Are You Getting Enough Vitamin D?
Vitamin D helps form your teeth and bones and helps maintain normal blood levels of calcium and phosphorous, which strengthen bones. Research also shows that vitamin D supplementation lowers the rate of bone resorption and boosts bone mineral density.
Current vitamin D recommendations are 200 international units (IU) for people ages 1–50, 400 IU for people ages 51–70, and 600 IU for people ages 71 and older. However, there is some evidence that we need more vitamin D than the currently recommended levels. With this in mind, some experts suggest getting as much as 800–1,000 IU of vitamin D per day. (But keep your daily intake below 2,000 IU, as too much of this vitamin can be dangerous.)
Yet there is increasing evidence that many Americans don't even get the minimum requirements. One 2004 survey found that two in three Americans between ages 51 and 70 fall short of the current target for vitamin D. The situation is even worse for older people, with nine in 10 not getting enough of the vitamin. Because vitamin D is made in the skin after exposure to sunlight, the problem is particularly pronounced in people who wear sunscreen all the time or live above 40 degrees latitude (in Boston and Detroit, for example), where the winter sunlight isn't strong enough to enable you to produce enough vitamin D.
A 2002 study in the American Journal of Clinical Nutrition noted that 42 percent of African-American women ages 15–49 had a vitamin D deficiency compared with 4 percent of Caucasian women in the same age group. Worse, close to one-third of the African-Americans had a deficiency despite taking adequate amounts of vitamin D supplements. That suggests current recommendations for the vitamin may not be high enough for some women. Women who drank milk or ate fortified cereal at least three times a week, lived in rural areas, or used oral contraceptives were less likely to suffer deficiency. Other research has shown that dark skin and waning sunlight in fall and winter make vitamin D deficiency more likely to occur.
If you’re not getting enough vitamin D, some good food sources of the vitamin include fortified milk or margarine, fortified cereals, and fatty fish. Exposure to sunlight also enables the body to produce vitamin D.
Source: Vitamins and Minerals: What You Need to Know. Copyright © by Harvard University. All rights reserved.