Vitamin D Fervor: Are We Overselling The Sunshine Vitamin? Some preliminary studies link vitamin D to health benefits, and increasingly doctors are suggesting that patients with low levels should take supplements. But some doctors warn that there isn't enough concrete evidence to prove that the vitamin helps reduce the risk of disease.
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Are We Overselling The Sunshine Vitamin?

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Are We Overselling The Sunshine Vitamin?

Are We Overselling The Sunshine Vitamin?

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This is MORNING EDITION from NPR News. I'm Mary Louise Kelly.


And I'm Renee Montagne.

Today in Your Health, we'll hear how doctors neglect proven treatment for one of the deadliest and most common conditions: high blood pressure. That story in a few minutes. Now, let's hear about doctors' growing enthusiasm for vitamin D. NPR's Richard Knox reports on the use of the supplement for a range of ailments, from depression to flu.

RICHARD KNOX: Dr. Cliff Rosen knows a lot about vitamin D. It's necessary for strong bones, and Rosen's a leading bone specialist in Portland, Maine. So, he was surprised when his wife's new physician thought she should be tested for vitamin D deficiency.

Dr. CLIFF ROSEN: She's a runner. She's in great shape. She drinks dairy. She gets a lot of sun exposure.

KNOX: Rosen points out that vitamin D is made by your skin when you're in the sun.

Dr. ROSEN: And so my wife said, well, why do I need to have vitamin D? And the physician just said, that's part of our measurement for wellness, is what your vitamin D level.

KNOX: That's not the only doctor who's jumping on the vitamin D bandwagon. I went up the road to Freeport, Maine and paid a call on a family practitioner named James Donahue.

Dr. JAMES DONAHUE (Family Practitioner): Hi, James Donahue.

KNOX: Yeah, hi.

Dr. DONAHUE: Pleased to meet you. Come on back.

KNOX: How long have you been measuring Vitamin D levels in patients?

Dr. DONAHUE: Aggressively, in about the past year.

KNOX: Right after he went to a conference in Boston.

Dr. DONAHUE: I listened to one of the speakers who was talking about vitamin D research, and came back, and out of curiosity I did the next 10 patients for vitamin D levels. And of the 10 patients, the only patient came up normal was low normal, and everybody was sub-normal. And that's pretty much been my experience when I test.

KNOX: Recently, Donahue hasn't even been bothering to test patients' vitamin D levels. He just goes ahead and says, you should be taking vitamin D.

Dr. DONAHUE: Far and away, the majority of the patients in my patient population are taking vitamin D or paying attention to vitamin D supplementation.

KNOX: The guy who got Donahue and thousands of other U.S. doctors looking for vitamin D deficiency is Dr. Michael Holick of Boston University. He discovered the active form of the vitamin 40 years ago. Lately, he's been beating the drum in medical journals and popular books, including one coming out next month that calls vitamin D deficiency our most common health problem.

Dr. MICHAEL HOLICK (Boston University): Vitamin D is very important for your overall health and well-being.

KNOX: Holick has a long list of ailments he says vitamin D supplements can prevent: osteoporosis, cancer, heart disease, diabetes, multiple sclerosis, depression, Alzheimer's, autism, tuberculosis, even the flu. He also claims success in using high doses of D to treat some conditions, such as a woman who came in with severe muscle pain.

Dr. HOLICK: Found that she was a vitamin D deficient, corrected her vitamin D deficiency, and within two months, she came back to me and said that I've changed her life.

KNOX: Holick also says vitamin D treatments have stopped the progression of multiple sclerosis in several of his patients. But some experts say, not so fast.

Dr. JOANN MANSON (Chief, Preventive Medicine, Brigham and Women's Hospital): We need to keep in mind the lessons of history.

KNOX: That's Dr. JoAnn Manson. She's chief of preventive medicine at Brigham and Women's Hospital in Boston.

Dr. MANSON: It was believed that megadoses of vitamin E, vitamin C, beta-carotene, selenium, folic acid and the B vitamins would confer a large array of health benefits.

KNOX: But it didn't turn out that way. In fact, one large study found, to everybody's surprise, that patients who took beta-carotene had a higher risk of lung cancer.

Manson's just starting a major study, funded by the National Institutes of Health. It'll assign 20,000 Americans to take vitamin D supplements, omega-3 supplements of placebos to see if either nutrient prevents cancer, heart disease or other ailments. But that'll take five years. Meanwhile, the bandwagon's rolling.

Medicare payments for vitamin D tests nearly quadrupled from 2006 and 2008.

Until study results are in, Cliff Rosen, the bone specialist in Portland, Maine, says taking vitamin D is a way to hedge your bets.

Dr. ROSEN: It's a safe enough approach to preventive medicine. The question is: Is it preventive?

KNOX: Rosen and Manson are contributing to a report from the National Institute of Medicine on how much vitamin D people should get. It's due out this summer.

Richard Knox, NPR News.

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