Study takes shine off vitamin D supplements for osteoporosis

NEW YORK • The idea made so much sense it was almost unquestioningly accepted: Vitamin D pills can protect bones from fractures.

After all, the body needs the vitamin for the gut to absorb calcium, which bones need to grow and stay healthy.

But now, in the first large, randomised, controlled study in the United States, funded by the federal government, researchers report that vitamin D pills taken with or without calcium have no effect on bone fracture rates.

The results, published yesterday in The New England Journal of Medicine, hold for people with osteoporosis and even those whose blood tests deemed them vitamin D-deficient.

These results followed other conclusions 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 each year, an editorial published along with the paper has some advice - stop.

"Providers should stop screening for 25-hydroxyvitamin D levels or recommending vitamin D supplements, and people should stop taking vitamin D supplements in order to prevent major diseases or extend life," wrote Dr Steven Cummings, a research scientist at the California Pacific Medical Centre Research Institute, and Dr Clifford Rosen, a senior scientist at the Maine Medical Research Institute.

There are exceptions, they say: People with conditions such as celiac or Crohn's disease need vitamin D supplements, as do those who live in conditions where they are deprived of sunshine and may not get any of the mineral from foods that are routinely supplemented with vitamin D, such as cereals and dairy products.

The bone study's first author and principal investigator, Dr Meryl LeBoff, an osteoporosis expert at Brigham and Women's Hospital, said she was surprised - she had expected a benefit.

But she cautioned that the study did not address the question of whether people with osteoporosis or low bone mass just short of the condition should be taking 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 Sundeep Khosla, a professor of medicine and physiology at the Mayo Clinic, said that since vitamin D "will do little or no harm and may have benefits", he would continue to advise his patients with osteoporosis to take it, recommending the 600 to 800 units a day in the National Academy of Medicine report.

"I will still tell my family and friends who don't have osteoporosis to take a multivitamin a day to make sure they don't get vitamin D-deficient," he said.

Dr Khosla follows that advice himself.

Many multivitamin tablets now contain 1,000 units of vitamin D, he added.

But Dr Cummings and Dr Rosen remain firm, 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 you should take vitamin D."

And Dr Rosen, who signed off on the National Academy of Medicine report, has become a vitamin D therapeutic nihilist.

"I don't believe any more in 600 units," he said. "I don't believe you should do anything."

NYTIMES