Why Vitamin D Isn't Snake Oil
Vitamin D seems to prevent many of our ills. Some studies show that taking large doses of it will treat just about everything from building strong bones to protecting us from strokes and heart failure to reducing our risk of cancer and on to helping us regulate our immune system and control inflammation, our blood pressure, and even our blood glucose. Higher levels of vitamin D is associated with reduced risks for multiple sclerosis, rheumatoid arthritis, and type 1 diabetes.
Reports of the value of vitamin D for preventing even more conditions continue to appear regularly. Low levels of vitamin D are associated with poor lung function among children with asthma, leading them to use more medication to treat it, as the Journal of Allergy and Clinical Immunology recently reported. Vitamin D might treat or prevent allergy to a common mold that can complicate asthma and frequently affects patients with cystic fibrosis, according to a study that the Journal of Clinical Investigation published a few days ago.
As I wrote here last year we nevertheless might have good reason to wonder if all the current hype over vitamin D is nothing more than a resurgence of snake oil claims.
How could just getting out into the sun more or taking just one inexpensive and tiny pill each day work such magic? It seems to be too good to be true. It doesn’t seem to pass the smell test.
Yet we already had a hint to the solution of this major nutritional puzzle when we learned that what we call “vitamin D” isn’t really a vitamin. When scientists discovered vitamin D in the 1920s and 1930s it seemed to work like a vitamin, so that’s what the called it.
“We have confirmed with our recent research that vitamin D isn’t a vitamin at all,” says Professor Trevor Marshall of the school of biological sciences and biotechnology at Murdoch University in Western Australia. It’s a hormone that is made by the body itself.”
And today the other shoe dropped. Several days ago the Wellcome Trust sent me under embargo the advance word on the latest study that journalists could print this evening. The Wellcome Trust is a global charity headquarters in Britain dedicated to improvements in human and animal health.
The main conclusion of this study goes a long way to explaining why vitamin D seems to work its magic throughout our bodies. The journal Genome Research will publish a study led by Sreeram Ramagopalan and Andreas Heger at the University of Oxford.
Using new DNA sequencing technology, they identified more than 200 genes that vitamin D directly influences and created a map of vitamin D receptor binding across the genome. Vitamin D attaches itself to DNA, thus influencing what proteins we make from our genetic code byactivating this receptor.
The researchers discovered 2,776 binding sites for the vitamin D receptor along the length of the genome. These were unusually concentrated near a number of genes associated with susceptibility to autoimmune conditions and to certain cancers. They also found that vitamin D had a significant effect on the activity of 229 genes including PTPN2, associated with Crohn’s disease and type 1 diabetes.
“Vitamin D status is potentially one of the most powerful selective pressures on the genome in relatively recent times,” says Professor George Ebers of the University of Oxford and one of the senior authors of the paper. “Our study appears to support this interpretation and it may be we have not had enough time to make all the adaptations we have needed to cope with our northern circumstances.”
Seldom does basic science like this make the headlines. But this research certainly warrants that. If vitamin D is snake oil, I’ll drink it.