Vitamin D supplementation did not appear to prevent bone loss in postmenopausal black women, according to a study in the July 25 issue of Archives of Internal Medicine.
Although there is general agreement on the optimal calcium intake recommended for reducing postmenopausal bone loss, and it is recognized that vitamin D is important in calcium maintenance, the optimal intake of vitamin D is controversial, according to background information in the article. Blood levels of 25-hydroxyvitamin D (25-OHD) are the best indicator of vitamin D status, with very low levels leading to rickets and osteomalacia (softening of bones). Black women have lower blood levels of 25-OHD because they synthesize less through skin exposure to the sun.
John F. Aloia, M.D., from Winthrop University Hospital, Mineola, N.Y., and colleagues, conducted a randomized, double-blind trial comparing bone loss in postmenopausal black women taking vitamin D3 supplements and those not taking supplements. Two-hundred-eight healthy black women, aged 50 to 75 years, received either placebo or 20 ìg/day (micrograms per day) of vitamin D3. All participants received calcium supplements to ensure a total calcium intake of 1,200 to 1,500 mg/day. After two years, the vitamin D3 dose was raised to 50 ìg/day. Bone mineral density (BMD) was measured at six-month intervals for three years.