The idea made so much sense that it was almost unquestionably accepted: Vitamin D pills can protect bones from fractures. After all, the body needs the vitamin for the intestines to absorb calcium, which bones need to grow and stay healthy.
But now, in the first large, federally funded, randomized controlled trial in the United States, researchers report that vitamin D pills taken with or without calcium have no effect on bone fracture rates. The results, published Thursday in The New England Journal of Medicine, hold true for people with osteoporosis and even those whose blood tests found them deficient in vitamin D.
These results followed other findings from the same study that found no support for a long list of purported benefits of vitamin D supplements.
So for the millions of Americans who take vitamin D supplements and the labs that do more than 10 million vitamin D tests a year, an editorial published alongside the journal has one piece of advice: Stop.
“Providers should stop tracking 25-hydroxyvitamin D levels or recommend vitamin D supplements, and people should stop taking vitamin D supplements to prevent serious illness or prolong life,” wrote Dr. Steven R. Cummings, a researcher at the California Pacific Medical Center Research Institute, and Dr. Clifford Rosen, a senior scientist at the Maine Medical Research Institute. Dr. Rosen is editor of The New England Journal of Medicine.
There are exceptions, they say: People with conditions like celiac or Crohn’s disease need vitamin D supplements, as do those who live in conditions where they are deprived of sunlight and may not get any minerals from foods that are routinely supplemented with vitamin D. D, such as cereals and dairy products.
Getting into such a severe state of vitamin D deprivation is “very difficult to do in the general population,” Cummings said.
The two scientists know that in making such strong claims they are facing vitamin sellers, testing labs and advocates who claim that taking vitamin D, often in large amounts, can cure or prevent a wide variety of diseases and even help people to live more.
Doctors usually check vitamin D levels as part of routine blood tests.
The study involved 25,871 participants — men age 50 and older and women age 55 and older — who were either assigned to take 2,000 international units of vitamin D a day or a placebo.
The research was part of a comprehensive vitamin D study called VITAL. It was funded by the National Institutes of Health and began after a group of experts convened by what is now the National Academy of Medicine, a non-profit organization, examined the health effects of vitamin D supplements and found little evidence. Members of the expert panel were supposed to have a minimum daily requirement for the vitamin, but they found most of the clinical trials that studied the subject to be inadequate, causing them to ask if there was any truth to the claims that vitamin D improved health.
The prevailing opinion at the time was that vitamin D was likely to prevent bone fractures. The researchers thought that as vitamin D levels dropped, parathyroid hormone levels would increase at the expense of bones.
Rosen said those concerns led him and other members of the National Academy of Medicine expert group to set what he called the “arbitrary value” of 20 nanograms per milliliter of blood as the target for vitamin D levels and to advise people to obtain 600 to 800 international units of vitamin D supplements to achieve this goal.
Laboratories in the United States arbitrarily set 30 nanograms per milliliter as the cut-off point for normal vitamin D levels, a reading so high that nearly everyone in the population would be considered vitamin D deficient.
The supposed relationship between vitamin D and parathyroid levels did not hold up in subsequent research, Rosen said. But uncertainty continued, so the National Institutes of Health funded the VITAL study to get some solid answers about vitamin D’s relationship to health.
The first part of VITAL, published earlier, found that vitamin D did not prevent cancer or cardiovascular disease in study participants. Nor did it prevent falls, improve cognitive functioning, reduce atrial fibrillation, change body composition, reduce migraine frequency, improve stroke outcomes, protect against macular degeneration, or reduce knee pain.
Another large study in Australia found that people who took the vitamin no longer lived.
JoAnn Manson, chief of preventive medicine at Brigham and Women’s Hospital at Harvard Medical School and leader of the pivotal VITAL study, said the study was so large that it included thousands of people with osteoporosis or with vitamin D levels in a range considered to be low or low. insufficient”. This allowed the researchers to determine that they also received no fracture reduction benefit from the supplement.
“This will surprise many,” said Dr. Manson. “But it appears that we only need small to moderate amounts of the vitamin for bone health. Larger amounts do not confer greater benefits.”
The first author and principal investigator of the bone study, Dr. Meryl S. LeBoff, an osteoporosis specialist at Brigham and Women’s Hospital, said she was surprised. She expected a benefit.
But she cautioned that the study did not address the question of whether people with osteoporosis or low bone mass should take vitamin D and calcium along with osteoporosis medications. Professional guidelines say they should take vitamin D and calcium, and she will continue to adhere to them in her own practice.
Dr. Dolores Shoback, an osteoporosis specialist at the University of California, San Francisco, will also continue to advise patients with osteoporosis and low bone mass to take vitamin D and calcium.
It is “a simple intervention and I will continue to prescribe,” she said.
Others go a little further.
Dr. Sundeep Khosla, a professor of medicine and physiology at the Mayo Clinic, said that because vitamin D “will do little to no harm and may have benefit,” he would continue to advise his osteoporosis patients to take it, recommending 600 to 800 units per day. day in the report of the National Academy of Medicine.
“I’m still going to tell my family and friends who don’t have osteoporosis to take a multivitamin a day to make sure they don’t become vitamin D deficient,” he said.
Dr himself. Khosla follows this advice. Many multivitamin tablets now contain 1,000 units of vitamin D, he added.
But Dr. Cummings and Dr. Rosen remain steadfast, even questioning the very idea of a vitamin D deficiency for healthy people.
“If vitamin D doesn’t help, what is a vitamin D deficiency?” Dr. Cummings asked. “That implies that you must take vitamin D.”
And Dr. Rosen, who signed the National Academy of Medicine report, became a therapeutic vitamin D nihilist.
“I no longer believe in 600 units,” he said. “I don’t think you should do anything.”