Postmenopausal women should not take low supplemental doses of vitamin D and calcium in the hopes of preventing bone fractures, according to draft recommendations issued Tuesday by the United States Preventive Services Task Force.
This recommendation is likely to stun the millions of older women who have been taking these supplements for years, believing they will give their bones extra strength as they age.
The independent panel of USPSTF experts reviewed 137 studies — the best evidence on the issue compiled to date — and determined that taking daily supplements of 400 IUs (international units) of vitamin D and 1,000 milligrams of calcium does not prevent fractures. Nor did they find any evidence that the supplements prevent cancer. The supplements do, however, slightly increase a woman’s risk of developing kidney stones.
The USPSTF experts also said there is little evidence that low doses of vitamin D and calcium help prevent fractures in men or younger women.
None of these recommendations apply to individuals with diagnosed osteoporosis.
In addition, the panel looked at whether larger supplemental doses of the two nutrients prevented fractures and decided the evidence is inconclusive. Last week, however, the group recommended that elderly people who have been identified by their doctors as being at increased risk of falling should take vitamin D supplements — and increase their exercise or physical therapy — to help lower that risk.
Supports earlier recommendations
The USPTF findings support those of another group of independent experts, the Institute of Medicine (IOM). In 2010, the IOM reported that vitamin D deficiency among Americans was overestimated and recommended supplements only to people with true deficiencies. According to the IOM, most Americans need no more than 600 to 800 IUs of vitamin D and 1,000 to 1,200 milligrams of calcium daily to keep their bones healthy (the higher of those amounts are for people over the age of 70). Those levels, the IOM experts stressed, are easily attained by most people through the food that they are already eating and through exposure to sunlight (yes, even in sun-challenged northern latitudes).
Expect pushback against these latest USPTF recommendations, just as there was against the panel’s earlier recommendations regarding routine prostate-specific antigen (PSA) testing for prostate cancer and routine annual mammograms for breast cancer. Supplements are a $30-billion-a-year industry in the United States. Sales of vitamin D supplements alone skyrocketed from $50 million in 2005 to $550 million in 2010.
You can read the USPSTF’s draft recommendations here. They are open for public comment until July 10.