnant woman has to eat not only for herself but also for the tiny but rapidly growing foetus. Therefore a pregnant woman not only needs more food, she also needs relatively more of nutrients required for growth, i.e. proteins, vitamins and minerals. If the diet of a pregnant woman is poor, the outcome is bad both for her and the baby. She often develops anaemia, osteomalacia, and other forms of malnutrition. The baby may also be born premature, underweight, and with poor nutritional reserves.
3.34 If we consult the ICMR book on Recommended Dietary Allowances, we find that a woman needs 300 Calories more during the second and third trimesters than what she required before pregnancy.
3.35 Therefore, we first have to find how much energy this woman needed before pregnancy. For that, we have to know her body weight, which changes a lot during pregnancy, and her physical activity, which generally does not change much during pregnancy. Let us assume her weight before pregnancy was 55 kg, and her physical activity moderate. The recommended energy intake for a 50 kg woman doing moderate amount of work is 2225 Calories, which is almost 45 Calories per kg body weight. Therefore for a 55 kg moderately active woman, the recommended energy intake would be 2450 Calories. Since the requirement during the second half of pregnancy is 300 Calories more, her requirement comes to 2750 Calories.
3.36 The rest of the exercise is not very different from the way you would frame a 2750 Calorie balanced diet for any adult, except that we can be a little more generous with foods providing proteins, vitamins and minerals. Hence, our specifications in scientific terms are that we have to frame a 2750 Calorie diet for a woman going through the second half of her pregnancy.
3.37 We have already learnt how to frame a diet according to given specifications. First, we should know the usual dietary pattern and personal likes and dislikes of the patient. These are particularly important during pregnancy because the patient may be having frequent attacks of nausea and vomiting, may not be able to eat too much at a time because of a distended abdomen, may be constipated, and may have some peculiar cravings. Second, we should frame a provisional diet keeping in mind the scientific specifications and the patient's individual needs. Third, we should evaluate the provisional diet by calculating its nutrient composition and energy content. Finally, we should make some adjustments in the provisional diet to get exactly what we want.
3.38 Here is a sample diet which meets the scientific specifications.
The diet continues on the next few slides.
3.39 When you are through with it, go to the next slide.
3.40. Try to be critical while going through these slides so that you can arrive at some general conclusions, and you have a mental picture of which foods provide roughly how much energy. Some foods like cheese have a high energy density, while others like salad have a low energy density. You should aim at developing a feel for the energy density and content of foods something like the way you have a feel for the density of wood and mercury.
When you are through with it, go to the next slide.
3.41 Go to the next slide when you are through with it.
3.42 This is the last meal of the day. Before you go to the next slide, reflect over the diet, and extract any general principles you can about framing a high calorie diet. Contrast these with the principles you picked up while framing a low calorie diet.
3.43 This is a summary of some features of the diet given in the previous few slides. You may verify these and discover some more when you have the time and inclination.
3.44 Pregnancy is followed by lactation. A lactating woman also has to eat for two. Moreover, since the newborn baby is heavier than the foetus, a lactating woman's nutritional requirements are even greater than those of a pregnant woman. ICMR recommends that if lactation continues for one year, the mother should have 550 extra-calories per day for the first 6 months, and 400 for the next 6 months. For example, our 55 kg moderately active woman who ordinarily needs 2450 Calories should have 3000 Calories during the first six months of lactation. The diet for a lactating woman can be framed using the same principles as those employed for designing the pregnancy diet.
3.45 You may now take a break before going to the next part of the exercise.
3.46 Now we come to the next exercise: to frame a diet for a one-year old. A one-year-old weighs about 9 kg, and as per ICMR recommendations, should get 101 Calories per kg body weight, i.e. about 900 Calories.
3.47 Framing a 900 Calorie diet is not difficult. But it is difficult to design a 900 Calorie diet which a one-year-old will eat. There is no 900 Calorie diet which any one-year-old will eat consistently, predictably and regularly.
3.47
3.48 What can be done is that, keeping some broad principles in mind, the child may be offered a variety of foods through the day. If that is done, no healthy child will starve itself. It may eat less on some days, but will make up by overeating on some other days. Therefore, instead of designing any rigid diet, it is better to provide broad guidelines to the parents. If there is any reason to assume that the child's diet is inappropriate, e.g. if the child's growth is unsatisfactory, the actual intake can be evaluated in terms of its energy content and nutrient composition.
3.49 The broad principles which should guide the foods offered to an infant are based partly on the science of nutrition and partly on child psychology. However, a child psychologist once said that before he had children, he knew six theories about bringing up children, but after he had six children, he knew not even one. In practice, successful and satisfactory feeding of a child is essentially a matter of commonsense.
By the time an infant is a year old, breast feeding is generally stopped. But from a scientific point of view, breast feeding may be continued longer. However, breast milk alone is insufficient after the age of four months. In fact, for a one-year-old, any milk, by itself, is inadequate. Starting with semisolids at about six months, the child should graduate to a wide range of solids by the age of one year.
3.50 While recommending specific solids for an infant, it is useful to remember that neither the acceptability nor the nutritional value of a food are determined by its cost. Judiciously selected ordinary, inexpensive, easily available foods are highly nutritious, and would be well-received by the child if served with love and some tact.
3.51 At this point, you might ask that it may not be necessary to recommend expensive foods, but at least one should recommend high protein foods because growing children need more protein than adults. Let us examine this common concept critically. An adult male weighing 60 kg and engaged in moderately heavy work needs 2875 Calories, of which at least 240 Calories, or about 8% should come from proteins. On the other hand, a child of one weighing 9 kilos needs about 900 Calories, of which at least 54 Calories, or about 6% should come from protein. Thus a one-year old child needs only 6% of his energy intake from protein while an adult needs 8%. Thus a child needs less protein! With figures, one can prove anything, you might sneer. But let us see in the next slide why this way of looking at facts is more logical while selecting foods.
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3.52. Our staple foods provide both energy and protein. If the percentage of protein calories in some foods matches the percentage of protein calories required by a person, these foods should be satisfactory. Fortunately this is true of cereals, and pulses provide a still higher percentage of protein calories. Therefore a cereal-pulse mixture has a higher percentage of protein calories than is absolutely necessary for any age group. Hence, even after dilution by foods such as sugar or oil, a diet based on a cereal-pulse mixture has sufficient protein. Further, a mixture of cereal and pulse protein is a good quality protein. Therefore, a diet providing most of the energy in the form of a cereal-pulse mixture also provides adequate protein of satisfactory quality for both children and adults.
3.53 We have derived a principle of nutrition which is so important that it is worth stating like a law: “If the quantity of food is enough, quality takes care of itself.” By quantity, here we mean energy content, and by quality, protein content.
3.54 Now let us enumerate a few concrete examples of solids that may be recommended for a one-year-old.
Khichri, Chapati and dal and Chapati made from a mixture of a cereal and a legume are examples of cereal-pulse supplements. Some other suitable supplements are: banana, mashed boiled potato and curd, toast, biscuits, boiled vegetables, and fruits.
3.55 There are some additional tips which are useful for feeding very young children. Introduce only one new food at a time. This gives the child time to get used to the food, and also facilitates identification of any food to which the childmay be allergic.
The menu should vary somewhat from day to day, A monotonous menu gets boring, and the child may start rejecting it. There is no contradiction between variety and the previous suggestion that only one new food should be introduced at a time. The one new food may be given constantly for about a week till the child gets used to it, but 69variations from day to day can be introduced in the other foods to which the child is already accustomed.
The helpings served to the child should be small. If the child is able to finish a helping, it gives him a sense oi achievement. Asking for a second helping gives him additional pleasure, which need not be denied.
There is a popular misconception that children mostly like sweet foods only. Like adults, children also prefer a mixture of sweet and salty foods.
If a child does not like a particular food, one need not insist on it. There is no single food without which the child cannot be fed satisfactorily. But a rejected food may be tried once again after a few months. After a gap, the rejected food may not only be accepted, but even relished. Conversely, do not be surprised if suddenly one day the child refuses to eat what was once his favourite food. The aversion is likely to be temporary, and it is best not to insist too much.
Children often love candy and other similar ‘junk’ food. In order to reduce the consumption of ‘junk’ food, its availability to children should be minimised. Too much of these foods may crowd out the appetite so that the child cannot have better foods. The disadvantage of junk food is that it may provide energy but not the proteins, vitamins and minerals which are coupled with calories in better foods. Thus like all rules, the rule that quantity looks after food quality has limitations and exceptions. The other situation where quantity may not take care of quality is when starchy roots and tubers like cassava are the staple food. These are so poor in protein content that enough energy from them does not guarantee enough protein.
3.56 In this exercise you have practised framing a reducing diet, a pregnancy diet, and a child's diet. These three examples cover a large and vital segment of your requirements. In addition, you have also seen how, through a combination of knowledge and common sense, you can frame a diet with given specifications.
4.1 In this exercise we shall learn how to improve a poor diet with minimum alteration and minimum additional expense.
4.2 A qualitative defect in the diet such as lack of fibre, or too much of cholesterol, may be apparent from a quick look at its constituents. Such a defect may be confirmed by calculation of the composition. But detecting a quantitative defect, that is, too little or too much energy content, may need actual calculation. Further, the appropriateness, or otherwise, of the energy content of the diet also needs 72knowledge of who is consuming it, or for whom it has been framed. This is necessary because the same energy content may be low, appropriate or excessive for different individuals. For example, an energy intake of 2200 Calories may be quite all right for a 50 kg non-pregnant woman doing moderate amount of work, too low for a 60 kg man doing heavy physical work, and too high for a 45 kg sedentary woman. Once we know all the quantitative and qualitative drawbacks of a diet in relation to the person consuming it, remedial alterations can be made to make the diet satisfactory. The alterations should be minimum and sould involve minimum additional expense so that the diet is still acceptable. If the changes that you suggest are not accepted, the whole exercise will be a waste of time.
4.3 Hence, improving a poor diet involves four basic steps. First, find the age, sex, physical activity and any other relevant characteristics of the person consuming the diet. Second, find the composition and energy content of the diet presently being consumed. Both these steps, coupled with knowledge ofthe recommended dietary intakes will tell us whether the diet is really poor, and if so, in what respect. Finally, remedy the defects of the diet by deleting, adding or substituting appropriate foods. The alterations should involve minimum change, and minimum additional expense, so that they are acceptable to the person concerned.73
4.4 As an example, let us evaluate the diet being eaten by a 2-year-old girl who has been brought to us in summer months due to repeated attacks of diarrhoea. She was weaned from breast milk about a year ago when her mother gave birth to another child. On examination, she has some signs of protein energy malnutrition.
4.5 Her present diet consists of three glasses of milk which are diluted to make four glasses, about two chapaties split into two or three sittings, half a katori of the watery supernatant of dal, about 6 biscuits, and occasionally some vegetable, if she likes it.
4.6 You now know how to calculate the detailed composition and energy content of this diet, but for practical purposes it is enough to know the energy content. As you have learnt already, if the diet is satisfactory in quantity, quality generally takes care of itself. The calculated energy content is 871 Calories. The recommended energy intake for a 2–year child is about 1200 Calories. The child clearly needs to eat more.75
4.7 Before we enumerate the steps which might improve this child,s diet, you should try to put down on paper the solutions that come to your mind.
Verify your thoughts with the help of the next slide.
4.8 Some measures involving minimum alteration in the child's current diet can be readily suggested to the mother. First, she should not dilute the milk. It is a popular misconception that children cannot digest undiluted milk. Healthy children can digest undiluted milk. Dilution may, however, help during diarrhoea because transient lactose intolerance is quite common in diarrhoea. Second, some butter or oil may be applied to the chapaties to increase their caloric content. Third, the child should receive proper dal instead of only the watery supernatant. There is a popular misconception that the watery part of dal and vegetables is highly nutritious. Since water gives no energy, these portions actually have a very low energy density. Fourth, some butter or oil may be added to the dal to increase its energy density further. Fifth, the mother may be told to avoid making spicy vegetables which children generally dislike. Finally, some convenient recipes may be suggested to add variety to the child's diet.
4.9 Let us now see how close the altered diet comes to the child's requirements. By making very few changes, we have been able to increase the energy content of the diet by 33 percent, and bring it to the desired level. Even the child 77would hardly feel that she is being forced to eat more; if anything, she may find that the food has suddenly become more palatable.
4.10 You might have observed that we have made the child's unsatisfactory diet satisfactory basically by increasing the caloric density through adding fat and by serving dal as such. The concept of caloric density is very important in child nutrition. As a child's stomach is small, his capacity to eat is limited. On the other hand, due to the requirements of growth and physical activity, a child's nutritional needs are heavy in relation to its body weight. Therefore in order to feed a child satisfactorily, we should try to pack more calories in a smaller volume and also provide the child a larger number of meals per day.78
4.11 Child nutrition is not difficult in itself. But under– privileged sections of the society, to whom childhood undernutrition is largely confined, have some difficulties. One should understand these difficulties in order to offer meaningful advice. Their resources are limited; hence, expenditure on food is an important consideration. Not only expenditure on food, even expenditure on fuel gets a thought; hence, the amount and frequency of cooking is minimised, and repeated boiling of milk is avoided. They cannot afford to cook separately for children and adults. Further, the women who may work during the day in fields or at construction sites have limited time to devote to their young children. And, of course, refrigerators for storage of food are out of the question. Therefore one should suggest to them foods which do not spoil fast, are not very expensive, and are equally suitable for children and adults. Some such foods are khichri, upma and dalia (porridge). Vegetables and dal may be cooked without chillies to start with. Chillies may be added after taking out a small quantity for children. Items which do not need cooking, such as biscuits, bread or banana come in handy.79
4.12 As another example, let us examine the diet of a 70 kg sedentary man, 55 years of age. He is a business executive who has come to us because he has lately been putting on too much weight. His breakfast consists of two paronthas, an omelette and a glass of milk. He often misses lunch but in the process of giving company to his visitors, he usually ends up having about 10 cups of tea, three cold drinks, two sandwiches, six biscuits and two samosas during the course of the day. In the evening, he is generally entertaining or getting entertained. Since he has missed lunch, he does not mind eating well at dinner. After relaxing over a couple of drinks, with which he takes some fried stuff, he takes a small helping of rice, two chapaties, a helping of meat or chicken, two or three vegetables, some dal and a sweet dish.
4.13 This type of intake, which is rather flexible, varies considerably from day to day. But the general trends are quite apparent, and for purposes of calculation, we can consider specific foods and quantities.
The information is continued on the next few slides.
4.14 When you are through with it, go to the next slide.
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4.15 When you are through with it, go to the next slide
4.16 When you are through with it, go to the next slide.
4.17 Use the facts in this slide and the previous few slides to calculate the composition and energy content of the diet.
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4.18 The calculations confirm that in spite of skipping his lunch, the patient is consuming an enormous diet providing more than 4000 Calories. In contrast, the ICMR recommendation for a 70 kg sedentary man of 55 years is 2552 Calories. If you have any other comments, write them down before going to the next slide.
4.19 Not only is the diet very high in its energy content, its protein and fat contents are also very high. The recommended protein intake for a 70 kg man is 70 g per day, while this diet has about double that quantity. Whether such high intakes are entirely safe in the long run is not well established. Further, the fat intake of our patient is nearly 200 g per day. Depending upon the cooking medium used, a large fraction of it could be saturated fat, which is likely to lead to hypercholesterolaemia and atherosclerosis. Moreover, too much of any fat, as well as obesity, lead to hypercholesterolaemia. Although there is no rigid recommendation for fat intake, ICMR suggests only 20 g/day of visible fat for adult males and nonpregnant females.
Before going to the next slide, write down what suggestions you would give to the patient to make his diet satisfactory.
4.20 It would be foolhardy to suggest to this patient a simple breakfast, lunch and dinner pattern based on cereals, pulses and green vegetables as neither his profession will permit it, nor his taste will tolerate it. However, the case is not beyond cure; we can still make several useful and feasible suggestions. First, the breakfast can be made lighter by taking away one parontha. Second, the patient has to be made aware that skipping lunch does not justify repeated sessions of tea and snacks. He can be a little more discrete in giving company to his visitors. In some cases, he can politely wriggle out completely; in others, he can have only a little bit just to 84fulfill the formality of giving company. Finally, he should resist the temptation for a heavy dinner, no matter how palatable the food. A few sensible rules of the thumb to follow at dinner would be to have rice or chapaties, not both; to have only one meat preparation, one vegetable and one dal; and to have plenty of salads to make up for the reduction in the quantity of other items.
4.21 Here is a sample diet based on the above suggestions.
The diet is continued on the next slide.
4.22 When you are through with it, calculate the composition and energy content of the revised diet.
Verify your calculations with the help of the next slide.
4.23 Here are the calculations for the revised diet as suggested in the previous few slides. Salads have been excluded from the calculations but, if included, would possibly raise the energy intake to exactly the recommended level.
You might have realised that when we tinker with diets to bring them in line with the desired specifications, the foods are axed or added somewhat arbitrarily although we do keep in mind some nutritional principles and the patient's preferences. In fact there are no clearcut wrong or right answers to how a given diet may be modified to achieve the desired result. The primary objective is to reach a scientifically satisfactory diet which is also acceptable to the patient.86
4.24 Since our patient has been on an excessive energy intake for a long time and has gained weight, there are two more things he should be advised to do. First, he should reduce the energy content of the diet to a level of 1200–1500 Calories for a few months till he has achieved a ‘normal’ weight. After that he can go to his normal requirements of about 2500 Calories. Second, he should introduce some physical exercise in his daily routine. That would not only keep him fit and normal in body weight, but also allow him some scope for a little dietary indulgence which is such an inseparable part of his lifestyle.
4.25 In this exercise, you have seen two types of malnutrition—undernutrition and overnutrition. Undernutrition in our 2–year old girl was due to a combination of poverty and ignorance, and we have seen how it can be corrected within the constraints of the resources. Overnutrition in our business executive was due to affluence, and possibly also ignorance of how much contribution snacks and tea can make if taken repeatedly throughout the day. The result was that the executive was malnourished in spite of consuming an expensive diet. Thus an expensive diet is not always good. Conversely, improving a diet does not necessarily involve additional expense; in fact, it might save money. Thus malnutrition has many facets, and so does its treatment.
5.1 Diet in disease is a fascinating subject because it is a mixture of facts and fancy, in fact, more fancy than facts. Some restriction or modification of diet is prescribed in almost every disease, often because the patient expects it. There are actually very few diseases where drastic modification of diet has a known scientific basis and proven value. In this exercise we shall examine the principles governing dietary advice in a few common diseases.
5.2 Let us start with diarrhoea. During the first five years of life, a child has diarrhoea 10–15 times on an average. Diarrhoea is responsible for about 25% of all the deaths in the under–5 year age group in India. The sad part is that most of these deaths could have been prevented with very simple measures.89
5.3 Diarrhoea affects adults also but it is more common and serious in children. It is more serious in children because its consequences are more deleterious in them. The main pathophysiological derangement in diarrhoea is fluid loss. The amount of fluid lost in an episode of diarrhoea is quite significant even in an infant because the surface area of the intestinal mucosa is relatively larger in an infant than in an adult. But the fluid lost forms a much larger fraction of the total extracellular fluid in an infant. For example, loss of one litre of fluid in an adult forms only 7% of the extracellular fluid, but in an infant weighing 5 kg, loss of half a litre of fluid takes away half its extracellular fluid. Therefore diarrhoea needs urgent and vigorous treatment in children. However, the principles of treatment are the same in both children and adults.
5.4 Now that we know why diarrhoea is important, let us see why diet is important in diarrhoea.
First, misconceptions about diet in diarrhoea are very widespread. People often starve in diarrhoea, which is quite unnecessary. Although nutrient absorption is reduced during diarrhoea, it still remains considerable. During health, we absorb about 90% of what we eat. During diarrhoea, we may absorb, say, 70% of what we eat. Therefore the body will still get quite a bit of nourishment from what we eat. Thus, starvation is not really warranted. Starvation only adds the problem of malnutrition to the other problems associated with diarrhoea.
Second, diarrhoea is associated with an abnormally high fluid and electrolyte loss. The loss needs to be replaced, and can be ordinarily replaced orally. Anything consumed orally is, in a way, part of the diet. Therefore, dietary treatment of diarrhoea includes replacement of fluids and electrolytes.
Third, intestinal damage in diarrhoea might result in a temporary deficiency of some brush border enzymes, notably disaccharidases, especially lactase. This might necessitate a temporary avoidance of certain foods.
Finally, diarrhoea may be a manifestation of the underlying undernutrition. Undernutrition impairs the capacity of the body to fight infections, including diarrhoeal infections. Therefore an undernourished child gets more episodes of diarrhoea. Due to excessive faecal nutrient losses during diarrhoea, the malnutrition gets worse. Thus a vicious cycle of malnutrition and diarrhoea is established, which can be broken only if the underlying malnutrition is also treated in addition to the acute episode of diarrhoea.
5.5 Now we will discuss the broad principles guiding the treatment of diarrhoea, the first and foremost of which is to replace water and electrolyte loss. The major electrolytes generally lost are sodium and chloride ions. Second, nutrients also have to be provided in diarrhoea, both to meet the everyday requirements and to cover the additional losses during diarrhoea. Further, combining electrolytes and nutrients in the same solution is not only convenient but also more effective because the intestinal absorption of glucose and some amino acids is coupled to that of sodium. The discovery of coupled transport in the intestine has influenced the treatment of diarrhoea so profoundly that it has been hailed as the most important medical advance of the century.
It is, of course, understandable that foods not well tolerated during diarrhoea, such as milk and fats, should be avoided. And, even after the diarrhoea stops, background malnutrition, if any, should be treated.
Finally, although drug treatment is outside the realm of the present exercise, for sake of completeness it may be mentioned that drugs have very little role in the treatment of diarrhoea. About 40% of diarrhoeal episodes are caused by viruses, for which we have no specific antiviral drugs. Therefore, cure depends on the fact that these diarrhoeas 92are self-limiting. For the other varieties of diarrhoeas also, drugs are generally not necessary. Nonspecific drugs such as binding agents, antimotility agents, and antisecretory agents may provide some symptomatic relief but, on the whole, they might do more harm than good. In short, the major part of the treatment required in diarrhoea is, most commonly, just fluids and foods. These aspects of treatment have been dealt with in some detail in the next few slides.
5.6 Replacement of fluids and electrolytes should be started without any delay. The quantity of fluids given should be just sufficient, neither too much nor too little. The composition of fluids given should also be appropriate.
5.7 Replacement of fluids and electrolytes should be done orally except in severely dehydrated patients. There are several reasons why oral rehydration is better than intravenous infusion. There is little risk of overhydration because fluid administered orally enters the bloodstream slowly enough for the kidneys to adjust the rate of urine formation according to the state of hydration. Renal compensation also reduces the risk of electrolyte imbalance resulting from a mismatch between the electrolytes administered and those lost. Oral rehydration carries little risk of infection because the gastrointestinal mucosa acts as a barrier to the entry of pathogenic organisms. On the other hand, with intravenous fluids, there is a real risk of infection, which may lead to thrombophlebitis, or even a systemic infection. Oral rehydration is so simple that it may be done at home, and naturally does not cost much.
5.8 Oral fluids should be given in small sips with a spoon in case of very small children. Older children and adults may be given the solution in a cup or glass, but even they should 94have only small quantities at a time, taking a few sips every 5 to 10 minutes. Large quantities at a time may induce vomiting, or may stimulate the gastrocolic reflex. Hence, small amounts of fluid at a time improve the chances of retention and reduce the chances of further losses.
5.9 The type of solution used for oral rehydration depends on the degree of dehydration. If the treatment is started at such an early stage that no significant dehydration has set in, the aim of treatment is simply to prevent dehydration. For this purpose, a large number of fluids are suitable, for example, nimbupani with salt and sugar, coconut water, buttermilk (lassi), rice kanji with salt, or weak tea. Any of these which is readily available, and liked by the patient, may be given in small quantities at a time repeatedly.
5.10 If mild dehydration is already present, a specially made solution, often called an oral rehydration solution (ORS) should be given. One such solution is prepared by dissolving in one litre of clean, preferably boiled, water, 8 teaspoonfuls or 40 g of sugar, one teaspoonful or 5 g of salt, and the juice from one lime, if available. In some field situations, where accurate measurement by counting spoons may not be dependable, it is has been found useful to give the instructions like this: Boil two glasses of water. Cool the water. Add to it a pinchful of salt, using the thumb, index and middle fingers, taking the salt only up to the first crease. Stir the solution well. To make sure that the solution is right, taste it before giving it to the patient—it should taste just as salty as the tears. Then add one fistful of sugar and dissolve it by stirring.
It has been found that if 50 g of puffed rice powder is dissolved along with 5 g of salt in one litre of water, we get a solution just as satisfactory as the salt and sugar solution. Part of rice powder may even be replaced by thin watery khichri. It is quite possible that a large number of commonly available foods can give satisfactory oral rehydration solutions. Much research is currently going on in many parts of the world, including India, to test a variety of oral rehydration solutions so that treatment of diarrhoea can be achieved through locally available, culturally acceptable foods. Popularising such options would go a long way in preventing diarrhoeal deaths.96
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5.11 If the dehydration is moderate, it is generally recommended that it is preferable to give the standard WHO oral rehydration solution. WHO ORS is available pre-packed in a dry form to be reconstituted by dissolving in clean drinking water. As a broad guideline, a one year old infant may be given one litre of ORS in one day to correct moderate dehydration. In addition, half a glass, or 100 ml of ORS may be given for each loose stool.
In order to prevent contamination, it is better to reconstitute only small quantities of the ORS at a time; in any case, we should not keep the reconstituted solution for more than 12 hours. As a general rule, we should be specially careful about the hygiene of any food or drink given to a patient with diarrhoea.97
5.12 Besides oral rehydration, the patient also needs some food. The nature of food depends on the age of the patient. If the patient is a breast-fed infant, breast feeding should be continued. Breast milk is sterile and easily digested. Any change in the diet of a breast-fed infant can only be for the worse. However, diarrhoea in breast-fed infants is rare.
More commonly, the patient is an infant who has been weaned, and is on some other milk. In such cases the milk to which the baby is accustomed should be continued, but after dilution with equal volume of water. Dilute milk is well tolerated even if there is a transient digestive enzyme deficiency, which is quite common in diarrhoea, and lasts from 3 days to 2 weeks. When diarrhoea stops, feeding with the undiluted milk should be resumed.98
5.13 If the child is older and takes semisolid or solid supplements in addition to milk, he may be given khichri or some other cereal preparation, preferably made from milled, not whole, grains because the additional fibre in whole grains makes the stool softer and bulkier. Other suitable foods include mashed potatoes with curd, mashed banana and egg. However, excessive sugar intake should be avoided because it may increase the osmotic pressure of intestinal contents, and make the stool more liquid. Other foods to avoid are soft drinks, and fruit juices, again because of their high sugar content.
5.14 Having talked about diarrhoea, now let us turn to the other extreme, that is, constipation. Constipation is neither an acute problem nor can it create an emergency 99like diarrhoea, but it still is an annoying and potentially serious condition. Diet does not provide the full answer to constipation, and sometimes may not help at all. But all the same dietary changes are a rational part of the treatment, and are frequently successful.
5.15 The basic principle underlying the treatment of constipation is to provide a high fibre diet. Dietary fibre is not digested by the endogenous gastrointestinal enzymes, and therefore reaches the colon intact.
5.16 In the colon, a part of the dietary fibre undergoes fermentation by the colonic bacteria. However, the part which is fermented, and the part which does not get fermented, both contribute to faecal bulking. The part which is fermented encourages bacterial growth, and thereby increases the bacterial mass in the faeces, and consequently the faecal mass. Further, the short chain fatty acids and other products of fermentation help raise the osmotic pressure of the intestinal 100contents, and thereby increase the volume of the colonic contents. The part of fibre which is not fermented holds water, swells up, and increases the volume of the colonic contents. Increase in the volume of the colonic contents stimulates colonic motility, which reduces the time available for absorption of water in the colon. Increase in the amount of water left behind in the colon itself makes a contribution to the faecal bulk as well as softens the faecal consistency. Thus there are multiple mechanisms by which fibre may relieve constipation.
5.17 Dietary fibre is present only in foods of plant origin, and is more abundant in the husk. Accordingly, a high fibre diet should have more of plant foods in which the husk is intact. In other words, a high fibre diet should have chapaties made from whole wheat flour, brown bread, brown rice, and whole pulses. Chapaties should be made without passing the atta through a sieve. The dehusked forms of grains should, naturally, be avoided. Fruits and vegetables also have fibre, but not as much as whole cereals and pulses. These should be consumed with the skin and seeds wherever possible.101
5.18 If constipation is not relieved by a normal high fibre diet, or if the patient‘s life style makes a high fibre diet inconvenient, a high fibre supplement may be consumed. Commonly used concentrated forms of fibre are ispaghula husk or Isabgol, and wheat bran. Two teaspoonfuls of Isabgol, consumed with milk, curd or water, are very effective as faecal bulking agents. Since isabgol needs water to swell up, it is advisable to down the isabgol with two glasses of water. Laxatives have no role in the routine treatment of chronic constipation. In fact, laxatives may perpetuate constipation, and are, therefore, best avoided.
5.19 Peptic ulcer is another common disease of the gastrointestinal tract in which modification of diet might be helpful. There has recently been much rethinking on the subject. The traditional teaching was that patients with peptic ulcer should take a low fibre diet. But when Denis Burkitt and Hugh Trowell hypothesised in the seventies that a low fibre diet might increase the risk of getting a peptic ulcer, the traditional peptic ulcer diet was seriouly questioned. Now we have studies by Andreas Rydning suggesting that, in fact, a high fibre diet might reduce recurrences and prolong remissions in peptic ulcer. A recent review by Ryan-Harshman has confirmed that a high fibre diet, particularly if the fibre comes from fruits and vegetables, is good for peptic ulcer.
5.20 Second, the traditional peptic ulcer diet has been devoid of spices, specially chillies. The advice has been based on commonsense rather than hard evidence. A 1956 study by Richard Doll, a father figure in epidemiological studies, found that a bland diet was not better than a normal diet for peptic ulcer. A recent Indian study found that oral intake of 3 g chilli powder everyday had no deleterious effect on healing of duodenal ulcers. Thus, the entire concept of dietary treatment of peptic ulcer is currently in a state of flux. Mercifully, our dependence on dietary treatment is also much less now because very efficient and specific inhibitors of gastric acid secretion are available.
5.21 In the current state of flux, probably the advice to a patient with peptic ulcer should be very simple. First, the patient should take small frequent meals. This ensures nearly constant availability of food in the stomach for the acid to act on. Secondly, the patient should take a normal diet, avoiding just those specific items that are known to generally cause epigastric discomfort in such patients. To some extent the items to be avoided can be individualised on the basis of 104subjective experience. Only those items may be avoided which the patient‘s own experience has shown to induce discomfort. Finally, knowing the effect of the mental state on gastric secretion, the patient should not worry too much about anything, including food. He should not feel unduly deprived due to avoidance of some foods. For example, if avoiding alcohol is more stressful than alcohol itself, let the patient enjoy his drink. Similarly, anxiety about irregularity in meal timings may be more harmful than the irregularity itself. All this advice has been beautifully summed up in the dictum that a patient with peptic ulcer should avoid “hurry, worry and curry”.
5.22 A common gastrointestinal complaint which might benefit from dietary changes is gas. Troublesome expulsion of gas may occur at either end—it may be belched up through the mouth, or it may be passed as flatus through the anus. Though both the complaints may be described by the patient as ‘gas‘, their mechanisms and treatment are entirely different.105
5.23 Let us first start with belching. It could be the result of swallowing too much air while eating, or inappropriate relaxation of the lower esophageal sphincter, resulting in gastroesophageal reflux, or a combination of both.
5.24 Swallowing too much air is generally due to anxiety or nervousness. The patient should relax, and eat slowly. Gastroesophageal reflux might benefit from a reduction of fats, tea, coffee, chocolate, citrus fruit juices, peppermint and alcohol in the diet because all these are known to relax the lower esophageal sphincter. A high protein diet might help because proteins in the meal increase the lower esophageal sphincteric pressure. In addition, smoking should be avoided because that relaxes the lower esophageal sphincter.106
5.25 Flatulence, on the other hand, is due to gases produced by bacterial metabolism, mostly in the large intestine. Bacteria ferment the undigested carbohydrates and proteins that reach the large intestine, and also many components of dietary fibre which cannot be digested by our endogenous gastrointestinal enzymes. The products of fermentation include gases such as carbon dioxide, hydrogen, methane and ammonia: a rather foul smelling and explosive mixture. However, it is clear from the mechanism of flatulence that it is impossible to stop the production of gases in the large intestine completely.
5.26 Flatulence can, however, be reduced through two types of measures. First, the amount of fermentable material reaching the large intestine should be reduced. Second, an effort should be made to alter the bacterial population of the large intestine in such a way as to reduce the type of bacteria which make gaseous products, and increase those which do not.
5.27 There are very few dietary sources of fermentable material which can be conveniently reduced without compromising the overall quality of the diet. Dietary fibre is an essential constituent of diet, and it would be foolhardy to switch over to refined cereals and dehusked dals just to reduce flatulence. What can be done is to reduce or avoid completely a few dals known to contain large amounts of indigestible oligosaccharides which are readily fermented by bacteria. These oligosaccharides, of the raffinose group, do not have the desirable qualities of dietary fibre, and therefore can be eliminated from the diet without doing any harm. Various types of beans contain large amounts of these oligosaccharides. In contrast, legumes such as green gram do not have these oligosaccharides and are therefore less flatulent.
Some adults are intolerant to lactose due to lactase deficiency. In these individuals, undigested lactose reaches the large intestine, where it is fermented resulting in production of gases. Such individuals should reduce the 108amount of lactose in the diet by taking tea instead of milk. They can also take curd because curd has less lactose than milk.
Unripe bananas have some starch, known as resistant starch, which is not digested by amylase. This starch reaches the large intestine undigested and contributes to flatulence. Hence unripe bananas should also be avoided.
In general, any food which the patient finds, through personal experience, to increase flatulence, should be avoided. Flatulence is a problem which varies considerably from individual to individual due to factors which, to cover our ignorance, we call constitutional factors.
5.28 Manipulating bacterial flora of the gut by dietary means is a controversial and uncertain proposition, but there is no harm in trying. What might possibly help is reducing fat and protein, specially animal protein, in the diet, and increasing the quantity of curd in the diet. Curd is itself a bacterial culture, and might help by inducing a competition between its lactobacilli and the pre-existing flora, such as the coliforms.109
5.29 It is, however, good to remember that production of gases in the large intestine is a physiological phenomenon. All of us produce flatus; it is only the degree which varies. Flatus may be inconvenient but is not unhealthy. Making this fact widely known might make flatulence more acceptable in society.
5.30 One obvious case for predominantly dietary management is food allergy. The treatment essentially consists in eliminating the food to which the individual is allergic. One of the better known food allergies, which is partly responsible for many cases of malabsorption syndrome, is gluten sensitive enteropathy. Since gluten is the protein present in wheat, barley, buckwheat, oats and rye, the treatment is to eliminate these grains from the diet. This may appear very simple, but it is easy to forget that items such as cake, pastries, and noodles also have wheat. The list of permitted and prohibited foods is given in this slide and continued in the next one.110
5.31 The list continues on and on, as you see, even simple things like ice cream, Bournvita, instant coffee or beer may contain one of the gluten-containing grains.
Before we leave the gastrointestinal diseases, you may take a break, and discuss any questions that you might have.111
5.32 Now we move to another controversial area—diabetic diets. Himsworth, through simple but elegant studies, demonstrated quite clearly the beneficial effects of high carbohydrate diets in diabetics as early as the 1930s. But his studies were ignored and soon forgotten, and low carbohydrate diet became the norm for diabetics. Now we have travelled full circle, and rediscovered the favourable effects of high carbohydrate diets on glucose tolerance. Along with that, we have discovered many other new things also within the last two decades, which is rather a short time for clinical practice to undergo revolutionary changes. But the new findings have created a controversy, an atmosphere for 112rethinking, and some real change. What we will talk about here may be considered the golden mean, if any such thing is possible in a state of flux.
5.33 The aims of dietary management of diabetes are first, to assist good glycaemic control; and second, to reduce the risk of complications.
5.34 Let us see how diet can assist good glycaemic control. It can do so in two ways: first, by reducing postprandial glycaemia; and second, by improving glucose tolerance.
5.35 This slide shows how reduction in postprandial glycaemia can assist glycaemic control. Good glycaemic control, in the context of diabetes, means maintaining a relatively low overall blood sugar level. However, blood sugar level is never constant—it rises after every meal, and falls during the postabsorptive period. The overall blood glucose level may be considered to be the integrated average of blood sugar values over a period of, say, 24 hours. The integrated average would be affected by the degree of rise after every meal. If we can reduce the upward excursion in blood sugar level after every meal, we would achieve a lower average over the day. Thus reduction in postprandial glycaemia can improve glycaemic control.
5.36 Let us now examine how improvement in glucose tolerance can improve glycaemic control. Glucose tolerance is commonly measured in terms of the postprandial glycaemia following a standard oral carbohydrate load. Better the glucose tolerance, lower the postprandial glycaemia. In other words, the meal remaining the same, postprandial glycaemia is reduced when the glucose tolerance is better.
For example, if you look at the slide, in the upper graph are two plasma glucose curves, A and B, both in the same person after an identical meal, i.e. 75 g glucose. But these curves have been obtained on different days: curve A before, and curve B after improvement in glucose tolerance. In the lower graph also, there are two plasma glucose curves, A and B, both in the same person after an identical test meal but on different days. The effect of improvement in glucose tolerance is clearly visible, and is similar to that in case of the glucose meal.
In short, we have two ways of achieving the same end. We can select the type of foods which are associated with lower postprandial glycaemia.
Second, we can give foods, the long term effect of which is to improve glucose tolerance so that postprandial glycaemia following a given meal is lower.
5.37 The second aim of dietary management of diabetes is to reduce the risk of complications. Many of the complications are reduced by a good glycaemic control. Most of the others can be reduced if, in addition to a good glycaemic control, serum lipids are also favourable.
Favourable serum lipids essentially means low total cholesterol, low LDL cholesterol, high HDL cholesterol and low triglycerides. If one wishes to look at just one figure as an index of serum lipids, probably LDL cholesterol is the best indicator, the desirable levels being below 130 mg/dl.
5.38 We can, therefore, say that a rational diabetic diet should emphasise foods, the acute effect of which is a low postprandial glycaemia, and the long term effect of which is an improvement in glucose tolerance and better serum lipoprotein profile. Fortunately, the same foods possess all these qualities, and we shall see in the next few slides what those foods are.117
5.39 It was generally believed that simple carbohydrates like sugar would lead to a much higher postprandial glycaemia than complex carbohydrates like starch. Experimental studies have shown that this is true only if the meal consists solely of sugar, or solely of starch. But generally sugar is a part of a sweet or a drink like tea or coffee. If a simple carbohydrate is ingested in association with protein, fat, or a viscous form of dietary fibre, the postprandial glycaemia is considerably attenuated. On the other hand, all starchy foods are not alike with respect to postprandial glycaemia. For example, potato, polished rice or white bread give a higher glycaemic response than brown bread or brown rice. Further, crushed brown rice give a higher glycaemic response than whole brown rice, and amylopectin containing foods give a higher glycaemic response than corresponding foods containing starch in the form of amylose. Cooking, processing and storage also seem to affect the glycaemic response to a food.
In short, the response is determined by so many factors, some known and some quite certainly unknown, that there is no short cut to determining the glycaemic response to each food, and perhaps to each dish. This work, which is so essential for placing diabetic diets on a scientific footing, is still not complete. But it has reached a stage where glycaemic response is widely accepted as a rational basis for diabetic diets.118
5.40 Glycaemic response has been quantified in terms of the incremental area under the 3–hour glucose curve. Incremental here means the increase above the fasting level. The incremental area following ingestion of the test food is expressed as a percentage of the corresponding area following ingestion of a reference food. Of course, the amount of carbohydrate in the test food and reference food has to be equal, and is generally fixed at 50 g. The reference food commonly used these days is white bread. The figure arrived at in this fashion is called the glycaemic index.119
5.41 The glycaemic index of a few common foods is given in this slide. As you would notice, cereals, potato and banana have a higher glycaemic index than legumes. Therefore, besides complementing the protein quality of cereals, legumes also tend to lower the glycaemic index of meals. Also note that ice cream, which contains sugar, has a very low glycaemic response. Thus sugar is not taboo for a diabetic any more, provided it is incorporated in a food with a low glycaemic index. And, the glycaemic index of a sugar-containing food will be low if sugar gets the company of protein, fat or fibre, preferably at least two of these.
5.42 Foods which, over the long-term, improve glucose tolerance and lipid profile have a lot in common with foods which have a low glycaemic index. Let us first take glucose tolerance. Two characteristics of the diet which seem to improve glucose tolerance are high carbohydrate content, and 121high fibre content. Cereals and legumes are high carbohydrate foods, and if taken whole, contribute substantially to fibre intake. Thus a diet made up primarily of whole cereals and legumes is not only accompanied by low postprandial glycaemia, but also improves glucose tolerance in the long run.
5.43 Dietary factors which improve lipoprotein profile are somewhat controversial, but the current consensus is towards reduction in total fat, primarily at the expense of saturated fats. Polyunsaturated fats are encouraged, but even their level should be less than 10% of energy intake. Cholesterol, sodium and alcohol intake should also be restricted. Last but not least, a desirable body weight should be achieved and maintained, and for that, energy intake may be reduced and physical activity increased if necessary. These dietary goals are quite compatible with reduction in postprandial glycaemia and improvement in glucose tolerance. We shall talk in greater detail about these factors when we discuss the diet for prevention and treatment of atherosclerosis.122
5.44 Having examined the general principles, let us now see some practical considerations while prescribing diet for a diabetic. The first factor to be considered is the energy content of the diet. Besides other factors which we already know, in diabetes, body weight is a specially important consideration while prescribing the energy intake. If the patient is underweight, as often happens in young insulin-dependent diabetics, extra calories should be given. If the patient is overweight, as is frequently the case in non-insulin dependent diabetics, caloric intake should be reduced to facilitate normalisation of weight. Weight reduction has special significance in obese diabetics because simply reducing the weight generally improves glucose tolerance, and in mild cases, may be enough to cure the patient. A rule of the thumb to determine how much weight to aim at is to subtract 100 from the person's height in centimetres. For example, normal weight of a 160 cm adult is 60 kg. In case of diabetics, we should aim at a weight 10% below this normal weight. Thus in this example, we should aim at a body weight of 54 kg.123
5.45 An unending debate on diabetic diets has been going on regarding the optimum distribution of energy intake into carbohydrates, proteins and fats. We have already learnt that now we have travelled full circle, and high carbohydrate diets are considered acceptable and even desirable for diabetics. But in view of the fact that glycaemic response is not necessarily related to the percentage of carbohydrate in a meal, it is no more necessary to be rigid about the exact caloric distribution. As a broad guideline, a distribution of 60–70% carbohydrate, 15–25% fat and 15–20% protein is quite satisfactory. This distribution is quite compatible with a normal Indian diet.
5.46 The next point to be considered is the distribution of food into meals. Since a diabetic has a limited reserve of insulin, and in addition, may take a fixed amount of insulin or an oral hypoglycaemic agent at fixed timings some rigidity and regularity in terms of quantity and timings of meals is essential. If a heavy meal is taken when not much insulin is available, it may result in hyperglycaemia. On the other hand, if a meal is missed when insulin or the hypoglycaemic agent are at peak activity, the patient may get hypoglycaemia, which is even worse than hyperglycaemia. In order to avoid the necessity for excessive mobilisation of insulin which may be impossible for the patient, heavy meals should be avoided. Therefore, the pattern which suits the patient best is that of small frequent meals which are fairly constant in terms of amount as well as timings. A schedule suitable for our country consists of three main meals and two or three light meals.
5.47 For the patient, broad principles may not be enough, and he may need a chart. Having decided the energy content of the diet, there is no harm in giving a chart based on food exchanges. Of course, we should remember that all items in an exchange are not really exchangeable because their glycaemic responses may be quite different. Provided the factors governing glycaemic response are kept in mind while selecting items from exchanges, there is no harm in using the exchanges.
5.49 Let us examine the relative contribution of various nutrients to the caloric content of the 2200 calorie diet outlined in the previous two slides. As seen here, the distribution is quite consistent with the principles we have outlined.
5.50 The patient should also know that diet or drug treatment needs adjustment during any condition which influences substrate utilisation in the body, e.g. exercise or illness.
5.51 Besides diet, the other pillars of management of diabetes are exercise and insulin or oral hypoglycemic agents. Exercise helps in two ways. First, by facilitating weight control, it helps improve glucose tolerance. Second, by using up glucose, it improves glycaemic control. To these tranditional ‘pillars‘ of treatment, we may add stress management, which is important not only for the patient to feel better, but also to get better.
5.52 If the patient has any other disease besides diabetes e.g., heart, liver or kidney disease, the diet might require special attention to take adequate care of all the metabolic peculiarities of the patient.
5.53 Thus you would have observed that the diet of a diabetic is not really different from a good, balanced, prudent diet for any healthy individual, except for a little extra attention to fixed quantity and timings. Hence no special effort is required for meal preparation if there is a diabetic in the family. On the contrary, if all members of the family eat what the diabetic eats, it would be good for everyone.
5.54 Although hyperlipidaemia frequently accompanies diabetes, it may also occur independently of diabetes. Hypercholesterolaemia is a major risk factor for coronary artery disease. Now we know that LDL cholesterol is an even better indicator of the risk, and HDL cholesterol is an indicator of the protection available. In view of this, HDL/LDL ratio, or HDL/total cholesterol ratio, may be the most appropriate indicators of risk for coronary artery disease. Since lipoprotein profile is an objective, easily measurable variable, for all practical purposes, a diet suitable for coronary artery disease and other forms of atherosclerotic disease is one which improves the lipoprotein profile.
5.55 Among dietary factors which affect serum cholesterol levels, we can first consider cholesterol itself. It is good to remember that cholesterol is not a poison. It is a normal and essential constituent of the body. If we do not eat any cholesterol, the body manufactures it to meet our requirements. Further, the level of synthesis is finely regulated. If we take more cholesterol in the diet, less is synthesised in the body; if we take less cholesterol in the diet, more is synthesised in the body. But there are limits to this regulatory mechanism. If we take too much cholesterol in the diet, serum cholesterol level rises. Hence, limiting dietary cholesterol has some role in preventing hypercholesterolaemia. Further, the regulatory mechanism is not equally efficient in all. Some individuals, called hyperresponders, show a pronounced 130hypercholesterolaemic response to even moderate doses of dietary cholesterol. The only way to find whether one is a hyperresponder is to either try taking an egg everyday for two weeks; or if one is already taking eggs regularly, to stop eggs for two weeks. If either of these changes makes a difference to serum cholesterol levels which really matters, it is advisable to give up high cholesterol foods.
5.56 For reducing dietary cholesterol, we should know which are the high cholesterol foods. By avoiding these foods, we can reduce the amount of cholesterol in our diet. It may come as a relief to know that no plant food, including vegetable oils and dry fruit, has any cholesterol. Among animal foods also, milk and ordinary meat are not high cholesterol foods. Only glandular meats and brain have a high cholesterol content, but then, who eats brain curry every day. Fortunately egg is the only high cholesterol food in the usual Indian diet. Within the egg, the cholesterol is confined to the yellow part. Each egg has 250 mg of cholesterol. According to the American Heart Association and several other professional groups, up to 300 mg of cholesterol per day is permissible. Since the usual Indian diet has no other major source of cholesterol, one egg per day still leaves our dietary cholesterol intake within permissible limits. However, it is better for the hyperresponders to avoid yellow of the egg.131
5.57 Far more important than dietary cholesterol itself are dietary factors which raise serum cholesterol through alterations in lipid metabolism. The nutrient which has attracted the maximum attention in this respect is fat. In general, saturated fats (SFA) raise serum cholesterol while polyunsaturated fats (PUFA) lower it. There is also a third variety of fatty acids, the monounsaturated fatty acids (MUFA). MUFA are relatively neutral, but when they replace SFA, they have a cholesterol-lowering effect. However, every type of fat has its own importance, and all types of fatty acids should be taken in moderation. Moreover, the diet does not contain purified SFA, MUFA or PUFA, but edible fats and oils, which are a mixture of fatty acids. Animal fats such as butter and ghee are saturated, and so are coconut oil, palm 132oil and hydrogenated vegetable oils. A good source of MUFA is olive oil, but modest quantities of MUFA are also present in butter, ghee, palm oil and mustard oil, and in a variety of nuts such as almonds, walnuts and peanuts. Rich sources of PUFA are vegetable oils, specially corn oil, sesame oil, sunflower oil and fish oils. Considerable quantities of PUFA are also present in other vegetable oils, such as mustard oil, soyabean oil and groundnut oil, and in the various nuts.
5.58 Further, polyunsaturated fatty acids (PUFA) are also not a homogenous entity. They are broadly of two types, n-3 and n-6, depending upon the position of the first double bond, counting from the methyl end. The difference is physiologically 133relevant because PUFA are the precursors of thromboxanes and leucotrienes. The type of PUFA used for the synthesis of these compounds is somewhat flexible, and depends on what type of PUFA happens to be available in abundance. In general, the thromboxanes and leucotrienes synthesized from n-6 PUFA are more likely to produce platelet aggregation and are more inflammatory than those synthesized from n-3 PUFA. Now, it so happens that all the PUFA in most of the unsaturated fats is of the n-6 variety. In fact, the only edible oils of vegetable origin which have significant quantities of n-3 PUFA are mustard oil, canola oil and soyabean oil. Besides these, the other sources of n-3 PUFA are fish oils, and the invisible fat in beans and green leafy vegetables.
5.59 Current recommendations of the Indian Council of Medical Research regarding dietary fats are that the total fat intake should be restricted to less than 30% of the daily energy intake. Further, the fat intake should be roughly equally divided between saturated, monounsaturated and polyunsaturated fats, the PUFA/SFA ratio being 0.8 to 1. Finally, the n-6 to n-3 ratio should be between 5 and 10. In the Indian context, this generally means no reduction in the total fat intake, but it may need a shift of the cooking medium to either mustard oil or soyabean oil. It also means that, provided the total fat intake and energy intake do not exceed the appropriate limits, moderate quantities of saturated fats such as ghee are no longer taboo.
It has also been recommended that cholesterol intake should be restricted to 200 mg per day. One egg contains about 250 mg of cholesterol. If the diet does not have any other appreciable source of cholesterol, as is usually the case in Indian diets, consuming one egg per day still leaves the cholesterol intake within permissible limits. Salt intake should be restricted to 8 g/d, which may entail some hardship for quite a few Indians. Alcohol intake is not to be encouraged, but if taken, should be limited to 60 ml ethanol per day.
5.60 Coming to some finer points regarding fats, ghee is possibly better than butter because of higher content of an anti-atherogenic and anti-carcinogenic fatty acid, conjugated linolenic acid. Hydrogenated fats are better avoided altogether because of their high content of trans-fatty acids, which promote atherosclerosis. Nuts, being plant foods, contain no cholesterol, and their fats are unsaturated. But their high fat content means that their energy content has to be taken seriously. Just 20 g of nuts are the equivalent of one chapati, and this is important for those who want to lose weight, or do not want to put on weight. Among various nuts, the humble walnut has emerged a sort of winner because of its being just about the only nut with a significant n-3 PUFA content.
5.61 Several nutrients other than fats are also now thought to be relevant to prevention of heart disease. These include dietary fibre, folic acid, other B-vitamins, antioxidants and several other micronutrients, sometimes collectively called phytonutrients because most of the desirable ones seem to be concentrated in plants. In practice, all these nutrients can be obtained by taking whole grains, plenty of vegetables and fruits, and moderate amounts of spices.136
5.62 If heart disease—ischaemic, valvular or any other type—reaches a stage where the heart fails as a pump, the patient gets signs and symptoms of congestive cardiac failure. In this condition, salt and water retention is common, resulting in oedema.
5.63 Management of congestive heart failure requires drugs as well as close medical supervision. But we are concerned with only the dietary component of the treatment. The principles of dietary management are, first, to restrict salt and fluid intake in order to reduce oedema.
Secondly, light and easily digestible meals should be provided to reduce strain on the heart during digestion. Constipation should be avoided to avoid straining, which also imposes a load on the heart.
If the restrictions make it difficult for the patient to get enough energy, vitamins and minerals, suitable supplements may be added.
5.64 Salt restriction actually means sodium restriction. In acute stages of the disease, sodium should be restricted to 1 g per day. This can be accomplished by stopping all addition of common table salt, and by avoiding high salt foods such as pickles, chutneys, snacks, processed and preserved foods, and salted butter.
When the acute stage has passed, some salting of the food may be permitted, allowing only one level teaspoonful of salt per day.138
5.65 Severe fluid restriction is generally not necessary unless the kidneys are damaged. Excess fluid intake increases the work of the kidneys, which should be avoided. On the other hand, severe fluid restriction might make it difficult for the kidneys to excrete waste products. On the whole, it is better to maintain an intake-output chart, and see to it that the two are equal. If the patient is on diuretics, an intake-output chart would be essential.
5.66 We know that splanchnic blood flow increases after a meal. If the meal is large, and difficult to digest, the increase in blood flow is greater. Increase in blood flow through a large vascular bed like the splanchnic necessitates an increase in cardiac output, and hence imposes a volume overload on the heart. This overloading can be reduced if the meal is small and easy to digest. In order to meet the nutritional requirements, whenever the meals are small, they have to be more frequent.139
5.67 Straining at stool increases the abdominal and thoracic pressures. This also overloads the heart, and can be avoided by preventing constipation. This, we have already learnt, may be achieved by having adequate fibre, fluids, and physical exercise.
5.68 A patient with congestive heart failure may need several supplements.
Since the patient is on a sodium restricted diet, some potassium chloride may be used to make the food less unpalatable. In addition, extra-potassium may also be needed if the patient is on digitalis, or on a diuretic which produces potassium loss.
Dietary restrictions and loss of appetite may make it difficult to meet nutritional needs. Hence, high energy supplements, such as jams, jellies, malted chocolate preparations, etc. may be helpful. In addition, vitamins and mineral supplements may also be valuable.140
5.69 Two other organs of the body, the affliction of which may also give rise to oedema, are the liver and kidneys. Let us have a look at the dietary treatment in failure of these one by one.
5.70 Hepatitis, usually viral, is a common acute disease of the liver. Its most prominent symptom is jaundice. Attention to diet may be required to compensate for anorexia, nausea and vomiting associated with the disease, and sometimes to take care of disturbances in intermediary metabolism which may even manifest as encephalopathy.
5.71 In the acute stages, if vomiting is severe, intravenous fluids may be required to replace fluids and 141electrolytes and to provide nourishment. But often cautious oral feeding is adequate. A large breakfast is often useful because nausea is usually less in the morning.
5.72 The energy intake should be adequate. Carbohydrate content of the diet should be high in order to promote glycogen synthesis and to spare protein. But glucose or sugar cane juice have no proven hepatoprotective value, although these are traditionally forced on the patient in large amount. However, if the patient likes these sweet drinks, they are quite harmless, and may provide some precious, readily assimilable calories.
Protein should be adequate and good in quality so that most of it is used for synthetic purposes. Poor quality protein, which is burnt down to urea, makes the liver work for synthesising urea. Protein restriction is, however, required if the patient has encephalopathy.
Fat restriction, although traditional, is often unnecessary. It is best to be guided by the feelings of the patient. The patient can take as much fat as he can tolerate without feeling heaviness or nausea.
In short, no major restriction is really necessary. Since the patient already has loss of appetite and a foul taste in the mouth, traditional restrictions on diet only serve to make the patient malnourished. It is now considered best to let the patient have what he likes.142
5.73 If restrictions there must be some, let the patient avoid alcohol and strong spices. Alcohol is the single most important substance to avoid to prevent long-term damage to the liver.
5.74 In spite of all efforts, it may still be difficult to provide adequate quantity of balanced diet to a patient with acute hepatitis. On the other hand, vitamin requirement is enhanced under stressful conditions. Based on these reasons, it is customary to give vitamin supplements, specially B-complex tablets, to the patient. These are harmless, may be useful, and a safe thing to prescribe in practice.
5.75 In chronic liver disease, for example cirrhosis, the patient may be oedematous. In such cases, the generally liberal approach to diet, as discussed for hepatitis, holds good, but with a few reservations. For oedema, sodium should be restricted to about 1 g per day, as discussed for congestive 143heart failure. Fluid should also be restricted. Since oedema of chronic liver disease may be partly due to hypoalbuminaemia, albumin administration may be required in severe cases. If oesophageal varices are present, small morsels of soft, well cooked food should be chewn well to avoid hurting the varices. Tea, coffee, spices and alcohol should be avoided to reduce acid secretion. Antacids may be helpful. If cirrhosis is associated with diabetes, as is often the case, the dietary treatment should be altered accordingly.
5.76 Another disease which may be associated with oedema is renal disease. But the situation here is even more complex than in congestive heart failure or hepatic failure. The treatment, including dietary management, has to be individualised depending on whether the renal failure is acute, subacute or chronic, and which stage of the disease the patient is at.144
5.77 We shall talk mainly about fairly advanced chronic renal disease. Energy intake of such a patient should be adequate to meet the requirements. Proteins yield nitrogenous breakdown products which have to be excreted by the kidneys. Hence, to reduce the workload of the kidneys, proteins should be generally limited. The degree of restriction depends on the severity of the disease, and some patients may have to be put on as little as 25 g protein per day. As in case of liver disease, protein should be of good quality so that it is optimally used for protein synthesis instead of being broken down. Adequate energy intake also helps in conserving protein for synthetic functions. Since the protein intake is reduced, the other energy-giving nutrients have to be increased to provide adequate energy. Thus the diet generally given to a patient with chronic renal disease is a low protein, high carbohydrate, high fat diet.
5.78 The practical shape that such a diet takes is one in which most of the protein comes from milk, curd, cheese and egg. Some high carbohydrate foods which can supply energy without much associated protein are arrowroot biscuits, cornflour preparations, sago vada, sago khichri, sugar and glucose. Laddoos made from butter and sugar are a palatable preparation suitable for renal disease.
5.79 However, there are some important exceptions to these general principles. If the patient is on dialysis, extra protein has to be provided to compensate for protein loss at each dialysis. Depending on the type of dialysis and its frequency, the patient may need 1 to 1.5 g protein per kg body weight per day, about half to two-thirds of it of high biological value.
Second, if the patient is losing protein in the urine, as in nephrotic syndrome, again, a high protein diet is appropriate. Some physicians prescribe up to 150 g protein per day, but there is no agreement whether such high intakes are entirely beneficial.
5.80 Fluid intake should be guided by the loss, which can vary enormously with the type and stage of renal disease. What is important is that the intake should equal the loss. To achieve this, two things are helpful—an intake-output record, and daily body weight record.
Sodium generally needs to be restricted as in all other cases of oedema. However, some knowledge of sodium balance, such as serum and urinary sodium should be used for final guidance because in some stages of renal filure, sodium loss may actually exceed normal. Further, sodium administered in other forms, such as sodium bicarbonate for acidosis, should also be taken into account while deciding sodium intake.
5.81 Some potassium restriction is also generally required. Potassium is present in almost all foods but is specially rich in high protein foods. If protein intake is restricted, as is often the case in renal disease, potassium intake automatically gets restricted.
Because of the impaired ability of kidneys to excrete phosphorus, some phosporus restriction is also commonly necessary in chronic renal disease. Like potassium, phosphorus intake can also be reduced by reducing protein 147in the food. However, in some cases phosphorus binders may be required to reduce phosphorus absoption.
5.82 If the patient has hypercholesterolaemia, as in nephrotic syndrome, dietary cholesterol intake should be reduced. In the Indian context, this basically means avoiding yellow of the egg.
Vitamin supplements are customary, and probably necessary in view of the restricted diet and stressful situation.
Mineral supplements are also sometimes given. Iron needs special attention if the patient is on dialysis because of the blood loss entailed in dialysis.
Fibre supplementation, e.g. with ispaghula husk, may be required to keep the bowel moving in spite of the restricted diet.
5.83 Now we come to an ailment for which every patient wants dietary treatment while, in fact, diet helps very little, if at all. Urinary stones may be composed of dietary constituents like calcium, oxalates, uric acid or cystine. Therefore, one may be tempted to assume that a calcium stone in the urinary tract may disappear simply by taking a low calcium diet. However, such wishful thinking does not usually materialise.
5.84 Diet may, however, have some role in prevention of urinary calculi. The single most important measure in this respect is to take plenty of water. Less of water makes the urine concentrated. Salts are more likely to precipitate and form calculi in a concentrated solution. A dilute urine is safe not only from the point of view of calculi but also from that of urinary tract infections. Microorganisms also grow and multiply better in a concentrated urine. Therefore, the simple device of drinking plenty of water helps in avoiding two common and potentially dangerous ailments of the urinary tract—stones and infection.
5.85 For treatment also, if diet has to be tried for whatever contribution it can make to dissolving urinary 149calculi, the most important measure probably is plenty of water. It is often quite easy for the patient to drink plenty of water during the day, but at night the urine is apt to get concentrated. Hence the patient should be specifically instructed to take two glasses of water at bedtime, even if it means some disturbance in sleep.
5.86 The efficacy of low calcium, low oxalate, low purine or low methionine diets for stones of different composition is highly doubtful. When surgical removal of the stone was the only treatment available, giving a try to dietary modification still had some attraction. But now that non-invasive methods of treatment such as lithotripsy are available, the highly uncertain and usually ineffective dietary restrictions do not make much sense.
5.87 A low-purine diet is advocated also for gout, which is associated with hyperuricaemia. The role of a low purine diet in gout is also doubtful especially because now we know that dietary purines are not the only source of uric acid in the body. Uric acid is formed in the body also from endogenous purines, and simple substances such as carbon dioxide, glycine and ammonia.
5.88 However, it is good to know what foods to avoid in a low purine diet. In the Indian context, it is rather easy to have a low purine diet. The high purine foods are glandular meats and a few fishes. These foods are generally not taken regularly in India. Whole cereals and pulses have a moderate purine content but it may not be prudent to replace them wholesale by refined grains. Perhaps the quantity of whole pulses could be reduced. A few vegetables, namely beans, cauliflower, mushrooms and spinach also have a moderate purine content, and may be avoided. Other vegetables and fruits may be taken in an unrestricted amount. Milk, cheese and eggs have a negligible purine content. Butter and sugar also need not be restricted in the diet from the point of view of purines.151
5.89 Perhaps the single most important dietary measure for gout also is to drink plenty of water. Water helps in the excretion of uric acid. Tea, coffee and chocolates were also once eliminated from the diet in gout. These foods contain methyl xanthines which are metabolised to methyl urates. But now we know that methyl urates are not deposited in joints and other tissues. Hence tea and coffee also need not be restricted from this point of view. In general, patients seem to do better on a high carbohydrate, low protein, low fat diet, which is what an average Indian diet is. The effect of alcohol on gout is controversial, but certainly there is no harm in avoiding it. The availability of drugs which are quite effective in increasing the urinary excretion of uric acid and inhibiting its production has reduced the importance of diet in treatment of gout.
5.90 In contrast to the renal calculi and gout are some inborn errors of metabolism where diet is the major and most essential part of the treatment. The best known of these disorders is phenylketonuria. Because of the inability of these individuals to convert phenylalanine into tyrosine, they need a low phenylalanine diet, and of course adequate preformed tyrosine. But the main concern is to reduce phenylalanine in the diet. How difficult this can be may be realised from the fact that almost every dietary protein has phenylalanine, and a protein-free diet is incompatible with life. What is done in practice is to reduce the quantity of protein in the diet, and to allow only those protein containing foods, the phenylalanine content of which is low. It is easier to talk about what such a diet may contain rather than what foods should be avoided. The main sources of protein in the diet are rice, a small quantity of dal and some buffalo or goat milk and milk products. The accent is on high carbohydrate foods such as sago, cornflour, custard, sugar and jam. Vegetables, fruits and fats also need not be restricted from the point of view of phenylalanine. As you would observe, this diet has scrupulously avoided not only high protein foods such as meat, egg and cheese, but also cereals other than rice. The reason for this is the higher tyrosine content of rice protein as compared to protein from other cereals. The reason for preferring buffalo and goat milk to cow‘s milk is the relatively higher phenylalanine content of cow‘s milk.153
5.91 Another well-known inborn error of metabolism is galactosaemia. Since an individual with galactosaemia cannot convert galactose to glucose, he should have a galactose free diet. The only source of galactose in the diet which is worth considering is lactose, which is present in milk and milk products. Taking a milk-free diet is not a major problem for adults. Hence the problem is essentially to bring up the child on a milk-free diet during infancy. Several substitutes are available. For non-vegetarians a chicken-based feed can be prepared from chicken, glucose, coconut oil and salts. The chicken is boiled soft, and minced with the other ingredients in a blender. The mixture has an energy density similar to milk.154
5.92 An alternative, suitable for both vegetarians and non-vegetarians, is based on rice and green gram. The rice and green gram are boiled together, and then mixed with the other ingredients in a blender. In addition to these mixtures, commercial soya-based infant formulae are also available. These milk-free alternatives are also useful in feeding infants having diarrhoea due to lactose intolerance. However, one should be sure about the diagnosis before switching a child from breast milk to a lactose-free diet because the decision is crucial for the welfare of the child. Breast milk is an ideal food with several advantages. To deprive a child of breast milk because of mistaken diagnosis would be a tragedy which should be avoided scrupulously.155
5.93 Finally, we come to nutrition in relation to surgery. Surgery is a period of emotional and physical stress resulting in release of corticosteroid hormones, the overall effect of which is catabolic. On the other hand, surgery involves tissue damage, which can heal only through anabolic processes. Further, immediately after surgery, when wound healing is going on, it is often not possible for the patient to eat well. Hence, it is important to build up the patient nutritionally before surgery.
5.94 The preoperative build up essentially consists of a high energy, high protein diet. Care is taken to ensure a good haemoglobin level through administration of haema-tinics. High doses of vitamin C are given because of its role in wound healing. Zinc may also be important in this respect. Adequate vitamin K nutriture is also important to ensure normal clotting so that there is no excessive haemorrhage during surgery. This is further checked by doing prothrombin time.
5.95 Postoperatively, the diet depends on the type of surgery. After minor surgery, normal or nearly normal meals may be tarted within 12 hours of surgery. But after relatively major surgery, initially the patient is on intravenous fluids. A day or two after surgery, when the patient feels ready to eat, and peristalsis has returned, as indicated by bowel sounds, clear liquids are given. The trend these days is to accelerate the progression to a normal diet as much as possible to facilitate wound healing and to reduce postoperative weakness and emaciation. But generally the patient goes through four stages: clear liquid diet, full liquid diet, soft semi-solid diet and normal diet.157
5.96 Clear liquid diet includes clear soup, strained fruit juice, gelatin or jelly and black tea or coffee. Sugar and salt may be added to these items as appropriate. Sometimes the patient enjoys sucking ice cubes, and this may be allowed in moderation.
5.97 Full liquid diet may include any soup, fruit juice, tea, coffee and aerated drinks, porridge and other starchy gruels made from refined cereals, milk, lassi, curd, plain ice cream and egg with milk.158
5.98 Soft semi-solid diet is a simple, easily digested, low fibre diet. It may include, besides the items in the full liquid diet, biscuits, bread, butter, soft boiled egg, khichri made with dehusked dal, soft-cooked vegetables and cooked stewed fruit.
5.99 In addition, vitamin and mineral supplements, as discussed preoperatively, can also continue postoperatively. Oral or gastrointestinal surgery may require special care in diet.159In some cases, preoperatively as well as postoperatively, elemental diets or total parenteral nutrition may be the only way to maintain satisfactory nutrition.
5.100 With this we come to the end of the diet-disease interaction as well as the present series on applied nutrition. Hope you found it useful and also enjoyed it. Thank you.
APPENDIX I: TAPE SLIDE PROGRAM: WHAT, WHY AND HOW?
Tape slide program (TSP) is an unconventional instrument of teaching. In some respects it is like a lecture illustrated by slides with the difference that instead of seeing the teacher speak, the students hear his recorded voice on a cassette player. But a TSP can be more than a lecture. By using his imagination and creativity, the teacher can make a TSP an interesting and thought-provoking instrument of self-learning.
ADVANTAGES OF TSP
The TSP has several advantages as compared to a lecture.
- The student can set the pace of learning. A slow learner can pause for reflection, or keep going back to a difficult portion repeatedly by rewinding the tape.
- Depending on the facilities available, the student can also choose the time and place of learning.
- The student can not only learn on his own, questions for self-assessment can also be built into the TSP.
- A TSP can be an excellent aid to revision.
- A TSP multiplies the reach of the teacher. He can impart knowledge to a larger number of pupils at several places for a long time, even when he is no more.
- A TSP saves time for the teacher. Although preparing a TSP takes quite a long time, once it is ready, it can be used repeatedly even in the absence of the teacher.
- A TSP is much cheaper than the video, is much simpler to prepare, and has almost all the advantages of the video.
LIMITATIONS OF TSP
Like every teaching tool, TSP has its own limitations.
- TSP is a one-way communication. The student cannot get the teacher's responses to his questions. TSP can pose a hurdle in the teacher-taught relationship, both intellectual and social. However, these limitations may be overcome if the teacher is present in the class while the TSP is running. If the students have a question, the TSP can be interrupted for a while.
- A TSP is ideal for only a small group of 8-10 students.
- Unlike the video or a live demonstration, a TSP cannot demonstrate movement.
However, some of these limitations can be overcome in multimedia presentations. They can be interactive rather than one-way, and animation may be used to create movement.
PREPARING A TSP
As in all creative efforts, the first step in the preparation of a TSP is to get the idea. The most suitable topics for a TSP are those not generally dealt with in textbooks, or some narrow topic to which one wishes to give special treatment with a personal touch. Once the subject matter is clear, one has to sit down and write the script. The script has two sections, text and slides.163
Text
Since the text has to be recorded on an audio cassette, its language should be conversational. However, use of pronouns should be minimised. This caution is particularly important for Indians, because we tend to make extensive use of ambiguous pronouns in our native languages. In real conversations, one can always clarify a misunderstanding, but not if the voice has been recorded on a tape.
Slides
In contrast with the language of the text, the language of slides should be sketchy or pictorial. Each slide should have very few ideas, preferably only one. The material on the slide should be reduced to a minimum. A rough test to ensure that a slide is not cramped is to hold it against light. It should be possible to read the material on a good slide without using a lens. General principles of format and ligibility remain the same even for slides made on Power/Point.
For the TSPs given in this book, work up to the stage described above has already been done. The next stage is preparation of the audio cassette and projection slides.
Recording
Recording needs, besides a cassette and a recorder, a silent room. Finding a silent room can be really difficult at any time of the day. The hum of the fan, the chirping of the birds, the door bell, the telephone bell, the shout of a neighbour, movement of furniture nearby, blaring of a horn, and many other unpredictable sounds can make the search for silence a struggle. The saving grace, however, is that first, all these sounds do not occur simultaneously, and second, the adverse 164effect of many disturbing sounds on the recording is not as bad as one thinks.
The ideal voice for a TSP is that of the teacher to whom the students are accustomed. Even if the teacher's pronoun-ciation is not perfect, some educationists consider it more effective for teaching than a hired professionally perfect voice.
The best way go get one's natural voice on the tape is to avoid recorder consciousness. Although one is reading from a script, the voice should convey the impression of a lecture being delivered without notes by a friendly teacher. Getting that informality into the voice while reading the script needs a constant reminder within. A few rehearsals help, and are worth the effort.
During the recording, leave sufficient pauses for change of slides. It is better to provide an indication for change of slide in the form of a bell. In addition, with some sophisticated instruments, 1000 Hz pulses can be added at the points at which a change of slide is required. With these instruments, which combine a recorder and player with a slide projector, the pulse actuates a mechanism for an automatic change of slide. However, these luxuries do not necessarily add to the educational value of a TSP. An ordinary cassette player, which is a ubiquitous domestic appliance, is perfectly satisfactory.
Making Slides
The material for slides is available in this book in a camera-ready form. Most medical colleges have a photography unit which makes slides. However, if that facility is not available, any competent photographer can do the job. For most of the illustrations in this book, negative slides (white on black background), which are the least expensive, should be satisfactory. For a few tables, which are per necessity a little cramped, positives (Black on white background) would be 165preferable. With some additional ingenuity, effort and expense, colourful effects can also be added.
Alternatively, the CD supplied with the book may be used for display on a computer screen (for small groups), for projection using a data projector, or for preparing conventional colour slides.
Once the audio cassette and slides are ready, the TSP is ready for use. All one needs is a cassette player and computer or projector, and of course, willing students166
APPENDIX II: UNITS OF ENERGY IN NUTRITION
The popular unit of energy is kilocalorie (kcal), often called simply Calorie (spelt with a capital C). Calorie and kilocalorie are primarily units of heat energy. One kilocalorie is the amount of heat required to raise the temperature of 1 kg of water from 14.5 to 15.5° C. Recently, joule has been adopted as the universal unit for all types of energy, including food or metabolic energy. One joule is the energy required to move a mass of 1 kg through 1 metre by a force of 1 newton acting on it. One newton is the force which imparts an acceleration of 1 m per sec per sec to a mass of 1 kg.
The relationship between calories and joules is as follows:
1 kcal | = | 4.184 KJ (kilo joules) |
1000 kcal | = | 4184 KJ |
= | 4.184 MJ (mega joules) | |
1 KJ | = | 0.239 kcal |
APPENDIX III: UNITS OF MEASUREMENT IN THE KITCHEN
The standard equivalents of measures commonly used in the kitchen are approximately as follows:
One glass | : | 200-250 ml |
One katori | : | 150 ml |
One cup | : | 125 ml |
One tablespoon | : | 15 ml |
One teaspoon | : | 5 ml |
Since the specific gravity of most liquid foods and curries is quite close to 1, in this context:
1 ml = 1 g food (approximately)
APPENDIX IV: CLASSIFICATION OF OBESITY
Objective criteria of obesity are controversial. One of the better accepted classifications, originally proposed by Garrow, is based on body mass index (BMI).
BMI = Weight/Height2
where weight is expressed in kilograms, and height in metres. Thus if a person‘s weight is 65 kg and height is 1.7 m,
BMI = 65/(1.7)2
= 65/2.89
= 22.5
The WHO (1998) classification based on BMI is as follows:
BMI | Class |
|---|---|
< 18.5 | Underweight |
18.5-24.9 | Normal |
25.0-29.9 | Preobese |
30.0-34.9 | Obese Class I |
35.0-49.9 | Obese Class II |
> 40.0 | Obese Class III |
However, since Indians on an average, for a given BMI have relatively less muscle mass and more fat than people in the West, it has been suggested that the cut-off point of BMI between normal weight and overweight for Indians should be 23 rather than 25.169
Bibliography
- DudejaV, MisraA, PandeyRM, DevinaG, KumarG, VikramNK. BMI does not accurately predict overweight in Asian Indians in northern India. Br J Nutr 2001;86:105–12.
APPENDIX V: ENERGY COST OF EVERYDAY ACTIVITIES
Our energy requirements depend on our energy expenditure, and over the long run, the two should be equal. Energy expenditure is primarily made up of the resting metabolic rate (RMR) and energy cost of activities, although the thermic effect of feeding also makes a small contribution. As a rough approximation, RMR is 1 kcal/kg body weight/h. If the energy cost of an activity is 3 kcal/kg/h. the person spends 4 kcal/kg/h during the activity because resting metabolism continues even during the activity. Thus, the energy expenditure during this activity is four times the RMR. This is expressed by saying that the activity is associated with an energy factor (EFACT) of 4.0 (Mulligan & Butterfield, 1990). The EFACT value reflects the energy expenditure during each activity, expressed as a multiple of RMR. The EFACTs of some common activities are given below.
ACTIVITY | EFACT |
|---|---|
Sedentary ‘activities’ | |
Reading silently | 1.1 |
Resting | 1.1 |
Sleeping | 0.9 |
Very light activities | |
Cooking | 2.5 |
Desk work | 1.4 |
Dressing/undressing | 2.0 |
Driving (car) | 2.0 |
Eating | 1.5 |
Playing violin | 1.4 |
Reading aloud | 1.5 |
Sewing/stitching/tailoring | 1.5 |
Standing still | 1.4 |
Talking | 1.2 |
Typing | 1.7 |
Walking (3 km/h) | 2.0 |
Walking upstairs (1.5 km/h) | 2.0 |
Walking downstairs (3 km/h) | 2.5 |
Watching television | 1.4 |
Writing | 1.5 |
Yoga | 1.4 |
Light activities | |
Driving (motor cycle) | 3.0 |
Ironing | 3.0 |
Lab work | 3.0 |
Sex | 3.0 |
Walking (5 km/h) | 3.5 |
Moderately heavy activities | |
Cycling (10 km/h) | 5.0 |
Gardening | 4.0 |
Golf | 5.0 |
Walking (6 km/h) | 4.0 |
Heavy activities | |
Mountain climbing | 8.0 |
Rowing (6 km/h) | 8.0 |
Rowing (18 km/h) | 12.0 |
Running (10 km/h) | 10.0 |
Running (15 km/h) | 15.0 |
Running (25 km/h) | 50.0 |
Squash | 10.0 |
Swimming (3 km/h) | 9.0 |
Table tennis | 6.0 |
Tennis | 8.0 |
Walking (8 km/h) | 9.0 |
Walking upstairs (3 km/h) | 7.0 |
Based on data from multiple sources. Figures have been rounded off for convenience. In cases of varying figures from different sources, compromise figures have been given.
Let us see how these figures can be used for calculating the energy expenditure of a 60 kg man.
Acitivity | EFACT | Duration (h) | EFACT × Duration |
|---|---|---|---|
Sleeping | 0.9 | 8.0 | 7.2 |
Desk work | 1.4 | 6.0 | 8.4 |
Reading silently | 1.1 | 1.0 | 1.1 |
Driving motor cycle | 3.0 | 1.0 | 3.0 |
Walking (3 km/h) | 2.0 | 0.5 | 1.0 |
Dressing and undressing | 2.0 | 0.5 | 1.0 |
Eating | 1.5 | 1.0 | 1.5 |
Reading aloud to children | 1.5 | 1.0 | 1.5 |
Talking | 1.2 | 1.0 | 1.2 |
Watching television | 1.4 | 3.0 | 4.2 |
Tennis | 8.0 | 0.5 | 4.0 |
Resting | 1.1 | 0.5 | 0.5 |
Total | 24.0 | 34.6 |
RMR = 1 kcal/kg/h
∴ Daily energy expenditure of the 60 kg man = 1 × 34.6 × 60 kcal
The ratio Total Energy Expenditure/Basal (or Resting) Metabolic Rate is called the Physical Activity Level (PAL). In the above example, it is 34.6/24.0 = 1.44. The UN agencies (FAO/WHO/UNU) have recently proposed a classification of lifestyles based on PAL as follows:
PAL | Lifestyle |
|---|---|
1.4–1.69 | Sedentary |
1.7–1.99 | Active |
2–2.39 | Vigorously active |
Further, they have recommended that the PAL be maintained at the level of 1.75 or above throughout life for optimal health.
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