The Government's Recommended Daily Vitamin Requirements

The Dietary Reference Intakes consist of nutrient intake values that can be used to plan and evaluate the diets of healthy people. DRI reports are produced by a U.S. expert panel of the Food and Nutrition Board of the Institute of Medicine working together with scientists from Canada. The DRI committee bases estimates of nutrient needs on scientific evidence after reviewing hundreds of research studies. Recognizing that each person's requirements are unique, the committee provides recommendations for people within groups by age and gender.

Identification

The DRI include the Recommended Dietary Allowances and Adequate Intakes. The RDA reflect the amount of a nutrient considered adequate to meet the needs of most healthy people. If there is not enough scientific evidence to determine an RDA, an AI is set. The AI is the average amount of a nutrient that appears sufficient to maintain health, based on the average amount that healthy people consume. The Estimated Average Requirement represents the amount of a nutrient that supports a specific function in the body for half of the population.

RDA and AI

The RDA and AI fall within a safety range that defines appropriate and reasonable intake levels that are neither deficient nor toxic, according to Eleanor Whitney and Sharon Rolfes in "Understanding Nutrition." The RDA include a generous margin of safety and are not minimum requirements and not meant as optimal requirements for all people. A registered dietitian or other qualified health professional can help determine what adjustments are needed to meet individual requirements.

Upper Intake Levels

Tolerable upper intake levels represent the level beyond which a nutrient is more likely to become toxic. Upper levels guard against over-consuming specific nutrients when taking supplements or fortified foods regularly.

Age Groups

The RDA for vitamins are established for infants under 6 months and infants 6 to 12 months old. The RDA for children are established for ages 1 to 3 and for ages 4 to 8. Vitamin requirements are set separately for males and for females in age-groups defined as 9 to 13 years, 14 to 18 years, 19 to 30 years, 31 to 50 years, 51 to 70 years and above 70 years. Separate recommendations apply to women ages under 18 years, 19 to 30 years and 31 to 50 years who are pregnant and for women in these age-groups who are lactating.

Vitamins

RDA or AI levels are defined by age-group for thiamin, riboflavin, niacin, biotin, panthothenic acid, vitamin B-6, folate, vitamin B-12, choline, vitamin C, vitamin A, vitamin D, vitamin E and vitamin K. Upper intake levels have been established for niacin, vitamin B-6, folate, choline, vitamin C, vitamin A, vitamin D and vitamin E.

RDA or AI levels are also established for the minerals calcium, phosphorus, magnesium, iron, zinc, iodine, selenium, copper, manganese, fluoride, chromium and molybdenum. Upper Intake Levels are defined for those minerals, except for chromium, and are also defined for boron, nickel and vanadium.

Considerations

The RDA are meant to describe the needs of most healthy people. Persons who are malnourished, have a disease, trauma injury or special needs may require more or less than the RDA for specific vitamins. Nutrient goals should be met through a variety of foods. An excess intake of vitamins is not likely when they come from food rather than supplements.