"I need my vitamin D!" is one of the most common rationalizations women give for tanning. And it's true, the sun is a good source of the vitamin. But that may only work up to a point, according to a new study finding that the tanner you are, the less vitamin D your skin absorbs from sunlight.
Vitamin D has been touted as a miracle mineral in recent years thanks to a ton of studies that show that it strengthens your immune system, protects your bones, fights cancer, decreases heart disease, boosts athletic performance, reduces depression, and even helps you lose weight. Making sure you get enough D is one of the best things you can do for your health—and the easiest way to get it is shining right outside your window.
But according to researchers from Brazil, a country known for its love of sun-kissed golden skin (hi, Giselle!), the vitamin D-tanning connection is complicated. Here's how it works: When you go outside without sunscreen, UVB rays from the sun cause a reaction in your skin allowing your skin cells to manufacture vitamin D. Light-skinned people need just ten minutes a day to get their daily quota while people with darker skin need 15-30 minutes per day, according to the Vitamin D Council. (Still want to look tan? Find The Best Self-Tanner to Suit Your Fit Lifestyle.)
And therein lies the problem. Darker skin naturally absorbs fewer UV-B rays, which leads to less vitamin D. And the longer you're in the sun, the darker your skin gets. So the more tan you are, the less vitamin D you get from being outside.
Thanks to their tanned skin, over 70 percent of the people in the study were deficient in vitamin D—and that's in one of the sunniest countries in the world! The natural solution might seem to simply get more sun then. Unfortunately, as time unprotected in the sun increases, so does your risk of skin cancer—the number one cancer killer of people under 40 years old. (Eek! People Are Still Tanning Despite Rising Melanoma Rates.)
The answer, like with many health issues, is in moderation, say the researchers. Get enough sun to get your daily quota—and then cover up with sunblock and/or UV-protective clothing.