Medical Dictionary: Vitamins and Minerals

Most health-conscious people know that it’s important to make healthy food choices and take supplements as necessary to ensure an adequate intake of vitamins and minerals. This medical dictionary covers the terms used in the report, Vitamins and Minerals: What you need to know, and includes details on how to get the vitamins and minerals you need, which vitamins and minerals are necessary and what they do, and how an over-abundance or deficiency of certain supplements can be harmful.

adequate intake (AI): An estimate for the nutritional needs of healthy people used when there are not enough data to support an RDA.

antioxidant: A substance that helps protect the body against destructive free radicals and other unstable molecules by giving up electrons. Antioxidant micronutrients include beta carotene and other carotenoids, vitamin C, and vitamin E.

beta carotene: A precursor that is converted by the body into vitamin A. Beta carotene acts as an antioxidant. It’s found in many green vegetables and dark yellow or deep orange fruits and vegetables.

bioavailability: How quickly and completely a nutrient can be absorbed and used by the body.

carotenoids: Plant and animal pigments that color many fruits and vegetables, including carrots and cantaloupe. Some carotenoids can be converted to vitamin A.

daily value (DV): A measurement, found on the “Nutrition Facts” labels of packaged food, that reports the amounts of specific micronutrients and other key dietary components per serving, stated as a percentage of daily requirements. DVs do not take such factors as age or sex into account, but instead reflect the highest amount of a nutrient an individual might need.

dietary reference intakes (DRIs): A comprehensive set of standards for essential vitamins and minerals based on evidence from scores of observational and clinical studies.

dietary supplements: Vitamins, minerals, herbs, amino acids, enzymes, organ tissues, and a few other substances used to bolster diet. Unlike drugs, they are not regulated by the FDA.

free radicals: Unstable molecules that can alter DNA, oxidize harmful LDL cholesterol, and damage cells and tissues throughout the body by stealing electrons. Free radicals are implicated in aging, cataracts, cancer, and heart disease, among other ills.

homocysteine: A protein by-product that appears to increase the risk for heart disease and strokes when present in the blood at high levels.

micronutrients: Nutrients such as vitamins and minerals that the body requires in fairly small quantities.

phytochemicals: Compounds in plants that affect their taste, color, scent, and other properties. Lycopene, found in tomatoes, is one phytochemical thought to have beneficial effects for people.

precursor: A substance that the body can convert into the active form of a vitamin. One example is beta carotene, which the body can convert into vitamin A as needed.

recommended dietary allowance (RDA): The average daily amount of a micronutrient that will meet the nutritional needs of almost all (97%–98%) healthy people at specific stages of their lives.

tolerable upper intake level (UL): The highest amount of a nutrient deemed likely to have no harmful health effects for almost all healthy people when taken consistently. When people take more than the UL, the risk for ill effects rises along with the dose.