The sunshine vitamin offers a broad range of benefits—from boosting bone and muscle strength to offering protection against cancer and diabetes. Unfortunately, the diet is a poor source of vitamin D, and dark skin filters out much of the sun's vitamin-producing ultraviolet light. To achieve healthy concentrations of vitamin D, therefore, many African-American women may need hefty daily supplements, a new study finds.
Researchers at the Winthrop University Hospital in Mineola, N.Y., recruited 208 postmenopausal black women for a 3-year trial during which half received large daily doses of vitamin D.
Increasingly, nutrition scientists advocate at least 75 nanomoles of vitamin D per liter of blood as a minimum target value for health, notes John F. Aloia, an endocrinologist and coauthor of the study.
Even after 2 years of supplementation with 800 international units of vitamin D daily—twice the recommended daily intake—treated women attained only 88