You’ve probably read the latest statistics on vitamin D deficiency. For example, more than 70 percent of the population of the United States is D deficient, and a lack of that key vitamin has been linked to everything from heart disease to cancer to impotence.
So many people are deficient because one of the only ways to get vitamin D is to get out in the sun—and winter sun doesn’t cut it. You need intense sunlight, the kind you get in summer. Now evidence point to a D deficiency as contributing to depression. That could stem from the fact that low D means a sluggish immune system. It can also be a direct result of low testosterone, as vitamin D plays a vital role in optimal hormone production.
If you don’t get out in the sun often, take vitamin D supplements, at least 2,000 international units per day. And always supplement in the winter.