I've heard that vitamin D can help build strong bones. How much vitamin D do I need and what's the best way to get it?
Under the direction of Douglas P. Kiel, M.D., M.P.H., scientists in the Musculoskeletal Research Program at the Institute for Aging Research showed that higher doses of vitamin D can lower the risk of falls and fractures in older adults living in nursing homes. They found that residents who took 800 International Units (IU) of vitamin D daily were 72 percent less likely to fall than seniors getting lower amounts or no vitamin D.
Current recommendations call for 200 IU of vitamin D for people under 50; 400 IU for people 51 to 70; and 600 IU for those over 71; however, these recommendations are being revised. Experts recommend at least 800 IU per day for seniors, and they say there are no adverse side effects from vitamin D doses of 1,000 to 2,000 IU per day.
Dr. Douglas P. Kiel says: Vitamin D is a fat-soluble vitamin that is found in very few foods. It is, however, added to milk and some juices, and is available as a dietary supplement.
Essential for maintaining normal blood levels of calcium and phosphorus, vitamin D also aids in the absorption of calcium, which helps to form and maintain strong bones, and in the promotion of bone mineralization.
Without adequate intake of vitamin D, bones can become weak. Vitamin D deficiency in adults can cause osteomalacia, a softening of the bones due to defective bone mineralization. In children, vitamin D deficiency can cause rickets, which potentially can lead to fractures and deformity.
Foods like salmon, mackerel and tuna are high in vitamin D. Milk is fortified with 100 international units (IU) of vitamin D per 8-ounce serving. Ten to 15 minutes of sunlight three times a week is sufficient to produce the body's vitamin D requirements. The skin produces vitamin D in response to the sun's ultraviolet rays; however, with aging, the skin is less efficient in producing vitamin D from sunlight. Dietary supplements are a safe and reliable source of vitamin D. Most multivitamins are fortified with 400 IU of vitamin D.
Douglas P. Kiel, M.D., M.P.H., is a staff geriatrician at Hebrew Rehabilitation Center and director of medical research and co-director of the Musculoskeletal Research Program at the Institute for Aging Research. A graduate of Duke University, Dr. Kiel earned his medical degree at the University of North Carolina School of Medicine and his master's in public health from the Boston University School of Public Health. He is an associate professor of medicine at Harvard Medical School.
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