Nutrition 1

Nutrition
Nutrients are the constituents of food necessary to sustain the normal functions of the body. All energy is provided by three classes of nutrients: fats, carbohydrates, protein, and in some diets, ethanol. The intake of these energy-rich molecules is larger than that of the other dietary nutrients. Therefore, they are called macronutrients. Those nutrients needed in lesser amounts, such as vitamins and minerals, are called micronutrients.
I. DIETARY REFERENCE INTAKES(DRIs)
A. Definition of the DRIs :
Estimates of the amounts of nutrients required to prevent deficiencies and maintain optimal health. The DRIs establish upper limits on the consumption of some nutrients, and incorporate the role of nutrients in lifelong health, going beyond deficiency diseases.
The DRIs consist of four dietary reference standards for the intake of nutrients designated for specific age-groups, physiologic states, and sexes .
1. Estimated Average Requirement (EAR): The EAR is the average daily nutrient intake level estimated to meet the requirement of one half the healthy individuals in a particular life stage and gender group. In other words EAR is the intake at which the risk of inadequacy is 50%. It is useful in estimating the actual requirements in groups and individuals.
2.Recommended Dietary Allowance (RDA): The RDA is the average daily dietary intake level that is sufficient to meet the nutrient requirements of nearly all (97 to 98 percent) individuals in a life stage and gender group. In other words RDA is the intake at which the risk of inadequacy is 2-3% .The RDA is not the minimal requirement for healthy individuals; rather, it is intentionally set to provide a margin of safety for most individuals. The EAR serves as the foundation for setting the RDA.