Many publications have reported on vitamin D deficiency. Some even speak of it in terms of an epidemic. However, as with so much in nutrition, especially supplements, controversy abounds. In the end, it probably boils down to the usual good advice.
How Much Vitamin D?
First, what counts as enough vitamin D? A comittee of the Institute of Medicine concluded that a blood serum level of 20 ng/mL of vitamin D is adequate for 97.5% of the population. Levels above 50 ng/mL may be too much.1 However, if you research further you can find recommendations as broad as 20 ng/mL at the low end to as high as 100 ng/mL on the high end.2
The large range comes from the fact that research has failed to yield clear cut answers about appropriate levels of vitamin D in the body. William Dietz, M.D., Ph.D., an expert on obesity, and director of the Sumner M. Redstone Global Center for Prevention and Wellness at George Washington University in Washington, D.C., explains: “The topic is controversial and the studies are contradictory. All sorts of claims about consequences have not been substantiated over time.” Indeed, for every study discussing vitamin D levels and its effects, you will find another making an opposite case. As of yet, we have been unable to sift through and come to a definitive conclusion.
Will Raising Vitamin D Make An Improvement?
According to Dr. Dietz, there are known consequences of extreme vitamin D deficiency, such as rickets, which has been associated with strict vegetarian diets. With that in mind, 20 ng/mL really is a good marker for the lower limit. But beyond that, there is very little that we can say. Is 25 ng/mL, for example, better than 20? Is aiming for the high end of the range better than hovering at the lower end? “I don’t think we know the answer to that,” Dietz says. “We know there are consequences of extreme vitamin D deficiency but there are also risks associated with being too high. When you talk about borderline levels, there just doesn’t seem to be a measurable outcome which can help demonstrate improvement.”
Diet And Exercise Is Always A Good Bet
In short, other than knowing that extreme deficiency will cause problems, there isn’t a lot we can say for sure about vitamin D levels. In the face of uncertainty, one of the best things you can do for yourself is ensure that you eat well and stay active. A healthy diet and regular physical activity – in this case, outdoor physical activity – can go a long way to covering your health bases. Foods like fatty fish, egg yolks, and fortified dairy are good sources of vitamin D. Regular exposure to the sun (without getting burned) will spur your body to synthesize its own.
Unsurprisingly, eating well, exercising, and spending some time outdoors is still the best formula we know of for staying healthy. As always though, know that when in doubt, the place to turn is to your doctor. Be informed, then have a discussion.