INTRODUCTION
The concept of balanced diet for different categories of people to have healthful diet is a good approach. Unfortunately an ideal diet cannot be defined. It will not be prudent to advocate a very specific diet or to be very general in our dietary counselling. This has lead to the concept of recommended dietary allowances (RDA). On the basis of height of Indian adult, body weight of 60 kg for reference man and 50 kg for reference women is used in arriving at RDA.
The Philosophy behind the concept of RDA is that individuals of similar age, sex and physical activity levels may have difference nutrient needs. Both genetic and environmental factors are presumably involved. The needs of an individual are rarely known. Thus if an adequate intake of nutrients is to be assured for all individuals the nutrient standard should be established at the upper end of the range of requirements of the group. These standards most often are actually above the need of the most individual. It is seen that groups with relatively low energy intakes – like teenage girls, adult women and elderly persons are usually finding most difficulty in achieving the recommended levels of intake.
The nutrients like calcium, iron, vitamin-B complex, magnesium, zinc, folic acid are generally not consumed in recommended amounts by these groups. The intake of most of the nutrients by those with low purchasing capacity living in both rural and urban areas are far below RDA. One of the most reasonable alternative in this context would be food fortification and consumption of supplements.
Recommended dietary allowance (RDA) are the levels of intake of essential nutrients considered to be adequate to meet the known nutritional needs of all healthy persons. It is also used as a guide to determine the nutritional adequacy of individual diets. The RDA do not cover abnormal problems such as premature birth, inherited metabolic disorders, infections, chronic diseases and use of medications which require special dietary and therapeutic measures.
FACTORS AFFECTING RDA
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Age (infant, adolescent, aged) - An infant requires more protein per kilogram of body weight than adolescent, since their metabolic rate is much faster than that of adolescent.
- Sex (male, female) – Adolescent girls require more iron than adolescent boys in order to replace iron lost during menstruation every month.
- Body size (height, weight, surface area, stature) - Tall heavily built man needs more calories than small statured man, since his body surface area is more than that of the latter.
- Physical state (pregnancy, lactation) - A pregnant women requires more nutritious food than 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 require less calories than a heavy worker, since the former expends less energy than latter during work
USE OF RDA
The RDA of nutrients has a number of practical uses. They are
- To enable government to predict food needs of the population
- To provide basis for food distribution quota
- To guide agricultural planning policy
- To guide policy of food export and import.
- To guide planning of nutritionally adequate diets of inmates of larges catering establishment such as hospitals, hostels, hostels, army canteen, etc.,
- To evaluate the findings of food consumption surveys of various population groups.
- To evaluate the adequacy of food supplies in relation to nutritional needs
- To develop and evaluate new products developed by the food industry.
- To establish guidelines for labelling of food from the nutritional standpoint
- To develop nutrition education programmes.
RECOMMENDED DIEATRY ALLOWANCES FOR INDIANS <- (Click here to view )
FOOD REQUIREMENTS AND ADEQUATE DIETS FOR VULNERABLE GROUPS <- (Click here to view )
Source
Sriramachandrasekharan, M.V and Ravichandran, M. 1999.Principles of Human Nutrition. Lotus Publishers, Tirunelveli.
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