Human resources section6-textbook_on_public_health_and_community_medicine

3,518 views

Published on

AFMC WHO Textbook Community Medicine

Published in: Health & Medicine
  • Be the first to comment

Human resources section6-textbook_on_public_health_and_community_medicine

  1. 1. 10095752550
  2. 2. Section 6 : Nutrition in Public Health127 Introduction to Nutrition in Public health Rajul K Gupta 712128 The Proximate Principles and Energy Rajul K Gupta 717129 Micronutrients : The Vitamins Rajul K Gupta 725130 The Micronutrients : Minerals Rajul K Gupta 734131 Major Foods and their Nutritive Value Rajul K Gupta 741 Nutritional Requirements of Special Groups:132 Rajul K Gupta 750 Mothers, Children and the Elderly133 Nutritional Deficiency Diseases of Public Health Importance Rajul K Gupta 758 Public Health Aspects of Food Hygiene & Sanitary134 Rajul K Gupta 771 Regulation of Eating Establishments135 Nutritional Programmes in India Rajul K Gupta 778136 Nutritional Assessment and Surveillance of a Community Rajul K Gupta 783 Food Processing, Food Adulteration, Food Additives,137 Rajul K Gupta 791 Preservatives, Food Toxicants and Food Fortification Nutrition during Special Situations : Disasters, Fairs138 Rajul K Gupta 798 and Festivals, Community Feeding of Children139 Nutrition Tables Rajul K Gupta 804
  3. 3. therapeutic regimens. For instance, his dietetic prescriptions Introduction to Nutrition in 127 Public health reveal a close relationship of effects of individual foods on both sick and the well. Pulses, he said, should be eaten with cereals. The obese should be advised to labour much, drink little…. Rajul K Gupta Remedial foods have been suggested for fever, ‘hot intestines’, dysentery, melancholic disorders etc. (4, 5). Ancient Indian texts give adequate indication of the importance that diet andThe term ‘Nutrition’ is derived from a Latin word nutritic, nutrition were accorded during ancient times (Box - 2).meaning nourishment (1). Nutrition can be considered to be thefoundation of good health and freedom from disease. ‘Nutrition Box - 2 : Aahara, Vichara, Yoga and Ayurveda : Thescience’ has been comprehensively defined by Robinson as ‘The Ancient Indian wisdomscience of foods, nutrients and other substances therein; theiraction, interaction and balance in relationship to health and Aahara or the dietary philosophy has been central to thedisease; the processes by which the organism ingests, digests, concept of ancient Indian system of medicine, Ayurveda.absorbs, transports and utilizes nutrients and disposes off their Prudent food with a strict dietary discipline was theend products…” (2). Simply put the word nutrition is used to hallmark of ancient Indian lifestyle and one of the secretsrefer to the processes of the intake, digestion and assimilation of a long and healthy life which the Indians enjoyed in theof nutrients and the application of this knowledge to maintain Vedic times. As per the principles of Ayurveda, the diet ishealth and combat disease. See Box - 1. supposed to change with the time of the day and seasons. ‘Hot’ and ‘cold’ temperaments of the food are supposed to Box - 1 : Significance of nutrition be balanced with the weather, seasons and climate. These dictums were ingrained in the lifestyle along with good and Adequate nutrition is required for growth, development and noble thoughts (vichara) and the discipline of life (Yoga) for maintenance of normal functions a long lasting good health and the ultimate union with the Under nutrition contributes to 60% deaths amongst under supreme power. Can we learn something from this traditional five children (WHO, 2002) Indian wisdom! More than 85% children in India suffer from malnutrition (44% Mild malnutrition, 38% moderate malnutrition and 4.6% The phrase ‘science of nutrition’ was first used probably by Count severe malnutrition) (Gomez classification, NNMB 2007) Rumond in an essay on feeding poor people in 1795 (6). During the same period Lavoisier who was working on combustion and About 55% men and 75% non pregnant non lactating women respiratory metabolism, is said to have established nutrition as are anaemic a science (7). In 1753 James Lind published the first edition of Epidemiological data shows strong association between A Treatise on the Scurvy which elaborated how 110 men were under nutrition and morbidity / mortality disabled by scurvy and were miraculously cured by an Indian Chronic degenerative disorders such as coronary artery remedy (the infusion of the needles of an evergreen tree). Lind disease, hypertension, type 2 diabetes, certain cancers, etc was also the first one to study experimentally the value of are related to diet and nutritional status different substances in the treatment of scurvy, and proved that dietary lemons and oranges cured scurvy (5). Obesity is associated with higher risk of developing cancer In 1839, a Dutch physician Gerrit Mulder claimed that complex breast, colon, endometrium, gallbladder, esophagus, nitrogen compounds like egg albumin, serum albumin, fibrin pancreas, etc. and wheat gluten all contained a common radical, ‘protein’ (8). Consumption of foods rich in dietary fibre and antioxidants Marasmus was described in the year 1877 by Jules Poirot from is associated with reduced risk of certain cancers France under the term “athrepesie”. Under nutrition during foetal and early childhood is known The science of nutrition bloomed during the 20th century. to be associated with chronic degenerative disorders in later Vitamins and amino acids were discovered, human nutritional life requirements were established and the relationship between diet, nutrition and the human body in health and disease wereGood nutrition is a fundamental requirement for positive recognized. These scientific advances evolved through severalhealth, functional efficiency and productivity. Nutritional phases. Lafayette B. Mender (USA) identified the nutritivestatus is internationally recognized as an indicator of national value of proteins during 1909-1928. In due course, variousdevelopment. Nutrition is both an input into and an output of, experiments and observations by different workers pointedthe developmental process (3). towards some unknown food factors that were vital for theNutrition is an extremely dynamic subject that changes every very sustenance of life. JBA Dumas (1871) was the earliest manday. Continuous research and a constant study into nutrition of science to question the adequacy of diet composed only oftherefore remains a subject of contemporary interest. proteins, carbohydrates, fats and salts. He had published his observations on the health of infants of Paris made during theHistory siege by the Germans. Pekelharing demonstrated in 1905 theIt is believed that Hippocrates, the Father of Medicine, paid existence of unidentified nutrients in milk and why they werestrict attention to the diet of his patients as a feature of his absolutely essential for survival of mice in minute quantities. • 712 •
  4. 4. In 1912 Casimir Funk (Poland) propounded the theory that research on animal nutrition, communicable disease andberiberi, scurvy, pellagra and possibly rickets were caused food safety. The bird flu endemic has once again opened theby deficiency of “special substances which are of the nature Pandora’s Box : ‘Are the non-vegetarian foods safe enough?’of organic bases” and coined the term ‘vitamine’. Thus the (9). Fierce research is on, to answer these questions throughnew concept of dietary deficiency diseases was born. In 1926 the integrated effort of multidisciplinary forces… medicine,Goldberger and Lillie described malnutrition in rats also virology, veterinary medicine, nutrition, food technology, publicfeaturing growth arrest, ‘ophthalmia’, hair loss on ears, neck, health, epidemiology, genetics, biotechnology, mathematicalchest and forearms etc. Fur became matted and fell exposing modelling, information technology…. These and many otherdenuded pale pink skin. Oral and lingual ulcers and fissuring advances in nutritional sciences represent the ceaseless effort,were also noticed. Diarrhoea was also seen in some rats. The genuine initiative and devotion of many pioneer scientists allcondition was diagnosed as rat pellagra. Lean meat and yeast over the world through out the ages.cured it. The curative agent was designated by Goldberger and Food and Nutrients : Major Categories of Foods andLillie as pellagra-preventive (P-P) factor. However, later it was Nutrientsfound that this condition (in rats) was not analogous to humanpellagra, but was caused due to the deficiency of riboflavin. Food : Food is a substance eaten or drunk to maintain life and growth. The foods are generally classified into cereals (wheat,The dangerous disease Pellagra was earlier described in rice, maize etc.), legumes (pulses and peas), nuts and oilseeds,Northern Spain in 1735 by Casal. However, scientific world had vegetables, fruits, milk and milk products and flesh foods (fish,to wait till Goldberger undertook a study in 1915. He studied meat and chicken and egg). Diet, on the other hand is what athe diets of patients and medical staff in State Asylums in person habitually eats and drinks.South Carolina, Georgia and Mississipi. This study proved thatthe disease was caused by a deficiency rather than a poison Nutrients : The nutrients are chemical substances thator infection. The search for the pellagra preventing factor are present in the food we eat. The important nutrients aretravelled through high proteins, yeast and liver and ended with proteins, fats, carbohydrates, vitamins and minerals. Foodsthe isolation of nicotinic acid from rice polishings by Funk in contain various nutrients in different proportions. Depending1912. Many other workers also isolated this chemical from on the relative concentration of various nutrients foods can beother food stuffs (5). classified into protein, carbohydrate or fat rich foods.Verner McCollum (USA) discovered a fat soluble soluble factor Why do we eat food? - Functions of food : We eat to satisfythat was essential for growth (Vitamin A) in l916 (6). Chick, hunger (satiety) and to get energy for our day to day functioning.Windaus and Hess worked on Vitamin D, Evans and Bishop Food serves many functions in the body :on Vitamin E, King and Gyorgy on Vitamin C, Dam on Vitamin a) Food builds body tissues : The structural materials of food,K, Mitchell, Snell and Williams on folic acid and Hodjkin on proteins, minerals, vitamins and water are needed for growthVitamin B. and development. The food is also needed for the maintenanceMcCance, Mac Kay, Widdowson, McLaren and Woodruff did of the cells and tissues.pioneering work on iron deficiency. Ciceley Williams (England) b) Food regulates body processes : Many a body processesdescribed Kwashiorkar in 1933. Kerpel Fronuis, Gomez and are regulated by the ‘fuel’ supplied through food e.g.Cravioto also worked on protein calorie deficiency. temperature control of the body (calories), control of osmoticGreat debate started in the sixties and seventies on the causation pressure (proteins and electrolytes), maintenance of hydrogenand relationship between marasmus and kwashiorkor where ion concentration (pH through electrolytes), solvent powereminent nutritional scientists, Waterlow, Gopalan, Scrimshaw, of fluids (proteins and water), nerve conduction (minerals),McLaren and others participated. Various studies on protein muscle elasticity (minerals), innumerable metabolic processesand energy requirements, the role of infection, metabolic and (vitamins and minerals).endocrine changes, and adaptation were carried out. Derrick c) Food supplies energy : The macronutrients (carbohydrates,Jelliffe, a pioneer in nutrition introduced the term ‘protein- proteins and fats) supply energy. These provide constant sourcecalorie’ malnutrition, which was later modified to protein of fuel to the body. It is measured in terms of a kilo calorie.energy malnutrition and adopted by the FAO/WHO committee d) Food gives us enjoyment : We want to enjoy food andin 1971 to describe both kwashiorkor and marasmus. entertain our guests with tasty food.Into the 21st century : The era of interdisciplinary These requirements may be met by various combinations of thecoordination three major food constituents : carbohydrates, proteins & fats,Agriculture cannot be kept away from nutrition. Great advances taken in different proportions. Although the actual distributionin agriculture were achieved with the green revolution in of each one of these nutrients in our daily diet is vital forIndia. The introduction of genetically engineered food during good health, one hardly considers their proportion, as long asthe last decades of the twentieth century was followed by an he enjoys the food. It must be appreciated that our lifestyleongoing international scientific debate. Parallel advances were governs all facets of our life including our eating habits.achieved in animal nutrition and veterinary medicine, which The community faces major nutritional problems from theincreased animal food production. The relationship between consumption of inadequate or imbalanced diet. This is truemad cow disease and animal food as well as its relationship to for both healthy and sick. Economic prosperity and affluence,Cruetzfeld Jacob disease in the humans is stimulating further at least in a section of the society, are now threatening the • 713 •
  5. 5. community through over nutrition and its related hazards. attacks of acute respiratory or acute diarrhoeal infections areFrom Under-Nutrition to Over-Nutrition notorious to lead to a malnourished state. Measles is another dangerous condition that has a lasting negative effect onWithin the past few decades, there has been a significant the system through compromised immunity, micronutrientreduction in cases of nutritional deficiencies. Classical deficiency and severe malnutrition.nutritional deficiency syndromes of florid pellagra, beriberi,scurvy or kwashiorkor have almost disappeared. We do not Malnutrition in childhood diminishes the proper developmentcome across the famines any more. This improved scenario is a of the immune response mechanism. The cellular immuneresult of multiple inputs namely, smaller families, better food responses are markedly impaired leading to a higher mortalitysecurity, economic development, improved health systems, from the seemingly common infections.conquest of infections, better health awareness and accountable Variability in Nutritional Requirementsgovernance. It is seen that malnutrition among preschoolers Even though there is a concept of standard requirements andhas reduced appreciably and nutritional status of adults too intakes, it must not be forgotten that each person has uniquehas improved significantly. There is not only a major reduction nutritional requirements. This is because each one of us hasin malnutrition, but over the past decade or so we have stepped a unique genetic make up and body biochemistry. A nutrientinto the realm of over nutrition. The number of overweight intake sufficient for one person may be inadequate for other.and obese is steadily and alarmingly rising in India. This is There are many references in literature where it is quoted thatowing to the rapid lifestyle changes that have swept India. where 2 mg Vitamin B6 is normally adequate for most but thereMechanization, motorization, static entertainment (television are individuals with inherited defects in B6 metabolism andand computers), sedentary life, low physical activity and the need 30 to 100 times that amount. Similarly the absorptionfast food culture has taken its toll. The situation is so alarming and daily requirements of Calcium varies 3 to 5 folds in variousthat there is a recommendation to redrawn BMI standards with normal individuals. The same can be said for Vitamin D anda more stringent ‘pen’, in a hope to stall the rapid progression Iron where metabolic differences in handling these nutrientsof lifestyle diseases - diabetes, hypertension and the coronary alter their requirement.artery disease. Besides these genetic differences, many other factors can alsoThe Interplay between Malnutrition and Infection alter daily requirements, including age, environment and lifeThere has been a close association between malnutrition and style choices. Factors as diverse as pregnancy, lactation, sportsinfections (Fig. - 1). It is a vicious cycle that is difficult to training, smoking and pollutants can cause nutritional needsbreak in the setting of poverty, ignorance and lack of health to vary. Some of these factors are summarized in the Box - 3.services. Box - 3 : Factors altering the daily requirement of Fig. - 1 : The vicious cycle of malnutrition and infections nutrients Severe Biochemical individuality Genetic differences Malnourishment Gender Pregnancy Lactation Growth Nutrients: Increased Infections Other diseases Extra need & metabolic rate & tissue Poor supply Surgery Drug-Nutrient interaction damage. Low immunity Smoking Alcohol Caffeine Environmental pollutants Activity Exercise level Diet factors e.g. intake of : Carbohydrates; Fat; Fibre; Proteins In GI infections Need for extra nutrient absorption nutrients and Dietary Standards : Concept of Recommended Dietary diminished also reduced Allowance (RDA) appetite It is extremely important to plan the rations and food supplies for various groups, may it be the general community or aLet’s take fever as an example. The raised temperature escalates specialized group like the armed forces, a school or a prison.the metabolic rate and thus increases the nutritional demand; For such a planning we must have a set of standard allowancesit also increases the tissue breakdown further putting an extra that are universally acceptable and followed. The first suchnutritional load on the system. In almost all infections the example (for cereals) can be traced back to ancient Rome (seeappetite goes down and the absorption and assimilation is also Box - 4). The concept of various macro-nutrients first evolvedhampered. The requirement of nutrients is increased and to make in the nineteenth century. At that time the dietary requirementsmatters worse, the supply is diminished and the absorption is were stated in terms of nutrients rather than foods. In the earlyreduced. The body can cope up with this situation for few days twentieth century vitamins came on the landscape and theirbut subsequently acute severe malnutrition develops. Repeated requirements were also worked out and stated (10). • 714 •
  6. 6. keeping the RDAs in mind. Box - 4 : The Roman Pound of Wheat The concept of recommended allowance for the day probably Reference Man and Woman came from the Romans. The Romans gave their legionaries The final goal of all nutritional policies and recommendations a ration of one ‘librum’ of wheat per day and that was at a national level is to provide adequate nutrition to its supposed to meet their caloric requirement for the day. The population in order to attain their full genetic potential ‘librum’ became the British Pound (abbreviated to and still of growth and development. It is important that the ideal/ used as ‘lb’). One pound of cereal is now known to be good desirable weights and heights are considered to recommend enough to provide energy needed for an adult man for resting nutrient intakes. For this purpose the ICMR expert committee metabolism. recommended reference weights for adult men and women to be 60 Kg and 50 Kg respectively.Recommended Dietary Allowances or Intakes (RDA or Reference Indian Adult Man : Reference Indian adult man isRDI) between 20-39 years of age and weighs 60 Kg. He is free from The RDA of a nutrient is the amount (of that nutrient) sufficient disease and physically fit for work. On each working day hefor the maintenance of health in nearly all people (11). In is employed for 8 hours in occupation that usually involvesother words these are the estimates of nutrient intakes which moderate activity. While not at work he spends 8 hours in bed,individuals in a population group need to consume to ensure 4-6 hours sitting and moving about and 2 hours in walkingthat the physiological needs of all subjects in that population and in active recreation or household duties.are met. It is an estimate that corresponds to mean intake of Reference Indian Adult Woman : Reference Indian adultthe given nutrient + 2 Standard Deviation (that is about 25% of woman is between 20-39 years of age and healthy; she weighsthe mean has been added). It covers the requirement of 97.5% of 50 Kg. She may be engaged in general household work, in lightthe population. This is the safe level of intake and the chances industry or in any other moderately active work for 8 hours.of this level being inadequate is not more than 2.5%. This ‘safe While not at work she spends 8 hours in bed, 4-6 hours sittinglevel’ approach is however not used for defining the energy and moving about in light activity and 2 hours in walking orrequirement, as any excess of energy intake is as undesirable active household chores.as its inadequate intake. Hence for defining the RDA of energy Energy requirements for sedentary, moderate and hard workonly the average requirement is considered. The recommended (12) : Energy requirements of an individual vary over a widedietary allowances for Indians are summarized in Table - 1 in range depending upon the sex, age, body size, BMR and degree‘Chapter on Nutritional Tables’. of physical activity. As it has been discussed earlier, energyCan the RDA be Applied to Individuals? requirements are given in terms of a Reference man/woman. Energy requirements for other individuals with differentIt must be appreciated that the RDA is the mean requirement weights and age have to be calculated.figure for a nutrient (except energy), to which an allowancecorresponding to 2 SD has been added. There are several The classification of physical activity as sedentary, moderateindividuals in a population whose requirement is actually well and heavy is essentially based on the occupational activity.below or above the RDA. If all the students in a class of 100 Some more examples are given in the Box - 5. The energywere to eat food exactly as per their RDA about half would loose requirements for these three categories are summarized inand the other half would gain weight, to the extent of being Table 1.seriously undernourished or obese after a year! It is becausethe RDA for energy is a catering average; individuals however Box - 5 : Some examples : Sedentary, moderate and hardconsume as per their appetite, which follows their energy workersexpenditure. The RDA can therefore, not be used as standard Sedentary worker : Teacher, tailor, barber, priest, executive,to determine whether or not a given individual’s requirement peon, retired personnel, shoe maker, housewife, maid, nurse,of a nutrient has been met. It is therefore important to keep doctor, clerk, shopkeeper, manager, goldsmith etc.the principles of probability in mind and be cautious, when Moderate worker : Potter, basket maker, carpenter, mason,applying RDA at an individual level (10). electrician, fitter, turner, driver, welder, fisherman, coolie,RDAs provide a standard against which the nutrients in the food site supervisor, post man etc.eaten by a section of the community /country can be assessed. Heavy worker : Stone cutter, blacksmith, mine worker, woodIt is thus possible to find out a group with a low intake of a cutter, farm labourer, army soldier etc.particular nutrient. Further nutritional investigations are thenmounted to go into the details and suitable measures can berecommended. As discussed earlier, RDAs should not be used to Table - 1 : Energy Requirements of Reference Indian Manassess the diet of an individual patient as they are designed to and Womanbe on the higher side than the average individual requirement. BodyWhenever diets are required to be planned for a group like the Sex Activity levels weight (Kg)armed forces, a school, hostel etc., the diet should meet the Sedentary Moderate HeavyRDA. Similarly, RDAs are the starting point for the food andeconomic planning for the agricultural, economic and food Male 60 2425 2875 3800sectors. The national level food balance sheets are prepared Female 50 1875 2225 2925 • 715 •
  7. 7. Prevention of Nutritional Disease and Upkeep of Government level : The responsibility of maintaining the healthNutrition in the Community - Role of Individuals, of individuals lies with the state. The government endeavorsFamily, Communities and Governments to provide all the health services possible. Various nutritional programmes are being implemented as direct intervention toIt can be well appreciated that it is not merely the ‘nutritional’ improve the nutritional status of the community. Noteworthyfactors that are responsible for nutritional disease. These of these are the ICDS Programme, Balwadi nutrition programmeconditions are truly multi-factorial in origin and progression. and the Special Nutrition programme under the Ministry ofThe scarcity of food, its nutritional value, distribution, balance Social welfare. Ministry of Health and Family Welfare runs thein diet, cultural, local and religious factors and beliefs, other Nutritional anaemia prophylaxis programme, Iodine deficiencysocial factors like ignorance, poverty, taboos, fads, peer pressure, disorders control programme and the Vitamin A prophylaxiseducation, hygiene and sanitation practices, infections, programme. The Mid Day Meal programme (for primaryavailability of health services, level of immunization services, children) is being run by the Ministry of Education.political will, corporate interests, national commitment,international influences like trade laws and treaties, export- Besides these various indirect measures are being taken byimport dynamics and compulsions, inter country relations, the the government for rural development, increasing agriculturalstate of global warming - each one of these have a bearing production, population stabilization and improving the publicon the nutritional status of a society. When the etiology is so distribution system. Research in the field of nutrition is beingdiverse, the prevention too has to be so much broad based carried out at premier institutions like the National Instituteand multifaceted. The issue can be tackled at the levels of the of Nutrition at Hyderabad that has contributed to offeringindividual, family, community and governments. solutions to nutritional problems.Individual level : Health begins with the individual. The Summaryindividual has to take care of himself. Selecting the correct kind The science of foods and nutrients and their action, interactionof food is vital, based on his age, physiological state, taste and and balance in relationship to health and disease; the processestradition. Besides good diet, physical activity, adequate sleep, by which the organism ingests, digests, absorbs, transports andmental peace and appropriate meditative or religious activities utilizes nutrients and disposes off their end products is termedgo a long way in keeping an individual healthy. Knowing the as nutrition. Good nutrition is a fundamental requirementnearest health centre, services available there and warning for positive health, functional efficiency and productivity.signs of common illnesses is also important. There has been a close association between malnutrition andFamily level : Most of the foods are ‘handed over’ to us infections. It is a vicious cycle that perpetuates in the setting ofthrough traditions, and it is not easy to break out of those. poverty, ignorance and lack of health services.Within that framework, it might be decided by the head of the The variation in the daily requirements of nutrients depends onfamily as to what food stuff is to be brought, cooked or eaten. the genetic differences, age, environment and life style choices.The family needs to be aware and educated on the issues of Factors as diverse as pregnancy, lactation, sports training,nutrition to select the correct foods in different situations smoking and pollutants can also cause nutritional needs toof infancy, childhood, pregnancy or lactation. This can vary. However a set of universally acceptable standard nutrienthappen only when they have risen above the myths, taboos, allowances have been devised that are useful to plan the rationsfads and misconceptions encompassing foods. Misleading and food supplies for diverse groups. The RDA of a nutrient isadvertisements must be put in the right perspective. Children the amount (of that nutrient) sufficient for the maintenance ofmust be explained the hazards of junk food and food additives. health in nearly all people. The RDA is based on the concept ofTraditional values with respect to food must be highlighted. Reference Indian man and woman.The family foods used during pregnancy, lactation and weaningmust be acknowledged. Locally available foods that are easily Study Exercisesavailable, cheap, fresh and suitable to a particular season Long Question : Discuss the role of individual, family,are ideal and must be consumed in preference to ‘imported’ community and government in the prevention of nutritionfoods. A small kitchen garden will go a long way not only in related diseases.appreciating good and wholesome food but also in fulfilling Short Notes : (1) Indian reference man (2) Nutritionalthe nutritional needs of the family in the most inexpensive and requirement of sedentary man (3) Malnutrition-infection cycleenjoyable manner. The most crucial nutritional decisions aretaken at the family level, so the family must be empowered MCQsthrough correct knowledge. 1. Who coined the term ‘vitamin’ : (a) McCollum (b) FunkCommunity level : There might be a number of bottlenecks that (c) Hopkins (d) James Lindexist at a local level which prevent the national programmes 2. A teacher will be classified as a (a) Sedentary workerreach the grassroot. It is up to the community to meet this (b) Moderate worker (c) Heavy worker (d) Average workerchallenge of making these programmes actually beneficial to 3. A ‘safety margin’ of + 2 SD is not incorporated for thethe people. For example the Gram Sabha, the local ICDS unit RDA of (a) Energy (b) Fats (c) Water soluble vitamins(Anganwadi) etc. must be aware of their rights and duties, and (d) Fat soluble vitaminswhom to approach in case of neglect. The community must be 4. Which of the following diseases is most notorious toorganized and ‘live’ up to these needs, otherwise they will have prove fatal in combination with malnutrition : (a) Tetanusto be satisfied with whatever is ‘served’ to them! (b) Anaemia (c) Measles (d) Diarrhoea • 716 •
  8. 8. 5. Choosing what type of food to eat in a household is the 5. Mc Collum EV. A history of Nutrition, Boston, Houghton Miffin Company, 1957. function of the (a) Family (b) Government (c) Community 6. Todhunter EN. Chronology of some events in the development and application (d) Any of the above of the science of Nutrition. Nutrition Reviews, 1976, 34 : 354- 375.Answers : (1) b ; (2) a ; (3) a ; (4) c ; (5) a. 7. Davidson S, Passmore R, Brock JF, Truswell AS. Human Nutrition and Dietetics. 6th ed. Churchill Livingstone, ELBS London. 1975.References 8. Mahan LK, Stump SL. Krause’s Food, Nutrition & diet therapy.11th edition1. Nix Staci. Williams Basic Nutrition and Diet Therapy. 12th edition. Mosby, Saunder’s Philadelphia, USA. 2000 Elsevier. Missouri, USA. 2005 9. Gabr M. IUNS in the 21st century on the shoulders of 20th century giants of2. Bamji MS, Rao NP Reddy V. Textbook of Human Nutrition. 2nd ed. Oxford & , nutrition. In : Modern Aspects of Nutrition, Present knowledge and Future IBH Publishing Co Pvt Ltd, New Delhi.2003. Perspectives. Eds Elmadfa I, Anklam E, Konig JS. 2003. 56 : 13-183. Report of the Working Group on Integrating Nutrition with Health for the 10. Davidson S, Passmore R, Brock JF, Truswell AS. Human Nutrition and XI Five Year Plan (2007-2012 Government Of India Ministry Of Women And Dietetics. Churchill Livingstone, ELBS London. 1986. Child Development November 2006. 11. World Health Organization. Technical Report Series no. 477; 1971.4. Hippocrates, the authentic writings of; Translated by Adams F. Wm Wood 12. National Institute of Nutrition, Nutritional requirements and recommended and Company., New York, 1929; Vol 1, 272-277 and Vol 2 42, 193-98. dietary allowances for Indians; A report of the ICMR, 2004. of internal organs and to maintain the body temperature. The Proximate Principles and 128 Energy This energy is required for maintaining the basal or resting metabolism. Age, sex, height, weight and state of nutrition of the individual are some of the factors that influence it. The Rajul K Gupta Basal Metabolic Rate (BMR) is determined experimentally when the subject is lying down at complete physical and mental rest, wearing light clothing in a thermo-neutral environment and inThe human body requires various nutrients for survival, the post absorptive state (at least 12 hours after the last meal).maintenance of health and to prevent disease. Proteins, fats, The BMR is related more closely to lean body mass (fat freecarbohydrates, vitamins, minerals and antioxidants are the body) rather than to the surface area. The reported value ofmost important of these. Proteins, fats and carbohydrates are BMR for Indians is 1 Kcal / Kg/ hr.the ones which form the backbone of the nutrients in termsof quantity and these are termed as the proximate principles Units of Energyof food. In order to appreciate the influence of food on health Calorie is the basic unit of energy. Kilo calorie is defined as theand the factors which affect food requirements, it is necessary heat required to raise the temperature of 1 Kg of water by 1°Cto know the chemical composition of food and its metabolism from 14.5°C to 15.5°C. The Joule (J) is the SI unit of energy. It isin man. The most primary function of food is to be broken defined as the energy expended when a mass of one kilogramdown in the body to generate energy, which is vital for the very is moved one meter by a force of one Newton (N). Since Joule issurvival of the body. too small a unit to describe the energy value of diet, kilo JouleEnergy for basal functions, work metabolism and heat for (KJ) and mega Joule (MJ) are of more practical use. One KJ ismaintenance of body temperature is produced by the oxidation equal to 1000 J and one MJ is equal to 1000 KJ. However, theof carbohydrates, fats and proteins. The intake of food is old unit of energy, namely, kilocalorie (Kcal) has been in usenormally balanced by hunger which thus, indirectly balances in nutrition for a long time and is still being used (1, 2). Forenergy expenditure. Hunger may, however, not indicate this conversion, 1 Kcal = 4.184 KJ and 1 KJ = 0.239 Kcal. Energyin various pathological states, notably in certain forms of contents of common food items are shown in Table -1 & 2 :malnutrition. Moreover, hunger can be modified not only byenough intake of food but also by doing less muscular work. ProteinsAbsence of hunger is not, therefore, necessarily an index of Proteins are large molecules made up of nitrogen containingan adequate food intake. Before going into the biochemical amino acids that are united together by peptide linkages. Inand physiological qualities of food let us dwell on the basics adults approximately 16% of body weight is attributable toof energy. proteins. Next to water, protein is the major component of body tissues. Proteins are indispensable constituents of livingEnergy protoplasm as they participate in all vital processes. ProteinsEnergy is required for maintaining the body temperature and are macromolecules consisting of amino acid chains. Thevital activity of organs, for mechanical work and for growth. human body has a limited capacity of converting one aminoacidEven when an individual is at complete rest and no physical into another (1, 4). A total of 22 aminoacids are now knownwork is being carried out, energy is required for the activity to be physiologically important for the human body. Under proper conditions, the body is capable of synthesizing some of • 717 •
  9. 9. Table 1 : Major contributors of energy to our diet - (Some Table 2 : Energy content of selected Indian food items raw foods and their energy content per 100g) (1) (per serving) (3) Energy Energy Food item Kcal Food item Kcal Food stuff Food stuff (Kcal) (Kcal) Samosa (1 no.) 256 Dalia (1 plate) 80 Cereals & Millets Non vegetarian foods Masala dosa (1 no.) 360 Khichri (1 plate) 160 Wheat flour 341 Egg (hen) 173 Kachori (2 nos.) 500 Biscuits (4 nos.) 150 Rice polished 345 Fish (Hilsa) 273 Omlette (1 egg) 236 Poha (1 plate) 120 Bajra 361 Chicken 109 Puri (4 nos. x 320 Bread (2 slices) 125 Maize dry 342 Mutton (lean) 118 25 g each) Ragi 328 Pork (muscle) 114 Chapati with ghee 360 Chapati ( 2 nos. 160 Pulses & Legumes Milk & milk products (4 nos.) x 35 g each) Bengal gram 360 Milk, cow 67 Cake (1 small piece) 250 Kheer (1 katori) 120 Soya bean 432 Milk, buffalo 117 Butter chicken 400 Cornflakes (1 bowl) 190 (1 katori) Rajmah 346 Milk, human 65 Chiken biryani 400 Veg salad 50 Redgram (Arhar) 335 Butter 729 (200 g) Greengram Ghee Malai paneer 270 Butter milk (1 glass) 90 334 900 (Moong) (1 katori) Lentil (Masoor) 343 Cheese 348 Paratha (2 nos. 360 Jam (1table spoon) 40 Pea dry 315 Curd 60 x 50 g each) Fruits & Vegetables Nuts Ice cream (100 ml) 250 Dhokla (2 pcs) 100 Banana 116 Groundnut 567 Pastry (1 no.) 290 Green leafy veg 130 Apple 59 Cashew nut 596 (1 katori) Grapes, pale green 71 Coconut, fresh 444 Milk cake (1 piece) 300 Idli (2 nos. x 155 55 g each) Custard apple 104 Miscellaneous Butter (2 table spoon) 180 Dosa (2 nos. x 250 Jack fruit 88 Jaggery 383 45 g each) Raisins 308 Sugar 398 Fried Cashew (50 g) 375 Tinned cheese 105 Potato 97 Veg oils 900 (2 tbsp)these amino acids, provided the supply of nitrogen is adequate. oilseed cakesThese amino acids are known as nonessential amino acids. The major sources of proteins are depicted in Table - 3.Others cannot be synthesized by the body and must therefore Role in health and disease : The important functions ofbe supplied in diet. These are the eight essential amino acids proteins are summarized in the Box- 1.viz. leucine, isoleucine, lysine, valine, methionine, threonine,tryptophan and phenylalanine. To these may be added histidine Quality of Proteinswhich appears to be essential for the growth of infants (5, 6). The nutritive value of a protein depends upon its amino acidSources of proteins : There are two main dietary sources of composition. A biologically complete protein is one whichproteins : contains all the essential amino acids in adequate amounts to(a) Animal Sources : These include eggs, milk, meat and fish meet human requirements. Proteins from foodstuffs of animal origin, such as milk, meat and eggs are biologically superior(b) Vegetable Sources : Pulses, nuts, cereals, beans and to proteins of vegetable origin as animal proteins have all the Box - 1: Functions of Proteins (a) Proteins are important for body building, growth, repair and maintenance of body tissues (b) Proteins are required for the synthesis of plasma proteins, haemoglobin, enzymes and hormones (c) Proteins like collagen, actin and myosin form the structural tissues - skin and muscles (d) Proteins act as transport carriers for many molecules like iron, haemoglobin, lipids etc. (e) Antibodies are also proteins. Proteins are involved in the acute phase of inflammation as well (f) Albumin, a protein, acts as a buffer in the maintenance of blood pH (7) • 718 •
  10. 10. Recommended Dietary Allowance (RDA) for Proteins : Table 3 : Major sources including their protein content (g The requirement of proteins is generally accepted to be 1g/ per 100g) Kg/day for adults. So the recommended dietary allowance Protein for a reference adult male works out to 60g/day and for a Food Item Protein Food Item content reference adult female it is 50g/day. An additional allowance (Source) content (g) (Source) (g) of 15g/day is recommended for pregnancy. During lactation Eggs 13.3 Milk (Cow) 3.2 an extra allowance of 25g in the first 6 months and 18g in the subsequent 6 months is recommended. Children have a Meat (goat, lean) 21.4 Fish (Hilsa) 21.8 higher protein requirement as elaborated in Table - 4 (1). A Pulses (red gram) 22.3 Soya bean 43.2 detailed account of the requirements of proteins for pregnant Groundnuts 25.3 Wheat flour 12.1 and lactating women, infants and children is discussed in the chapter on “Physiological requirements of nutrients”. An Rice (raw, milled) 6.8 French Beans 1.7 attempt is also made to elaborate as to how this requirement could be met in the typical Indian conditions. Some tips on improving the consumption of proteins is given in the Box- 3.essential amino acids present in them. Most of the vegetableproteins lack one or more amino acid and are thus classified as Deficiency can occur when the diet does not provide enoughbiologically incomplete proteins. protein in relation to the requirement which may be high as in the case of young growing children. Secondly, if energy intakeThe essential amino acid that is in shortest supply in a given is insufficient proteins will be diverted to produce energy andfood item is known as the limiting amino acid, for example thus causing a deficiency of proteins. Childhood infectionsthe limiting amino acid in wheat is lysine and in pulses it is (esp. measles) also play an important role in triggering andmethionine. The quality of vegetable proteins in a vegetarian sustaining a long term protein deficiency. Protein Energydiet can be improved by providing a suitable combination of Malnutrition (PEM) is a major cause of concern for children invegetable proteins. A relative lack of a particular amino acid in our country. PEM is discussed in greater details in Chapter onone protein can be compensated by simultaneous consumption ‘Nutritional Deficiency Diseases’.of another protein, which contains that limiting amino acid.This is known as supplementary action. Thus a diet combining Table - 4 : Recommended Dietary Allowance (RDA) forwheat products such as bread (chapati) with pulses (dal) will Proteinscompensate for these deficiencies (of lysine and methionine)and provide all the essential amino acids. Other similar Body Requirement Group Activityexamples from Indian diet are Idli-Sambhar, Wada-Pav, Rice- weight g/dayDal, Khichri etc. Sedentary workQuantitatively the quality of a protein is worked out in terms Man Moderate work 60 60of biological value, digestibility co-efficient, net protein Heavy workutilization and protein efficiency ratio. The working formulaefor each of these parameters are shown in the Box- 2. The net Sedentary workprotein utilization (NPU) is the most commonly used parameter. Moderate work 50 50A protein with an NPU of more than 65 is considered as of Heavy workoptimum quality. Egg protein is considered to have an NPUof 100 and is considered as ideal or reference protein against Woman Pregnant woman 50 +15which other proteins are compared with. Lactation 0-6 months 50 +25 Box- 2 : Quality of Proteins 6-12 months +18 The quality of a protein depends upon its amino acid composition. A protein containing all amino acids is 0-6 months 5.4 2.05/ Kg Infants considered as ‘ideal’. Egg protein is taken as the reference 6-12 months 8.6 1.65/ Kg protein. 1-3 years 12.2 22 Nitrogen retained x 100 Biological value (BV) = Children 4-6 years 19.0 30 Nitrogen absorbed 7-9 years 26.9 41 Nitrogen absorbed x 100 Digestibility co-efficient = Boys 10-12 years 35.4 54 Nitrogen intake Girls 10-12 years 31.5 57 Retained Nitrogen x 100 Net Protein Utilization (NPU) = Boys 13·15 years 47.8 70 Intake of Nitrogen Girls 13·15 years 46.7 65 Weight gain in g Protein Efficiency Ratio (PER) = Boys 16-18 years 57.1 78 Protein intake in g Girls 16-18 years 49.9 63 • 719 •
  11. 11. Box - 3 : Recommendations on Diet for Proteins Table-5 : Major sources including their fat content Eat nutritionally balanced diet to get adequate protein (g/100g) Meat and fish are good sources Food Item (source) Fat content (g/100g) Vegetarians must eat proper combination of plant proteins Eggs (hen) 13.3 from both cereal and pulses groups Milk, cow 4.1 Include Soyabean in your diet Meat (Goat lean) 3.6 Two to three servings of protein-rich food must be ensured Fish (Hilsa) 19.4 every day Ghee 100 One serving may be equivalent to : Butter 81.0 - One to two cups of cooked meat, poultry, fish Groundnut 40.1 - Half cup of cooked dry beans/ lentils/ legumes Mustard seeds 39.7 - One egg Coconut, fresh 41.6 - Handful of fried/roasted- salted groundnuts Sunflower seeds 52.1 - Handful of roasted Bengal grams than 80 g / day.Fats Some amount of fat is present in all food stuffs. From theFats are organic compounds, which are insoluble in polar nutritional standpoint, important of them are cereals, pulses,solvents (water) but soluble in organic solvents such as ether, oilseeds, nuts, milk, eggs and meat. Contrary to generalchloroform and benzene. These are actual or potential esters awareness, this invisible fat contributes substantially to theof fatty acids. Fats are only distinguished from oils by their total fat consumption and essential fatty acid intake of our diet.different melting points; fats are solid and oils liquid at room Cereals and pulses which are otherwise perceived to be poor intemperature. ‘Fats’ and ‘oils’ are the ones which the housewife fats contribute significantly towards fat intake of a Indian diet.buys and ‘lipid’ (Greek, lipos meaning fat) is the term used by This is because most Indians depend on the ‘staple’ of cereals,biochemists. However, the general term fat is commonly used consumed in a large quantity. The invisible fats may accountto refer to the whole group and is used interchangeably with for 20 to 50% of all fats consumed, depending on the type oflipids. diet. It should however contribute to not less than 6% of totalSources of fats : Dietary fats are derived from two main energy or about 15g of invisible fats per day.sources: Types of Fatty Acids(a) Animal Sources : They are milk and milk products (ghee,butter), lard, egg and fish oils. Animal fats in general are poor Fatty acids are composed of a straight hydrocarbon chain withsources of essential fatty acids with the exception of certain one methyl group (—CH3) and terminating with a carboxylicmarine fish oils such as cod liver oil and sardine oil, but they acid group (—COOH). Hydrogen atoms are attached to theare good sources of retinol and cholecalciferol. carbon chain; the number of hydrogen atoms determines the degree of saturation (with hydrogen atoms) of the fatty acid.(b) Vegetable Sources : They include various edible oils such as A fatty acid with hydrogen atoms on every arm is said to begroundnut, gingely, mustard, cottonseed, safflower, rapeseed, ‘saturated’. Unsaturated fatty acids contain double carbonpalm and coconut oil. Vegetable oils with the exception of bonds where there is no hydrogen. If there is only one doublecoconut oil are all rich sources of essential fatty acids, but they bond, the fatty acid is termed as monounsaturated and whenlack retinol and cholecalciferol except red palm oil which is rich more than one double bond is present, the fatty acid will bein carotenoids. Major sources including their fat content are polyunsaturated.given in Table - 5. Saturated Fatty Acids (SFA) : Saturate (Latin, to fill, in thisVisible and invisible fats : The visible fats are generally case with hydrogen). Saturated Fatty acids have a relatively highderived from animal fats e.g. butter or ghee or from plant melting point and tend to be solid at room temperature. These(vegetable) oils like groundnut, mustard, coconut, sunflower or are obtained from animal storage fats and their products e.g.safflower seeds. Hydrogenated oils and margarine would also meat fat, lard, milk, butter, cheese and cream. Fats from plantbe classified as visible oils. The visible fat is added to food for origin tend to be unsaturated with the exception of coconutcooking, flavouring or shortening. These are the major sources oil and palm oil. A high intake of SFA is associated with anof fats in our diet. Chemically they are triglycerides of fatty increase in LDL and total cholesterol and thus increases the riskacids and could be saturated or unsaturated. It is now believed of atherogenesis and cardiovascular disease. Some examples ofthat the bare minimal requirement of visible fats to meet the SFAs are Myristic acid, Palmitic acid and Stearic acid.essential fatty acid requirements is 15 to 25 g per day. Theupper limit is fixed at 30% of the total energy intake or less Monounsaturated Fatty Acids (MUFA) : MUFA contain only one double bond and are usually liquid (oil) at room temperature. Olive oil and rapeseed oil are good dietary sources • 720 •
  12. 12. of MUFA. MUFA are also present in meat fat and lard. Dietary Trans Fatty Acids (t-FA)MUFA does not raise plasma cholesterol. They lower LDL Trans fatty acids rarely occur in nature. These are producedcholesterol without affecting the HDL. Oleic acid is an example during the partial hydrogenation of PUFA. In Indian homes thisof MUFA. process takes place commonly when oil is heated over and overPolyunsaturated Fatty Acids (PUFA) : PUFA contain two or again as it happens during the process of frying puri, pakori ormore double bonds and they too are liquid at room temperature. samosa, esp. when the same oil is boiled repeatedly. Trans fattyThey are easily oxidized in food and in the body. PUFA have a acids have been associated with adverse effects on lipoproteinvital role in immune response, blood clotting and inflammation. status by elevating LDL and depressing HDL.PUFA are divided into omega-3 (ω3) or omega 6 (ω6) groups Essential Fatty Acids (EFA)of PUFA. Omega-3 (ω) polyunsaturated fatty acids PUFA arefound in fish and fish oils. The health benefits of these include If fats are entirely excluded from the diet, retarded growth,reducing the cardiovascular risk factors (see Box - 4). Research dermatitis, kidney lesions and an early death might result.also indicates their beneficial role in cognitive function of brain. Studies have shown that feeding of certain unsaturated fattySome common omega-3 fatty acids are α-linolenic acid (linseed, acids e.g. linoleic and linolenic acid is effective in curing thesoyabean, rapeseed, leafy vegetables), eicosepentaenoic acid condition. It is therefore evident that certain unsaturated fatty(marine algae, fish oils) and docosahexenoic acid (fish oils). acids cannot be synthesized in the body and must be acquired from diet. These are essential fatty acids. EFA are commonly Box-4 : Omega-3 (ω3) Fatty Acids in Prevention and found in plant and fish oils (8). The EFA requirement is 3-6% of Therapy the total energy intake depending on the age and physiological status of the individual. Fatty acid content of different fats is Coronary artery Disease (CAD) : Omega-3 (ω3) Fatty Acids given in Table - 6. reduce the tendency of platelet aggregation, blot clot Why fats in diet? : If the contemporary literature is to be formation and thus atherosclerosis. Chances of cardiac believed, one tends to agree that fats are well known for their arrhythmias also go down, thus benefiting in CAD. role in causation of many chronic diseases rather than any Hypertension : They lower the high blood pressure in worthwhile virtue! Then why should fat be consumed at all hypertensives. and how much? The main functions of fat are elaborated in the Box - 5. Hyperlipidaemia : They lower the high blood lipids (triglycerides and total cholesterol), while increasing HDL-c. Unlike proteins where the precise intake, assimilation, excretion and thus requirement can be worked out, the quantity of fats Bronchial asthma : ω3 Fatty Acids reduce inflammation, that should be included in a well balanced diet is a matter of frequency and severity of asthma. conjecture. The following aspects however are important in Diabetes : They lower the high blood triglycerides blood considering the recommendation for fat intake : pressure and reduce leakage of proteins from small vessels, a) The quantity of fat intake should be good enough so that thus improving the overall metabolism and the diabetic requirement of essential fatty acids (which are a component state. of fats) is met. b) Absorption of fat soluble vitamins should not be Autoimmune disorders : Omega 3-Fatty Acids are known to compromised. reduce pain, inflammation and joint stiffness in rheumatoid c) Fat intake should be sufficient enough to make diet arthritis. Other autoimmune disorders also improve with palatable. their supplementation. d) Some stores must be maintained in the body to tide over a Miscellaneous : They are found to be useful in conditions like lean period. migraine, inflammatory skin disorders and osteoarthritis. e) It should not be so much in quantity that it causes undesirable effects on health. Cholesterol Cholesterol is always talked as if it is the hazardous abnormal fat. It is considered by many as a type of a saturated fat. In fact it is only a fat related compound. Chemically it falls under the group of sterols. It is named after the body material where it was first identified, the gallstones (Greek, chole, bile; steros, solid) Synthesis : It is synthesized only in the animal body. All plant products are free of cholesterol. The human body synthesizes indigenous cholesterol primarily in liver (but also in adrenal cortex, skin, intestines, testis and ovaries), for sustaining life. It is a normal constituent of bile and a principal part of the gall stones Sources : The important dietary sources are egg yolk, meat (liver and kidney). There are no plant sources of cholesterol RDA : Since it is synthesized indigenously in the body, there is no dietary requirement of cholesterol. However, the upper limit of cholesterol consumption has been put at 300mg per day Functions : It is vital as a precursor to various steroid hormones e.g. sex hormones and adrenal corticoid hormones. Hazards : In dysfunctional lipid metabolism, it is considered the major factor for atherosclerosis. Epidemiological studies have linked high cholesterol intake to the increased risk of coronary heart disease • 721 •
  13. 13. Table - 6 : Approximate fatty acid composition of common Table - 7 : RDA of Fats for Indians fats and oils (g/100g) (8) Group Particulars Body wt (Kg) RDA Fat (g/d) Oil/Fat Satu- MUFA Lino- α-lino- Predomi- Sedentary work rated leic lenic nant FA acid acid Man Moderate work 60 20 Coconut 90 7 2 <0.5 SFA Heavy work Palm kernel 82 15 2 <0.5 SFA Sedentary work Ghee 65 32 2 < 1.0 SFA Moderate work 50 20 Vanaspati 24 19 3 <0.5 SFA (t-FA) Heavy work Red palm oil SFA + Woman Pregnant woman 50 40 9 <0.5 50 30 MUFA Lactation Palm oil SFA + 45 44 10 <0.5 0-6 months MUFA 50 45 Olive 13 76 10 <0.5 MUFA 6-12 months Groundnut 24 50 25 <0.5 MUFA 0-6 months 5.4 Infants Rape/ MUFA 6-12 months 8.6 8 70 12 10 Mustard 1-3 years 12.2 Sesame MUFA + Children 4-6 years 19.0 25 15 42 42 1.0 PUFA 7-9 years 26.9 Rice bran MUFA + 22 41 35 1.5 Boys 10-12 years 35.4 PUFA 22 Cotton seed 22 25 52 1.0 PUFA Girls 10-12 years 31.5 Corn 12 32 55 1.0 PUFA Boys 13·15 years 47.8 22 Sunflower 13 27 60 <0.5 PUFA Girls 13·15 years 46.7 Safflower 13 17 70 <0.5 PUFA Boys 16-18 years 57.1 22 Soyabean 15 27 53 5.0 PUFA Girls 16-18 years 49.9Based on these aspects, the ICMR has recommended levels of Quantity of Fat : With an improving economy and a richerfat intake for Indians (RDA) that are summarised in Table - 7. lifestyle we tend to consume a higher calories especially from the fat source. Higher calories lead to obesity and many otherRecommended Dietary Allowance : The RDA for adults is 20g lifestyle diseases. A high level of fat in diet is notorious inof visible fat per day. For pregnant and lactating women it is 30 the causation of atherosclerosis and so is a major risk factorand 45 g respectively. The RDAs for various groups are given in for Cardiovascular Diseases (CVD) including coronary arteryTable - 7 (1). Fat content of diet should not exceed 20 to 30% of disease and strokes. Any amount that contributes to more thanthe total calories consumed. The dietary cholesterol should be 30% of total calorie intake is considered as high. Low physicallimited to 300 mg/day. activity and sedentary lifestyle further augment the risk.Hazards of Excess Fat in Diet : Excess fat is dangerous on Quality of Fat : High levels of saturated fatty acids are moretwo accounts. First, in case it is consumed in a higher quantity dangerous. A proportionately higher content of polyunsaturatedand secondly if the wrong quality of fat is consumed. Box - 5 : Functions of Fats They are concentrated sources of energy providing about 37.7 KJ/g or 9 Kcal /g. Fats serve as vehicle for fat soluble vitamins (A.D, E and K). Fats are structural components of cell and cell membrane. They are the sources of essential fatty acids. Linoleic acid and arachidonic acid are precursors of prostaglandins which are required for a wide variety of metabolic functions. Apart from their nutritional significance, fats improve the palatability of diet, delay gastric emptying & raise the caloric density. Some fats can be converted to biologically active compounds such as steroid hormones, interleukins, thromboxanes and prostaglandins and bile acids (from cholesterol). • 722 •
  14. 14. fatty acids is found to be protective for CVD. Unfavourable Table - 8 : Major sources of carbohydrates (per 100 g) (1)levels of certain lipoproteins have adverse effects on health.High levels of LDL are associated with higher atherosclerotic Carbo- Carbo-risk so LDL is colloquially known as ‘bad cholesterol’. A high Food stuff hydrates Food stuff hydrateslevel of HDL has favourable effect on the cardiovascular system (g) (g)and is termed as ‘good cholesterol’. Cereals & Millets Pulses & Legumes Wheat flour 69.4 Bengal gram 60.9 Tips on fat intake Rice polished 78.2 Soya bean 20.9 Use minimal oil for preparation Bajra 67.5 Rajmah 60.6 Food preparation Rotate the types of oil used Maize dry 66.2 Redgram (Arhar) 57.6 Use only lean cuts of meat Prefer fish to poultry Ragi 72.0 Pea dry 56.5 Meat Prefer poultry to mutton/beef/pork Fruits & Vegetables Miscellaneous Limit added oils in meat preparations Banana 27.2 Milk, cow 4.4 Avoid more than one egg a day Apple 13.4 Groundnut 26.1 Eggs Avoid adding oil to egg preparations Mango 16.9 Cashew nut 22.3 Use egg whites freely Raisins 74.6 Coconut, fresh 13 Milk Prefer low fat milk Tapioca 38.1 Jaggery 95 Sweet potato 28.2 Sugar 99.4Carbohydrates Potato 22.6 Honey 79.5Carbohydrates are the basic source of fuel to run life on earth.It is these carbohydrates into which the energy from sun is fructose. Lactose is found in milk. It is hydrolysed to glucoseconverted through the process of photosynthesis by plants. and galactose. Maltose is present in malted wheat and barley.In fact this is the energy that is used by all living organisms. Other sources are nuts and seeds.Thus carbohydrates can be considered as the very ‘basis’ of Functions of Carbohydrates : Carbohydrates are the mostlife. Chemically carbohydrates are polyhydroxy aldehydes or significant and cheapest source of energy in the diet. Oneketones, or substances that produce such compounds when gram of carbohydrates provides 4 Kcal energy. Carbohydrateshydrolyzed. They contain carbon, oxygen and hydrogen in provide 60 to 85% of energy in our Indian diet. Various kindsproportion approximating that of a ‘hydrate of carbon’ (CH2O), of sugars (glucose, fructose, sucrose etc.), most literally,hence the term carbohydrate. impart the sweet taste to life! Carbohydrates play an importantClassification : From the nutritional or functional point of role wherein glycogen resources in the muscles and liver areview, carbohydrates can be divided into two categories. in a state of dynamic exchange with the energy balance (of(a) Available carbohydrates : These are the carbohydrates intake and expenditure) through the liver. A constant supplywhich can be digested in the upper gastrointestinal tract, of carbohydrates has a protein sparing action and proteinsabsorbed and utilized. These are further sub-classified as are not required to be broken down for energy. Similarly fatspolysaccharides, disaccharides, monosaccharides. are also spared to be used up if enough carbohydrate supply(i) Polysaccharides such as starch, dextrin and glycogen is maintained. The brain exclusively uses glucose and is(ii) Disaccharides such as lactose, sucrose and maltose dependent on its constant supply for its functioning.(iii) Monosaccharides such as glucose, fructose and galactose. Fibre, which is a type of carbohydrate, has the important(b) Dietary Fibre : The second category comprises of function of increasing faecal bulk, stimulating peristalsis andunavailable carbohydrates or dietary fibre, which are difficult blocking cholesterol synthesis in the liver.to digest. These are cellulose, hemicellulose, gums, pectins etc. Requirement of Carbohydrates : In a prudent dietA detailed account of these is given later in this chapter. carbohydrates should contribute to 60 to 70% of total energySources of Carbohydrates : The major source of dietary (1). This translates to about 360 to 400g carbohydrates for acarbohydrates in an Indian set up is starch from cereal grains, 2400 Kcal diet. Details about role and requirements of dietarymillets, legumes, roots and tubers (Table - 8). fibre are discussed in forthcoming paragraphs.With increasing prosperity as in industrial societies, sugar Problems Due to Deficiency and Excess : Whenever therehas replaced complex carbohydrates as the main source. is a deficiency of carbohydrates in diet not compensated byThe presence of monosaccharides (free glucose or fructose) other nutrients, a situation of energy deficiency sets in. This isis limited to fruits and vegetables, otherwise they are not typically seen in infants and children wherein protein calorieabundant in natural foods. Fructose is found in honey, fruits malnutrition is not uncommon. A similar situation of energyand vegetables. Sucrose and Lactose are the commonest deficiency may result in food deprived people in cases ofdisaccharides. Sucrose is extracted from sugar cane. Table starvation as encountered in famines and droughts. Anorexiasugar is 99% sucrose. Sucrose gets hydrolysed into glucose and nervosa is a condition with a major psychological component, • 723 •
  15. 15. wherein the patient doesn’t eat food and ends up being cachexic. On the other hand the natural gel forming fibres like pectins,A very low carbohydrate diet results in utilization of other gums and mucilages are soluble.macronutrients (lipids and proteins) for energy and result in Sources and Losses : Cereals, fruits and vegetables are theproduction of ketone bodies (ketosis). Eventually bone mineral chief sources of fibres. The important sources of soluble andloss, hypercholesterolaemia and increased risk of urolithiasis insoluble fibre are summarised in Table - 9.may result.Consumption of an excess of carbohydrates seems to be a bigger Table - 9 : Major food sources of fibreproblem in the present day scenario of progressive economies. Insoluble fibresIf the intake is large enough to provide excessive calories suchan individual ends up being obese and might fall prey to a Vegetables : Peas, beans, amaranth leaveshost of lifestyle diseases (discussed in another chapter). It is Cereals : Rye, bran flakes, brown rice, Corn, whole wheatinteresting to note that excess of even few calories per day(100-200 Kcal) over a couple of months accumulates enough Whole meal cereals : Dalia, whole meal flour, Ragicalories to cause obesity. porridgeDietary Fibre Breads : Granary bread, brown breadDenis Burkitt (a surgeon) and Hugh Trowell (a physician), Legumes : Bengal gram (whole), Lentils pulses and dalsserved for 30 years, after the World War II, in Makareree Sprouts : Sprouted grains, legumesUniversity, Kampala, Uganda, before returning to Britain. Theywere struck by the great difference in the pattern and nature Fruits : Fruits with edible seedsof disease affecting the affluent West as opposed to more Soluble fibreprimitive communities. They concluded that the large amount Citrus fruits : Orange, limeof dietary fibre was not only responsible for the faecal bulk butwas also directly or indirectly related to the difference in the Berries : Straw berry, rasp berrypattern of disease. A ‘fibre hypothesis’ was thus formulated Other Fruits : Pomegranate, Figs, grapes, guava, Sapota,which suggested that unrefined complex carbohydrates Custard appleprotected against the ‘western ailments’ : colonic cancer,diverticular disease, appendicitis, constipation, hemorrhoids, Functions : Dietary fibre stimulates chewing, improves flowhiatus hernia, varicose veins, diabetes, heart disease, gall of gastric juice and provides a sense of satiety. Insoluble fibrestones, obesity etc. binds to water in the colon and swells. Hence, it forms substrateDietary fibres are the remnants of the plant cell resistant for colonic bacterial fermentation. This stimulates peristalsisto hydrolysis by alimentary enzymes and do not provide which increases transit time in the colon thereby reducing thesignificant nourishment. They remain in the ileum but are risk of constipation and possibly that of colon cancer. Somepartially hydrolyzed by the colonic bacteria. The term ‘dietary fibres like lignin helps in prevention of absorption of bile acidsfibre’ is a broad term which includes Non Starch Polysaccharide by binding to them. On the other hand soluble fibres prevent(NSP) and related material such as resistant starch, resistant the micelle formation by binding with bile acids &and otheroligosaccharides, lignin and complex assemblies of plant tissue lipids (11).where polysaccharides occur in close association with other Recommended Dietary Allowance : The diet should containmolecules (9). 35-40 grams of dietary fibre per day (15g per 100Kcal) (1).Classification : Fibres can be Carbohydrate fibres and non- Fibre content of selected food stuffs are given in Table - 10.carbohydrate fibres. The carbohydrate fibres include NonStarch Polysaccharides (NSP) which arenormally present in cell wall, cement, plant Table - 10 : Dietary fibre content of common foods (g/100g)gums, mucilages and algal polysaccharides; Fibre content Fibre content Foodstuff Foodstuffand the Resistant Oligosaccharides (ROS) (g per 100g) (g per 100g)which are found in leguminous seeds e.g. Cereals & Legumes FruitsRajma, soy beans and gram (10). The NonCarbohydrate fibres include Lignin which is Rice, raw, milled 0.2 Guava 5.2a large compound forming the woody part Wheat flour, whole 1.9 Mango, papaya 0.7of some plants. It strengthens the plant cell Bengal gram, whole 3.9 Pomegranate 5.1walls.Fibre can also be classified according to Red gram (Dal arhar) 1.5 Peach, pears, apple 1.0-1.2solubility in water, as soluble or insoluble. Peas dry, Rajmah 4.5 Figs, Sapota 2.2-2.6Insoluble fibre consists mainly of cellulose, Green vegetables Nutshemicellulose and lignin. Since they remainundigested in the gut they form bulk and help Cabbage, cauliflower, Areca nut 1.0 -1.2 11.2in movement of the food and peristalsis. Thus Fenugreek (maithi)they help in elimination of waste products as Amaranth 1 to 6.1 Coconut fresh 3.6well. After absorption of water the fibre swellsup and facilitates the gut movement further. Spinach, radish leaves 0.6 Groundnut 3.1 • 724 •

×