Conventional wisdom says that you should always wear sunscreen or protective clothing and get your vitamin D from food and supplements, but science doesn't agree. "Exposure to sunlight has a lot of benefits above and beyond producing vitamin D," says Michael Holick, PhD, MD, professor at Boston University School of Medicine, author of The Vitamin D Solution, and arguably the world's leading expert on healthy sun exposure.
Holick has been researching the subject for more than 30 years, and discovered many sun facts that we now take for granted: that winter sun in northern climates doesn't lead to vitamin D production in the skin, for example. And surprisingly, that sun exposure generally reduces risk for all cancers except nondeadly, nonmelanoma skin cancer. People who are especially sun-sensitive or are genetically predisposed to melanoma are exceptions.
Unique Sun Benefits
Although Holick recommends taking 1,500-2,000 IU of vitamin D daily in supplement form, year-round, there are additional benefits only the sun can deliver. "Sunlight makes you feel better," he says, because it triggers production of beta-endorphins-natural feel-good chemicals-in the skin. And, sun-exposed skin makes nitric oxide, which relaxes blood vessels and may help reduce blood pressure.
What to Do
"I encourage sensible sun exposure," says Holick. That means: never get a sunburn; always protect your face; but do expose your arms, legs, abdomen, and/or back.
The optimal amount of sun you need depends upon your skin type, location, time of day, and season. To work out the details, Holick helped develop an app that uses your phone's GPS to calculate your optimum sun time anywhere in the world. Both free and paid versions are available from app stores and at dminder.ontometrics.com
Vitamin D Cat Fact
Unlike humans, cats can't make vitamin D in the sun, so they must get the nutrient from food. At the University of Edinburgh in Scotland, a study of 99 pet cats found that higher vitamin D levels in food helped the felines recover from virtually any type of illness. However, too much vitamin D can be toxic to cats, so stick to food-based sources of the vitamin.