Could a little sunshine melt away the pounds? Well, I suppose if the sun is hot enough it would, or…making a little extra Vitamin D might be less painful. At any rate, I found a really cool “quiz” that sums up the Vitamin D and obesity research in a fun way.
The studies on Vitamin D, sunlight, and obesity tend to suggest that moving to from a high to low altitude, thus decreasing sun exposure, increases body fat. There are other factors that could lead to increased body fat besides Vitamin D levels in these cases. However, other studies controlled for these other factors, and found that when populations that dress modestly (e.g. Saudi Arabian women) moved altitudes, there was no weight gain or loss. This suggests that Vitamin D could be the weight-loss/weight-gain factor here.
Studies show that obese individuals have lower circulating levels of Vitamin D and Calcidiol than normal-weighted individuals. In what could be an exciting finding, some studies have shown a linear relationship between body fat and blood calcidiol (that is, as the calcidiol in the blood drops, body fat goes up, and vice versa). Of course, more research is needed before it is clearly known what role Vitamin D plays in obesity, but it is pretty exciting!
Anecdotally, upping my Vitamin D intake to 1000-2000 IU/day coincided with my “turning the corner” in my effort to gain muscle, and lose fat (even when eating more than I should have). I know that correlation does not imply causation, which is why I am only providing this as an anecdote. I also tend to do a lot of the right things related to my health, so it would be unwise to give Vitamin D all the credit.
Vitamin D is cheap. It is available. It is pretty much non-toxic. If there is one supplement we should be taking (especially in the winter) it is Vitamin D. I take quite a few supplements, but if I was limited to one, it would be Vitamin D (it is funny…but 10 years ago it probably would have been dead last on my list…but recent research has changed all that).
Image taken by me in Mt. Airy, North Carolina, in 2007.