Nutrients and Dietary Reference Intakes (DRIs)

Nutrition

the total processes involved in the intake and utilization of food substances, including ingestion, digestion, absorption, transport, and metabolism

Metabolism

encompasses all chemical processes that occur within a living organism (cell) to maintain life

Nutrients

a substance found in foods that performs one or more physiological/biochemical functions in the body

ex) energy, structural component, growth and development, preventing diseases, regulation

Classifications of nutriets

* Organic vs. inorganic
* Essential vs. nonessential
* Micronutrients vs. macronutrients
* Energy yielding vs. non-energy yielding

Organic vs. inorganic

* Organic nutrients are molecules containing carbon atoms (ex: CHO, fats, proteins, vitamins)
* Inorganic nutrients don’t contain carbon (ex: water, minerals, table salt)

Essential vs. nonessential

* Essential nutrients are substances that must be obtained from the diet, because it is required by and the body can’t make it in the required amounts
* Nonessential nutrients are substances found in the body and used by it to promote health, but not required to be consumed in the diet (ex: cholesterol, creatine)

Essential nutrients

Carbohydrates, lipids, proteins, minerals, vitamins, water

Conditionally essential nutrients

normally nonessential, but they become essential under certain circumstances (ex: age-specific nutrient requirements, pregnancy, chronic disease)

Macronutrients vs. micronutrients

* Macronutrients: to preserve normal body functions, need them in large quantities (more than 1g per day). Examples are CHO, lipids, and proteins
* Micronutrients: need these in small quantities (less than 1g per day). Examples are vitamins and minerals

Energy yielding vs. non-energy yielding

* All macronutrients release energy (CHO 4kcal/g, fats 9kcal/g, proteins 4kcal/g)
* Micronutrients do not release energy
* Alcohol is a toxin, but does yield energy

non-nutrient components

* Added colorants, artificial sweeteners and preservatives, etc.
* Natural microorganisms

Dietary reference intakes

A set of diet reference values to aid individuals in optimizing their health, preventing disease, and avoiding nutrient overconsumption.

* The US and Canada re-estimate these values every 5 years

Estimated average requirement (EAR)

Nutrient intake value estimated to meet the requirement of 50% of healthy individuals in the population

Recommended dietary allowance (RDA)

Average daily nutrient intake level sufficient to meet the nutrient requirement of nearly all (97%) of healthy people

* The EAR plus two standard deviations

Adequate Intake (AI)

Used when scientific evidence is insufficient for an RDA (likely to exceed the actual intake requirements for most individuals in a group)

Tolerable Upper Intake

Preventing overconsumption

Estimated Energy Requirement (EER)

Used to estimate the calorie needs of the average person within a specific height, weight, gender, age, and physical activity pattern

Acceptable Macronutrient Distribution Range (AMDR)

Ranges of macronutrient intake associated with reduced risk of chronic disease while providing recommended intakes of other essential nutrients

Chronic Disease Risk Reduction (CDRR)

characterizes nutrient intakes that are expected to reduce the risk of developing chronic disease

* Ex: sodium (no evidence to suggest a specific Upper Limit, but evidence for high sodium linked to heart disease)