The message on vitamin D is pretty clear if you talk to Dr. JoAnn E. Manson, M.D., chief of the preventive medicine division at Brigham and Women’s Hospital in Boston, who is leading the largest clinical trial in the world investigating the potential health benefits of vitamin D. It boils down to this: Curb Your Enthusiasm. At least for the time being. Even in the midst of a hellish winter when you may be tempted to take an extra dose of the so-called “Sunshine Vitamin” for a boost.
In a commentary piece published this week in the Journal of the American Medical Association, Dr. Manson urges caution. She says that even though the public has become smitten with vitamin D, its growing popularity has led to mega-dosing that’s not backed by the current evidence. “More isn’t always better, more is sometimes worse,” Manson said in an interview. “We don’t yet have the answers, so we shouldn’t make assumptions.” But, she adds, in a couple of years, gold-standard evidence on whether higher doses of vitamin D are good for you should be out.
But get on the phone with Dr. Michael F. Holick, Ph.D., M.D., a leading vitamin D proponent, endocrinologist at Boston Medical Center and professor at Boston University School of Medicine, and you’ll get a totally different, but equally clear message. Vitamin D deficiency and insufficiency are far more widespread than certain professional medical groups suggest, Holick says, and dosing at higher levels shows “no evidence of toxicity.”
How did we get here and what’s a patient to do?
Here’s a little background:
In debates over nutrition, vitamin D is one of those supplements that’s drawn both passionate supporters and equally aggressive skeptics over the years. And, like coffee, chocolate and red wine, it’s often the subject of studies that can make your head spin: it’s good for you…until it’s not.
The current vitamin D guidelines from the Institute of Medicine recommend 600 IU’s per day for adults up to 70 years old and 800 IU’s per day for those over 70. “This,” writes Manson in her JAMA piece “is equivalent to 3 to 4 daily servings of fortified foods such as milk, yogurt, soy beverages, orange juice, or cereal, plus fatty fish twice per week. These amounts are adequate for at least 97.5% of U.S. and Canadian residents, she says, and it’s good even in the bleakest, darkest season, “even if you’re in Antartica in winter.” Continue reading