Should people consider taking vitamin D supplements? If so, who might benefit most from supplements?
Because we may need more vitamin D than most people get in typical diets, and because of the potential downsides of excessive sun exposure, supplementation may be warranted. It may turn out that most people may benefit from supplements. Several groups are at risk for vitamin D deficiency or less-than-adequate intakes-in particular, the elderly, dark-skinned individuals, obese individuals, and those who avoid the sun. People who live in more northern latitudes (such as Boston, Mass., Milwaukee, Wis., or Portland, Ore. ) can only make vitamin D from March through September; supplies stored from summer sun exposure must last for many months, and by late winter, most of these individuals may be deficient. Although definitive evidence is not available currently, supplements of at least 1,000 to 2,000 IU per day of vitamin D may be warranted; look for supplements that contain vitamin D3 (cholecalciferol), rather than vitamin D2 (ergocalciferol), since vitamin D3 is three to four times more p