Nutrition overview

<strong>Nutrition</strong><strong>Nutrition</strong>: the biochemical and physiological process by which an organism uses food to support its life

  • the process of nourishing the body

<strong>Nutrients</strong><strong>Nutrients</strong>: the constituents of food necessary to sustain the normal functions of the body.

  • some provide energy
  • most help to build cells and tissues, and/or regulate body processes
  • no single food supplies all the nutrients the body needs to function

\ <strong>Diet</strong><strong>Diet</strong>: the customary amount and kind of food and drink a person takes in day to day.

All energy is provided by the three classes of <strong>macro−nutrients</strong><strong>macro-nutrients</strong> (intake needed is larger):

  • fats
  • carbohydrates
  • protein

\ Nutrients needed in lesser amounts are called <strong>micro−nutrients</strong><strong>micro-nutrients</strong>

They include:

  • vitamins
  • minerals
  • essential fatty acids
  • essential amino acids

<strong>Calorie</strong><strong>Calorie</strong>: unit of energy, the amount of heat necessary to raise the temperature of 1kg of water 1°C

^^Fats^^: 9 cal/g

^^Carbohydrate and protein:^^ 4 cal/g

Dietary Reference Intakes

<strong>DietaryReferenceIntakes(DRI):</strong><strong>Dietary Reference Intakes (DRI):</strong> estimates of the amounts of nutrients required to prevent deficiencies and maintain optimal health and growth.

  • Th DRI establishes upper limit on the consumption of some nutrients, unlike the Recommended Dietary Allowances (RDA).

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Definition

The DRI consists of ^^4 dietary reference standards^^ for the intake of nutrients designated for ==specific age groups, gender, and physiologic states.==

  1. Estimated Average Requirement
  2. Recommended Dietary Allowance
  3. Adequate Intake
  4. Tolerable Upper Intake Level

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Estimated Average Requirement (EAR)

The average daily nutrient intake level estimated to meet the requirement of ==one half of the healthy individuals in a particular life stage (age) and gender group.==

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Recommended Dietary Allowance (RDC)

The average daily nutrient intake level that is sufficient to meet the requirement of ==nearly all (97% - 98%) individuals in a particular life stage and gender group.==

  • RDC is not the minimal requirement for healthy individuals, but rather it provides a margin of safety for most individuals
  • the EAR serves as the foundation for setting the RDA
  • %%RDA = EAR + 2 SD%% (standard deviation)

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Adequate Intake (AI)

An Adequate Intake (AI) is set instead of an RDA if there is ==insufficient scientific evidence== available to calculate an EAR of RDA.

  • based on estimates of nutrient intake by a group/s of apparently healthy people

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Tolerable Upper Intake Level (UL or TUL)

The ==highest== average daily intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population.

  • as intake increases above the UL, the potential risk of adverse effects may increase
  • useful because of the increased availability of fortified foods and the increased use of dietary supplements
  • for some nutrients, there may be insufficient data on which to develop a UL

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Using the Dietary Reference Intakes

  • most nutrients have a set DRI
  • usually a nutrient has an EAR and a corresponding RDA
  • most are set by %%age%% and %%gender%%, and are influenced by special factors (e.g. %%pregnancy and lactation%% in women)
  • when data are not sufficient to estimate an EAR (or RDA), and AI is designed
  • intakes at or above the RDA can be considered adequate
  • intakes above the AI can be considered adequate
  • intakes between the UL and the RDA can be considered to have no risk for adverse effects
  • intakes over the UL show risk for adverse effects
  • the DRI does not include any special needs of the sick, it is designed to meet the nutritional needs of the healthy

 

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