Vitamin/mineral supplement use: a telephone survey of adults in the United States.

Vitamin/mineral supplement use in the United States was assessed through a national telephone interview survey of an age-stratified random sample of 2,991 adults 16 years old and older. A vitamin/mineral supplement was defined as any product containing one or more of 33 specific vitamins, minerals, or "miscellaneous dietary components." Excluding pregnant/lactating women, 39.9% of the population consumed one or more supplements. Of those users, 52.4% consumed one supplement only; 10.9% consumed five or more (up to a maximum of 14 separate products). Confirming other research, above-average consumption of supplements occurred in the western United States. The most widely consumed product type was the single vitamin/miscellaneous dietary component (45.2% of supplement users). Vitamin C, either alone or in combination with other nutrients, was the most widely consumed nutrient (90.6% of supplement users). Use of supplements was more prevalent among women than among men in each of the three age groups examined: 16 to 24 years, 25 to 64 years, and 65 years and older. Although consumption of the B vitamins was more widespread among women than among men, more men than women consumed zinc, iodine, copper, magnesium, and manganese. There was a wide range of intake of both vitamins and minerals, which extended to 10 to 50 times the RDAs for individual nutrients.