UNIT-2 Notes.pdf

UNIT-2 RECOMMENDED DIETARY ALLOWANCE AND FOOD HABITS Recommended dietary allowance – Refers to the daily dietary nutrient intake level sufficient to meet the nutrient requirements of nearly all (97-98 percent) healthy individuals in a particular life stage and gender group. For all t...

UNIT-2 RECOMMENDED DIETARY ALLOWANCE AND FOOD HABITS Recommended dietary allowance – Refers to the daily dietary nutrient intake level sufficient to meet the nutrient requirements of nearly all (97-98 percent) healthy individuals in a particular life stage and gender group. For all the nutrients (except energy) estimates of allowances are arrived at by determining the average. Taking the mean requirement of nutrients and adding to it twice the standard deviation of the mean. Requirement = Mean ± 2SD The value will meet more than 97.5% of the population which is composed of individuals with a satisfactory normal distribution of requirements The term is used to evaluate individual diets primarily. The RDA is inappropriate for dietary assessment of groups as the intake level exceeds the requirement of a large proportion of individuals within the group. History of RDA - the effects of deficient diets were so revealing that in 1936 the League of Nations set up an Expert Committee to recommend daily dietary allowances for each of the known nutrients. The first edition of the Recommended Dietary Allowances (RDAs) was published in 1943 during World War II with the objective of “providing standards to serve as a goal for good nutrition.” It defined, in “accordance with newer information, the recommended daily allowances for the various dietary essentials for people of different ages”. Our Indian recommendations were revised in 1958, 1968, 1978, 1988 (Published in 1989), 2010, and 2020. Because of incorporating newer research findings on human nutrient requirements, the existing Indian RDAs were updated, revised, and published in the year 2023 by the Indian Council of Medical Research. Purpose of RDA – 1. For planning and procuring food supplies for population subgroups 2. For interpreting food consumption records of individuals and populations 3. For establishing standards for food assistance programs 4. For evaluating the adequacy of food supplies in meeting national nutritional needs 5. For designing nutrition education programs 6. For developing new products in the industry 7. For establishing guidelines for nutrition labeling of foods. 8. planning food needs of catering organizations The important points regarding the RDA for Indians are as follows: 1. The dietary allowances suggested for adults are for a reference man weighing 60 kg and for reference woman weighing 55 kg. The allowances for calories and proteins and for B-complex vitamins should be increased or decreased depending on the body's weight. The profiles of a reference man and a reference woman are as follows: Reference Indian Adult Man and Woman The Indian Reference Man is between 18-29 years of age and weighs 60 kg with a height of 1.73m, a BMI of 20.3 and is free from disease and physically fit for active work; on each working day, he is engaged in 8 hours of occupation which usually involves moderate activity, while when not at work, he spends 8 hours in bed, 4-6 hours in sitting and moving about, 2 hours in walking and in active recreation or household duties. The Indian Reference Woman is between 18-29 years of age, Non-Pregnant Non-Lactating (NPNL) and weighs 55 kg with a height of 1.61m and a BMI of 21.2, is free from disease and physically fit for active work; on each working day she is engaged in 8 hours of occupation which usually involves moderate activity, while when not at work, she spends 8 hours in bed, 4-6 hours in sitting and moving about, 2 hours in walking and in active recreation or household duties 2. The protein allowance recommended is about 1 gram per kilogram body weight per day. Since Indians are predominantly vegetarians, this protein is assumed to be derived from a mixture of vegetable foods. Proteins of animal origin have superior biological value as compared to vegetable proteins. However, a mixture of vegetable proteins improves the biological value. For infants and children as well as for pregnant and nursing women, it is desirable to supply about 25 percent of the total protein requirement from animal foods such as milk, meat, eggs, fish, etc. 3. The intake of fat should be limited to not more than 15 percent of the calories in the diet. Of these, at least 15 g of vegetable oils should be included in the diet to meet the requirements of the essential fatty acids. It is now recommended that the human diet contain about 4 percent of calories as linoleic acid and linolenic acid. 4. About 60-65 percent of the total calorie requirement may be met through intake of carbohydrates.  5. Allowance of phosphorus is not mentioned since most dietary ingredients are rich in phosphorus. 6. A normal well-balanced diet generally meets the requirements for trace elements like Mg, Cu, and I. Hence, no RDA for these is mentioned. 7. Vitamin A is found either as retinol or ẞ carotene in the diet. The former is preformed vitamin A while the latter is the precursor of vitamin A. Both yield vitamin A. One mg ẞ carotene is equivalent to 0.25 mg retinol. Total vitamin A value of the diet as retinol (ug) ẞ retinol (ug) = ẞ carotene/4. I 8. Vitamin D is formed in the body by conversion of its precursor by the action of sunlight. Partial requirement of vitamin D may be met by this conversion but it cannot be always relied upon especially in case of children. So, RDA for vitamin D is given. 9. The requirement for thiamine, riboflavin and niacin are related to the calorie intake of the person. The RDA of each of these per 1000 calories are: Thiamine-0.5 mg Riboflavin-0.55 mg Niacin-6.6 mg The RDA for niacin includes the contribution of dietary tryptophan. 60 mg tryptophan is equivalent to 1 mg niacin. Thus, RDA are the levels of intake of essential nutrients considered to be adequate to meet the known nutritional needs of all healthy persons according to the judgement of the Nutrition Expert Group of the ICMR on Dietary Allowances. RDA prescribed for adults depends on the activity level of an individual 1. Sedentary workers- Sitting job, do work using brain and hands. 2. Moderate workers- Work energetically for a few hours using many parts of the body like hands, feet, and muscles. 3. Heavy workers- Use different parts of the body for several hours Nutrient Requirement- The requirement for a particular nutrient is the minimum amount that needs to be consumed to prevent symptoms of deficiency and to maintain a satisfactory level of the nutrient in the body. For example in the case of infants and children, the requirement may be equated with the amount that will maintain a satisfactory rate of growth and development. Similarly for an adult, the nutrient requirement is the amount that will maintain body weight and prevent the depletion of the nutrient from the body which otherwise may lead to deficiency. In physiological condition like pregnancy and lactation, adult women may need additional nutrients to meet the demand of fetal growth along with their own nutrient needs. Now within each group (say infants or adults etc) there may be individual variations in the nutrient requirements. For instance, there may be a period of low intake or the quality of the diet may vary, similarly, the effect of cooking and processing may be different and the bioavailability of the nutrient from the diet may also vary. A safety factor is added over and above the nutrient requirement for each group to arrive at the Recommended Dietary Allowances. REQUIREMENT + SAFETY MARGIN = RECOMMENDED DIETARY INTAKE The nutritional requirements are affected by several factors such as the following: Age (infant, adolescent, aged). Infants require more protein per kilogram of body weight than adolescents since their metabolic rate is much faster than that of adolescents. Sex (male or female) Adolescent girls require more iron than adolescent boys in order to replace the iron lost during menstruation every month. Body size (height, weight, surface area, stature). A tall heavily built man needs more calories than a small- statured man since his body surface area is more than that of the latter. Physiological state (pregnancy, lactation). A pregnant woman requires more nutritious food than an ordinary adult woman since she has to meet the additional nutritional requirements of the growing foetus. Type of work (sedentary, moderate, heavy). A sedentary worker requires less calories than a heavy worker since the former expends less energy than the latter during work DIETARY GUIDELINES FOR INDIANS ACCORDING TO ICMR (Report: May 2024) Guideline 1: eat a variety of foods to ensure a balanced diet. Guideline 2: ensure provision of extra food and health care during pregnancy and lactation. Guideline 3: ensure exclusive breastfeeding for the first six months and continue breastfeeding till two years and beyond. Guideline 4: start feeding homemade semi-solid complementary foods to the infant soon after six months of age. Guideline 5: ensure adequate and appropriate diets for children and adolescents both in health and sickness. Guideline 6: eat plenty of vegetables and legumes. Guideline 7: use oils/fats in moderation; choose a variety of oil seeds, nuts, nutricereals and legumes to meet daily needs of fats and essential fatty acids (EFA). Guideline 8: obtain good quality proteins and essential amino acids (EAA) through appropriate combination of foods and avoid protein supplements to build muscle mass. Guideline 9: adopt a healthy lifestyle to prevent abdominal obesity, overweight and overall obesity. Guideline 10: be physically active and exercise regularly to maintain good health. Guideline 11: restrict salt intake. Guideline 12: consumes safe and clean foods. Guideline 13: adopt appropriate pre-cooking and cooking methods. Guideline 14: drink an adequate quantity of water. Guideline 15: minimize the consumption of high fat, sugar, salt (HFSS), and ultra-processed foods (UPFs) Guideline 16: include nutrient-rich foods in the diet for the elderly for health and wellness. Guideline 17: read the information on food labels to make informed and healthy food choices. Food Habits- Food habits can also be referred to as eating habits. Eating habits refer to why and how people eat, which foods they eat, and with whom they eat, as well as the ways people obtain, store, use, and discard food. Individual, social, cultural, religious, economic, environmental, and political factors all influence people's eating habits. Major factors influencing food habits/ eating habits The main reason we eat is because of hunger, but our food choices are not solely based on our physiological or nutritional needs. Factors influencing food choices can vary based on different life stages and vary from person to person or group to group. Therefore, one single intervention to change food choice behavior will not be effective for all population groups. Some of the other factors that influence food choice include: 1.1 Biological factor of food habit Hunger and satiety Our physiological needs provide the basic determinants of food choice. Humans need energy and nutrients to survive and will respond to feelings of hunger and satiety (satisfaction of appetite, state of no hunger between two eating occasions). The central nervous system is involved in controlling the balance between hunger, appetite stimulation, and food intake. The macro-nutrients i.e. carbohydrates, proteins, and fats generate satiety signals of varying strength. The balance of evidence suggests that fat has the lowest satiating power, carbohydrates have an intermediate effect and protein is the most satiating49. The energy density of diets has been shown to exert potent effects on satiety; low energy density diets generate greater satiety than high energy density diets. The high energy density of high-fat and/or high-sugar foods can also lead to ‘passive overconsumption’, where excess energy is ingested unintentionally and without the consumption of additional bulk. An important satiety signal may be the volume of food or portion size consumed. Many people are unaware of what constitutes appropriate portion sizes and thus inadvertently consume excess energy. Palatability and Sensory aspects Palatability is proportional to the pleasure someone experiences when eating a particular food. It is dependent on the sensory properties of the food such as taste, smell, texture and appearance. Sweet and high-fat foods have an undeniable sensory appeal. It is not surprising then that food is not solely regarded as a source of nourishment but is often consumed for the pleasure value it imparts. Here is an increase in food intake as palatability increases. The senses play a significant role in shaping our food choices. It encompasses all sensory experiences that occur when we eat, including taste, smell, appearance, and texture. These sensory aspects greatly influence behavior towards food. For example, humans are typically born with a preference for sweetness and a dislike for bitterness. However, individual taste preferences and aversions evolve based on personal experiences, attitudes, beliefs, and expectations. 1.2 Economic and Educational factor of Food Choice Cost and accessibility The cost of food is a primary determinant of food choice. Whether the cost is prohibitive depends fundamentally on a person's income and socio-economic status. Low-income groups have a greater tendency to consume unbalanced diets. However, access to more money does not automatically equate to a better quality diet but the range of foods that one can choose should increase. Accessibility is another important factor influencing food choice, which is dependent on resources such as transport and geographical location. Healthy food tends to be more expensive when available within towns and cities compared to supermarkets on the outskirts. However, improving access alone does not increase the purchase of additional fruits and vegetables, which are still regarded as prohibitively expensive. Education and Knowledge Studies indicate that the level of education can influence dietary behavior during adulthood. In contrast, nutrition knowledge and good dietary habits are not strongly correlated. This is because knowledge about health does not lead to direct action when individuals are unsure how to apply their knowledge. Furthermore, the information circulated on nutrition comes from a variety of sources that are viewed as contradictory or mistrusted, which discourages motivation to change. Thus, it is important to convey accurate and consistent messages through various media, on food packages, and of course via health professionals. 1.3 Social factors of food habit Cultural influences Cultural influences lead to differences in the habitual consumption of certain foods and in traditions of preparation, and in certain cases can lead to restrictions such as the exclusion of meat and milk from the diet. Cultural influences are however amenable to change: when moving to a new country individuals often adopt particular food habits of the local culture. Social Influence Social influences on food intake refer to the impact that one or more persons have on the eating behaviour of others, either direct (buying food) or indirect (learn from peer's behaviour), either conscious (transfer of beliefs) or subconscious. Even when eating alone, food choice is influenced by social factors because attitudes and habits develop through the interaction with others. Population studies show there are clear differences in social classes with regard to food and nutrient intakes. Poor diets can result in under- (micronutrients deficiency) and over-nutrition (energy over consumption resulting in overweight and obesity); problems that face different sectors of society, requiring different levels of expertise and methods of intervention. Social support can have a beneficial effect on food choices and healthful dietary change. For example, social support has been found to be a strong predictor for fruit and vegetable consumption among adults. Social support may enhance health promotion through fostering a sense of group belonging and helping people to be more competent and self-efficacious. 1.4 Meal patterns People have many different eating occasions daily, the motivations for which will differ from one occasion to the next. Most studies investigate the factors that influence habitual food choice but it may be useful to investigate what influences food choice at different eating occasions. The effects of snacking on health have been debated widely. Evidence shows that snacking can have effects on energy and nutrient intakes but not necessarily on body mass index. However, individuals with normal weight or overweight may differ in their coping strategies when snack foods are freely available and also in their compensatory mechanisms at subsequent meals. Moreover, snack composition may be an important aspect in the ability of individuals to adjust intake to meet energy needs. Helping young adults to choose healthy snack choices poses a challenge to many health professionals. In the home, rather than forbidding unhealthy snacks, a more positive approach may be the introduction of healthy snack options over time. Moreover, healthy food choices outside the home also need to be made more readily available. 1.5 Psychological factors 1. Stress/ Mood Psychological stress in modern life can change behaviors that affect health, like physical activity, smoking, or food choices. Stress can influence food intake differently for each person. Some eat more, while others eat less than normal when stressed. Stress-induced changes in eating and food choices can be caused by motivational, physiological, and practical factors. Prolonged work stress may lead to adverse dietary changes, weight gain, and increased cardiovascular risk. Today, we recognize that food influences our mood, and mood influences our choice of food. Attitudes towards food and concerns about weight gain can affect our relationship with food. Food cravings, particularly in women, can be influenced by mood and stress and may vary during the premenstrual phase. Depressed mood appears to influence the severity of these cravings. Thus, mood and stress can influence food choice behaviour and possibly short and long term responses to dietary intervention. 2. Eating disorders Eating behavior, unlike many other biological functions, is often subject to sophisticated cognitive control. One of the most widely practiced forms of cognitive control over food intake is dieting. Many individuals express a desire to lose weight or improve their body shape and thus engage in approaches to achieve their ideal body mass index. However, problems can arise when dieting and/or exercise are taken to extremes. The etiology of eating disorders is usually a combination of factors including biological, psychological, familial, and socio-cultural. The occurrence of eating disorders is often associated with a distorted self-image, low self-esteem, non-specific anxiety, obsession, stress, and unhappiness. Treatment of an eating disorder generally requires weight stabilization and one-to-one psychotherapy. Prevention is more difficult to define, but suggestions include avoidance of child abuse, avoidance of magnifying diet and health issues, showing affection without over-controlling, not setting impossible standards, rewarding small attainments in the present, and encouraging independence and sociability. 3. Consumer attitudes and beliefs Consumer attitudes and beliefs play a significant role in influencing food habits and intake. The way consumers view various food products, their beliefs about nutritional value, and quality, and their attitudes towards different food categories can have a substantial impact on their dietary choices. For instance, individuals who prioritize health and wellness may be more inclined to choose nutritious, organic options, while those with convenience in mind might opt for quick, prepared meals. Additionally, cultural, social, and environmental beliefs can also shape food habits and intake. Overall, understanding consumer attitudes and beliefs is essential for food producers and marketers to cater to the diverse preferences and needs of consumers, while also promoting healthier and more sustainable food choices. 1.6 Time limitations Many people, especially younger and well-educated individuals, often cite lack of time as a reason for not following nutritional advice. Those who live alone or cook for one often opt for convenience foods instead of cooking from scratch. This has led to an increase in the availability of prepacked, prepared, and ready-to-cook fruit and vegetable products in the market. While these products are more expensive than loose produce, people are willing to pay extra for the convenience they offer. Expanding the range of tasty, convenient foods with good nutritional value could help improve the diet quality for these groups. CLASSIFICATION OF VEGETARIANISM