How much of nutrients needed for healthly life?

I gave the glimpse of calorie and nutrition in the earlier posts. Here I would like to give inputs on other basic nutrition informations,DRI, RDA and AI which is being recommended by nutrition boards all over the world.

DRI, RDA, AI :

Dietary Reference Intakes (DRIs) comprise a set of reference values for specific nutrients, each category of which has special uses. The reference values, collectively called the Dietary Reference Intakes (DRIs), include the Estimated Average Requirement (EAR), Recommended Dietary Allowance (RDA), Adequate Intake (AI), and Tolerable Upper Intake Level (UL)

RDA ( Recommended Daily allowance) :

It is the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all (97 to 98 percent) healthy individuals in a particular life stage and gender group.

The RDA are based on scientific knowledge and have been presented by a committee of the Food and Nutrition Board (FNB) of the National Academy of Sciences (NAS). RDA is generally accepted throughout the world as a valid source of information.

Adequate Intake (AI):

The recommended average daily intake level based on observed or experimentally determined approximations or estimates of nutrient intake by a group (or groups) of apparently healthy people that are assumed to be adequate—used when an RDA cannot be determined.

The following Chart gives details for Recommended intakes for Major nutrients.

The general guideline is that approximately 57%, 30%, 13% of energy should come from Carbohydrates, Fats and Protein respectively.

what is Calorie?

Calorie:

A calorie (cal) is the amount of heat energy required to raise the 

temperature of 1g of water 1°C from 14° to 15°C. A kilocalorie (kcal) is the amount of heat required to raise the temperature of 1000g of water 1°C.

When broken down one gram of each carbohydrates ,protein and fat releases 4, 4, 9 kcal of energy respectively.

To calculate the energy available from a food, multiply the number of grams of carbohydrate, protein, and fat by 4,4, and 9, respectively. Then add the results together.

For example, 1 slice of bread with a tablespoon of peanut butter on it contains 16 grams carbohydrate, 7 grams protein, and 9 grams fat :

16g carbohydrate x 4 kcal/g = 64 kcal
7g protein x 4 kcal/g                 = 28 kcal
9g fat x 9kcal/g                           = 81 kcal
Total                                                = 173 kcal

From this information, we can calculate the percentage of kcalories each of the energy nutrients contributes to the total. To determine the percentage of kcalories from fat, for example, divide the 81 fat calories by the total of 173 kcalories:

81 ÷ 173 = 0.468 (rounded to 0.47)
Then multiply by 100 to get the percentage:
0.47 x 100 = 47%

(Reference: Understanding Nutrition 7th Edition by Eleanor Noss Whitney and Sharon Rady Rolfes )

The general guide line is that approximately 57%, 30%, 13% of energy should come from Carbohydrates, Fats and Protein respectively.