Rethinking vitamin D
I’ve been following the Vitamin D story since it first began to emerge a decade or so ago, and I’ve routinely taken Vitamin D supplements. My doctor tested my Vitamin D levels and pronounced himself pleased. But then I see this story by Gina Kolata in the NY Times:
The very high levels of vitamin D that are often recommended by doctors and testing laboratories — and can be achieved only by taking supplements — are unnecessary and could be harmful, an expert committee says. It also concludes that calcium supplements are not needed.
The group said most people have adequate amounts of vitamin D in their blood supplied by their diets and natural sources like sunshine, the committee says in a report that is to be released on Tuesday.
“For most people, taking extra calcium and vitamin D supplements is not indicated,” said Dr. Clifford J. Rosen, a member of the panel and an osteoporosis expert at the Maine Medical Center Research Institute.
Dr. J. Christopher Gallagher, director of the bone metabolism unit at the Creighton University School of Medicine in Omaha, Neb., agreed, adding, “The onus is on the people who propose extra calcium and vitamin D to show it is safe before they push it on people.”
Over the past few years, the idea that nearly everyone needs extra calcium and vitamin D — especially vitamin D — has swept the nation.
With calcium, adolescent girls may be the only group that is getting too little, the panel found. Older women, on the other hand, may take too much, putting themselves at risk for kidney stones. And there is evidence that excess calcium can increase the risk of heart disease, the group wrote.
As for vitamin D, some prominent doctors have said that most people need supplements or they will be at increased risk for a wide variety of illnesses, including heart disease, cancer and autoimmune diseases.
And these days more and more people know their vitamin D levels because they are being tested for it as part of routine physical exams.
“The number of vitamin D tests has exploded,” said Dennis Black, a reviewer of the report who is a professor of epidemiology and biostatistics at the University of California, San Francisco.
At the same time, vitamin D sales have soared, growing faster than those of any supplement, according to The Nutrition Business Journal. Sales rose 82 percent from 2008 to 2009, reaching $430 million. “Everyone was hoping vitamin D would be kind of a panacea,” Dr. Black said. The report, he added, might quell the craze.
“I think this will have an impact on a lot of primary care providers,” he said.
The 14-member expert committee was convened by the Institute of Medicine, an independent nonprofit scientific body, at the request of the United States and Canadian governments. It was asked to examine the available data — nearly 1,000 publications — to determine how much vitamin D and calcium people were getting, how much was needed for optimal health and how much was too much.
The two nutrients work together for bone health…