The Latest on DThe solar-powered vitamin is not just for strong bones
I do a lot of public speaking around the country about our research on physical activity and nutrition. These talks give me a chance to catch up on peopleís health concerns. One subject that seems to be on many peopleís minds is vitamin D. What are the best sources? Can it help prevent osteoporosis? How much is enough?
Vitamin D is a fat-soluble vitamin that promotes the absorption of calcium and is therefore particularly important for healthy bones. Older adults need to be especially vigilant in protecting their bones to help prevent the onset of osteoporosis. One out of two older women and one out of five older men can expect to get osteoporosis if they live into advanced age.
New information is emerging all the time about this fascinating vitamin. Research by my colleagues at Tufts and elsewhere suggests that in addition to improving our bone health, vitamin D can preserve our muscle strength and increase our immune function, too. You can get vitamin D from three sources: the sun, the right foods, and supplements.
During the fall and winter months, the sunís rays are neither strong enough nor at the correct angle to stimulate vitamin D synthesis in your skin. If you live in a northern state or province, you will not be able to rely on the sun as your source of vitamin D between October and March.
The results were impressive. While the people in both groups had the same risk of falling, only 6 percent of those who took the supplements suffered fractures, compared with 13 percent who were taking a placebo.
How much should you take?
I recommend choosing a vitamin D supplement that supplies 400 to 700 IU. Donít go above 1,000 IU unless your doctor recommends it, because vitamin D can be toxic at high levels.
Vitamin D is an important part of bone health, but itís just one piece of the puzzle: combining supplementation with good nutrition and adequate calcium intake, exercise, medication management (when necessary), and other lifestyle measures is critical to maintaining a strong and healthy body.
Miriam E. Nelson is director of the John Hancock Center for Physical Activity and Nutrition at Tufts and an associate professor at the Friedman School of Nutrition Science and Policy. She also holds an adjunct appointment at the Tisch College of Citizenship and Public Service. Strong Women, Strong Backs (GP Putnamís Sons), her eighth book in the bestselling Strong Women series, was published in September.