A combination of vitamin D and calcium has long been recommended as a way for elderly people to ward off both bone fractures and cancer, but new research suggests that it’s only effective in one of these areas. According to Reuters Health, American scientists have found that medical evidence suggests vitamin D—with or without the help of calcium—is effective only in preventing fractures.
This comes as a blow for those hoping the supplement will help prevent them from developing cancer.
“It turns out that as a group, all of the micronutrient supplements have been disappointing,” said Michael Pollak of the McGill University cancer prevention division. “Even one of the best candidates, which is vitamin D, is certainly no slam dunk.”
The report was released by the U.S. Preventive Services Task Force on Monday. A meta-analysis, the study looks at 19 separate experiments on vitamin D with or without calcium. In only one of these studies was a form of cancer protection found—for postmenopausal women taking vitamin D and calcium. But that study was small, Reuters said, and the larger studies found no benefits for participants.
Lead researcher Mei Chung of the Tufts Medical Center in Boston told Reuters Health that she had no confidence in the findings in the trial that suggested vitamin D protected against cancer “because they could be chance findings.” Indeed, the report even showed that women taking the supplement had higher rates of kidney and bladder stones.
“You can have too much of a good thing,” Pollak agreed.
