Study casts more doubt on use of high-dose vitamin D pills

Taking a higher dose of vitamin D to protect your bones isn't necessary if you are a healthy middle-aged or older adult with no existing bone disease or vitamin D deficiency, a new study found.

Vitamin D is needed by the body to fully absorb calcium and phosphorus from food.

Taking 2,000 IU (international units) a day of supplemental vitamin D3 without calcium over the course of more than five years did not reduce hip, wrist or pelvic fractures when compared with taking a daily placebo, according to the study published Wednesday in The New England Journal of Medicine.

It’s the latest in a string of disappointments about a nutrient once hoped to have wide-ranging protective effects. That same study of nearly 26,000 people already had found that popping lots of vitamin D pills didn’t prevent heart disease, cancer or memory loss either.

And while getting enough vitamin D is important for strong bones, “more is not better,” said Dr. Meryl LeBoff of Boston's Brigham and Women’s Hospital, the study's lead author.

An estimated third of Americans 60 and older take the supplements and more than 10 million blood tests for vitamin D levels are performed annually -- despite years of controversy over whether the average older adult needs either.

The newest findings -- added to other trials with similar results -- should end that debate, wrote Drs. Steven Cummings of California Pacific Medical Center and Clifford Rosen of Maine Medical Center Research Institute in a commentary in the medical journal.

“People should stop taking vitamin D supplements to prevent major diseases” -- and doctors should stop the routine screenings that fuel concern, the pair concluded. They weren’t involved in the latest study.

Just how much vitamin D should people get? The U.S. recommends 600 to 800 international units a day to ensure that everyone, young and old, gets enough. While our skin makes vitamin D from sun exposure, that can be tougher in winter. Milk and certain other foods are fortified with the nutrient to help.

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