Vitamin D, the so-called sunshine vitamin, has generated a lot of attention in recent years. It has been claimed to benefit a wide variety of diseases, everything from cancer to multiple sclerosis. It is widely used along with calcium for bone health. It is added to milk and prenatal vitamins and is prescribed for breastfed babies. Some doctors are recommending everyone take it for prevention. Some CAM advocates are recommending it as a more natural way to prevent the flu than getting a flu shot.
It has been touted as a panacea; Michael Holick even wrote a book titled The Vitamin D Solution: A 3-Step Strategy to Cure Our Most Common Health Problems. Christiane Northrup praised it, saying “This information can save your life. Really.” (Really? I’m skeptical, and her recommendation is not enough to make me want to read the book.) Then there’s Jeff Bowles’ book The Miraculous Results of Extremely High Doses of the Sunshine Hormone Vitamin D3 My Experiment With Huge Doses of D3 From 25,000 To 50,000 Iu A Day Over A 1 Year Period. That one’s not on my reading list either; the tolerable upper intake level is 4,000 IU a day.
It’s hard to avoid the hype and just examine the actual scientific evidence without any bias. The United States Preventive Services Task Force has tried to do just that. It recently evaluated screening for vitamin D deficiency and concluded that the current evidence is insufficient to recommend either for or against screening. Predictably, their announcement has already led to misunderstandings and protests.
This will be a departure from my usual posts. Several announcements in the news and medical journals have caught my attention recently, and as I delved into the details, I thought I would share them with our SBM readers. Topics include AIDS cures, the continuing danger of polio, eating nuts for longevity, racial differences in vitamin D, and the use of pharmacogenetic testing to guide the dosage of anticoagulant drugs. They are all examples of science-based medicine in action.
Have patients been cured of AIDS?
I read that the HIV virus had returned in patients thought to have been cured by bone marrow transplants, and I mistakenly thought they were referring to the original claim of cure I had read about. Nope, that one still stands. (more…)
A Walmart ad in my local newspaper trumpets “75% of all Americans don’t get enough Vitamin D” and offers to sell me Maximum Strength Vitamin D3, 5000 IU capsules to “promote bone, colon and breast health.” Meanwhile, the Institute of Medicine (IOM) tells me that “the majority of Americans and Canadians are receiving adequate amounts of … vitamin D” and that no one should take more than 4000 IU a day. Apparently Walmart and the IOM aren’t talking to each other.
The media have been giving the impression that vitamin D is a new wonder drug. They have told us that we aren’t getting enough sunlight, that a large percentage of us suffer from vitamin D deficiency, and that low levels of vitamin D are associated with cancer, multiple sclerosis, peripheral vascular disease, diabetes, rheumatoid arthritis, Parkinson’s and Alzheimer’s disease, and other conditions. Low levels of vitamin D have been linked to higher overall mortality (but so have high levels of vitamin D!). The anti-vaccine folks have been telling us (without any controlled studies) that vitamin D supplements are better than vaccines for preventing influenza. There’s no good evidence that raising vitamin D levels with supplements actually prevents any of these conditions, but many people think it should, and doctors have increasingly been measuring blood levels and prescribing high dose supplements. Is this just another passing fad like the enthusiasm for vitamin C, or are we belatedly recognizing a serious deficiency problem?
I’ve had a lot of inquiries about “is this information trustworthy?” and “how much vitamin D should I be taking?” I’ve been telling people that I didn’t know, that recent findings will soon result in new recommendations, and I’ve been eagerly awaiting the new guidelines. Now we have them, thanks to the IOM. They are not what most of us anticipated. Since so many doctors had been advocating higher levels to prevent things like cancer, I thought official recommended intake levels would go up; instead, they went down.