Vitamin D might not be all it’s cracked up to be.
A new study published Thursday in The Lancet - Diabetes & Endocrinology asserts the supplement does not play a serious role in reducing the risk of diseases or fractures. The findings conclude that any future studies on the vitamin are futile.
“So there seems little justification currently for prescribing vitamin D to prevent heart attack, stroke, cancer, or fractures in otherwise healthy people living in the community,” lead researcher Mark Bolland of the University of Auckland told the Globe and Mail.
Vitamin D has long been thought of as a cure-all for a host of diseases and disorders, including heart disease, stroke, cerebrovascular disease, cancer and fractures. But the latest study, which reviewed data from 40 previous studies on the effectiveness of vitamin D, shows that "healthy people are very unlikely to get a benefit from it," Bolland told USA Today.
This isn’t the first study to question the effects of vitamin D. Last year, a study published in the Lancet also conducted by Bolland found that vitamin D did not reduce the risk of osteoporosis. A separate study published in December by French researchers found that the vitamin did not lower disease rates.
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“Existing evidence does not lend support to the commonly held belief that vitamin D supplementation in general prevents osteoporosis, fractures and non-skeletal diseases,” Karl Michaelsson, a professor of orthopedics at Uppsala University in Sweden, said in a comment accompanying the article.
The new study focused on randomized trials where people were given vitamin D or placebo pills and followed to see if their health changed. The results showed that giving people vitamin D did not prevent heart attacks, strokes or cancer or reduce the risk of bone fractures equivalent to 15 percent. The study also concluded there was “uncertainty as to whether vitamin D with or without calcium reduces the risk of death."
Michael Holick, a professor of medicine at Boston University and proponent for vitamin D, disagrees with the study’s findings. He says the studies' administered doses were too low to garner accurate results. Instead of 200 to 400 international units (IU) a day, he believes higher doses, such as such as 2,000 IU a day, will show the supplement’s benefits.
It's unknown if the vitamin D industry – which makes $600 million a year -- will be affected.
"The debate is likely to continue," Michaëlsson said. "The impression that vitamin D is a sunshine vitamin and that increasing doses lead to improved health is far from clear."