Calcium + D prevent cancer - Quick Studies - Brief Article

Nutrition Action Healthletter, Jan-Feb, 2004

Getting enough calcium and vitamin D lowers the risk of precancerous colon polyps, but only in people who get enough of both nutrients.

For four years, researchers gave either calcium supplements (1,200 mg a day) or a placebo to roughly 800 people who had already had at least one colon polyp removed. Among people who started the study with blood vitamin D levels at the lower end (29.1 nanograms per milliliter or less), the calcium supplements did nothing.

But among people who had higher blood vitamin D levels, calcium cut the risk of new colon polyps by about 30 percent. (Only blood levels of 25-hydroxyvitamin D, not 1,25-dihydroxyvitamin D, were linked to the risk of polyps.) However, above-average levels of vitamin D didn't reduce the risk of polyps in people who took the placebo.

What to do: Get the recommended levels of calcium (1,200 mg a day if you're over 50 and 1,000 mg for younger adults) and vitamin D (600 IU a day if you're over 70, 400 IU if you're 51 to 70, and 200 IU for younger adults). You can also get vitamin D from sunlight (see NAH, December 2003).

Journal of the National Cancer Institute 95: 1765, 2003.