Jun

25

Vitamin and Mineral Dietary Supplements

Filed Under Dietary Supplements | Comments Off

Minerals necessary for a health diet are boron, calcium, chromium, copper, iodine, iron, magnesium, manganese, phosphorus, potassium, selenium, and zinc. To prevent illness and death from vitamin and mineral deficiencies, the U.S. government established the recommended dietary allowances (RDAs) in 1943. These values are updated routinely based on new scientific information.
Recently, dietary reference intakes (DRIs) were established by the Institute of Medicine’s Food and Nutrition Board to recommend how much of various nutrients individuals and groups of people should be consuming, not just to avoid deficiency but also to optimize health. Continuing efforts are made to explore the possibility that even higher amounts of certain nutrients may provide additional health benefits. To establish the DRIs, experts in nutrition, dietetics, statistics, nutrition epidemiology, public health, economics, and consumer perceptions reviewed the scientific evidence of safety, efficacy, toxicity, and beneficial properties of vitamins, minerals, and a few non-vitamin/non-mineral substances such as water and fiber.
The DRIs are nutrient-based reference values that include an estimated average requirement (EAR) and an RDA. When there is not enough information to determine an EAR and an RDA, an adequate intake (AI) is established. Many nutrients also have a tolerable upper intake level (UL). Vitamin and mineral dietary supplements may contain a single nutrient (such as vitamin C) or multiple nutrients (such as B-complex or multivitamins).
Doses of vitamins and minerals in dietary supplements vary from levels close to the RDA or AI to several times those levels. The DRIs are used to provide food-based dietary guidance; they are accompanied by national food guides and dietary guidelines for healthy people and provide a basis for food and dietary supplement labels. Although the DRIs and the accompanying guidelines (such as the Dietary Guidelines for Americansand the Food Guide Pyramid) specify daily goals, health professionals use these tools to help people choose diets that provide the recommended nutrients over time.
Several false assumptions have been made regarding vitamin and mineral dietary supplements. For example, vitamin A deficiency causes decreased night vision and, if very severe, blindness. Treating deficient individuals with vitamin A may indeed improve vision. However, many dietary supplements containing vitamin A and beta-carotene (a precursor to vitamin A) claim to “support good eye health.” Some consumers falsely assume that if the deficiency of a vitamin or mineral harms a system or organ, then consuming that vitamin or mineral when the body is not in a deficient state will strengthen that system or organ.
Much of the research on vitamins and minerals has investigated whether dietary supplements are superior to food.
According to two recent scientific publications by Dr. Alice H. Lichtenstein and Dr. Robert M. Russell, both from the Human Nutrition Research Center on Aging at Tufts University, the answer is no. However, most experts do agree that further research is worth pursuing.


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