Research has repeatedly failed to find significant benefits from taking vitamin supplements, and some have even found them to cause some harm. Now, research reported in the Journal of the American Medical Association has shown that vitamin D supplements do not prevent bone fractures.
The scientists assessed data from 33 studies, which included 50,000 participants over the age of 50. They determined that people who took supplements of vitamin D were no less likely to suffer bone fractures than those who did not take them. Incredibly, in some groups, like those who already had certain levels of vitamin D when they began supplement intake, it was harmful.
"In the US, no dietary supplements are pre-screened for safety and efficacy," S. Bryn Austin, a professor of behavioral sciences at the Harvard T.H. Chan School of Public Health, told Business Insider. "What that means is the FDA and consumers have no way to know if what's in the bottle or box is what's on the label. There's no way to know for sure that what's in the product is safe."