Vitamins and minerals play an essential part in meeting your body's daily needs, but eating a diet with adequate amounts of all vitamins and minerals can be a challenge. With the help of supplements and fortified foods, however, this challenge need not be insurmountable. While generally beneficial, the use of such supplements and fortified foods may present health issues if you exceed the tolerable upper limits for vitamins and minerals.
Tolerable Upper Limits
The University of Maryland Medical Center defines a tolerable upper limit, or UL, as the maximum amount of a given vitamin or mineral that has been determined to be safe for 98 percent of a certain population. According to the Institute of Medicine's Food and Nutrition Board, ULs vary depending on your age and sex, with different ULs recommended for pregnant and lactating women. While ULs may differ for certain individuals, they are generally divided into seven age ranges: infants under 6 months, infants between 6 and 12 months, children from 1 to 3, children from 4 to 8, preteens from 9 to 13, teenagers from 14 to 18, and adults over the age of 18.
Vitamin ULs
For adult men and women who are neither pregnant nor lactating, the Institute of Medicine has determined the ULs of a number of vitamins. For water-soluble vitamins, such as E and C, there is little danger of overconsumption, thus resulting in ULs nearly 100 times greater than the recommended daily intake. For those with potentially adverse side-effects, such as vitamin A, the UL is slightly more than three times the recommended daily intake. As determined by the Institute of Medicine, the daily ULs for vitamins are: 3 mg for vitamin A; 2 g for vitamin C; 100 micrograms, or mcg, for vitamin D; 1 g for vitamin E; 35 mg for niacin; 100 mg for vitamin B6; 1 mg for folate; and 3.5 g per day for choline.
Mineral ULs
Similar to vitamins with potentially toxic effects, the ULs for most minerals are generally no more than five times your recommended daily intake. For adults, the Institute of Medicine recommends these daily ULs: 2.5 g of calcium for people between 19 and 50, and 2 g for those over 50; 10 mg of copper; 10 mg of fluoride; 1.1 mg of iodine; 45 mg of iron; 350 mg of magnesium; 11 mg of manganese; 2 mg of molybdenum; 4 mg of phosphorous for under 70, and 3 mg for those over the 70; 400 mcg of selenium; 40 mg of zinc; 2.3 g of sodium; and 3.6 g of chloride.
ULs Not Determinable
Because of a lack of data on their adverse effects and concern over your ability to handle excessive amounts, the Institute of Medicine recommends that you not use supplements for a number of vitamins and minerals. As such, food should be your only source of the mineral chromium as well as vitamin K, thiamin, riboflavin, vitamin B12, pantothenic acid, biotin, and carotenoids for those who do not suffer from vitamin A deficiency.
References
- University of Maryland Medical Center: Vitamins -- Introduction
- National Academy of Sciences: Institute of Medicine: Food and Nutrition Board: Dietary Reference Intakes: Recommended Dietary Allowances and Adequate Intakes
- National Academy of Sciences: Institute of Medicine: Food and Nutrition Board: Dietary Reference Intakes: Tolerable Upper Intake Levels
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