For years, doctors told menopausal women to stave off osteoporosis with calcium and vitamin D supplements—now, a government panel says the practice may be harmful.
The U.S. Preventive Services Task Force said Tuesday that it "recommends against" low-dosage supplements of vitamin D and calcium for the prevention of fractures in postmenopausal women, saying that there's no evidence it prevents bone fractures and may increase the likelihood of kidney stones.
For men and younger women, the task force said there was inconclusive evidence to recommend using the supplements.
Experts worry that the recommendations are likely to confuse people, because the task force said they only had enough information to recommend against taking low dosage supplements of calcium and vitamin D, not higher doses.
"I think it's going to continue to be a bit confusing for the public about exactly what they're supposed to do," says Kathleen Cody, executive director of American Bone Health. "If it sounds like less is not good, they might think more is better."
Kirsten Bibbins-Domingo, a doctor who works with the U.S. Preventative Task Force, says that the recommendation comes after more than a year of research and that it's constantly reviewing new studies. Tuesday's recommendation is a draft—the organization will take public input before making a final one later this year.
"There's one clear recommendation and a lot of other areas where we don't have enough evidence to say one way or the other," Bibbins-Domingo says. "What we can say in this case is that there's no evidence of benefit and in one case [with postmenopausal women], there's a small but measurable harm with the increased risk of kidney stones."
The task force has made waves a couple times over the past few years: It recently said prostate cancer screenings for otherwise healthy men are likely to do more harm than good. They also recently released a report saying women between 50 and 74 should get mammograms every other year rather than annually.
Bibbins-Domingo says there are many ongoing studies examining vitamin D supplements and, if necessary, the group won't hesitate to reverse its decision.
For now, both Bibbins-Domingo and Cody say patients are better off if they get their daily recommended calcium and vitamin D from their diet.
"Some people think that if one pill is good, then two pills is better. That's definitely not the case with calcium," Cody says.
But Cody says for lactose-intolerant people, young girls, and women over 70 who are at higher risk of having bone problems, supplements might be the only option.
"When you read the [task force's] report, three of the conclusions have insufficient evidence to make any recommendation," she says. "I think the bottom line is that people should try to get their calcium from their diet, but if they can't, they need to talk to their doctor about supplementation."
Jason Koebler is a science and technology reporter for U.S. News & World Report. You can follow him on Twitter or reach him at firstname.lastname@example.org