Ah, the power of D. Experts have long known that vitamin D plays an important role in bone health, preventing osteoporosis, gum disease and tooth loss. It may also protect against breast, ovarian, prostate and colon cancer.

So it’s no surprise that a lack of D can be a problem. A study published in the Journal of the National Medical Association found that D deficiency is linked to the formation of hypertrophic scars and keloids, common problems among African Americans. In addition, researchers are learning that a shortage increases risk for high blood pressure, diabetes and rickets (insufficient bone development in children).

Americans in general don’t get enough, but black people in particular need more. A study published in 2003 by the Centers for Disease Control found that nearly half of childbearing black women had insufficient amounts. So how can you get your D on? Spend at least 10 to 15 minutes in the sun twice a week, says Wilma Wooten, MD. Ultraviolet (UV) rays trigger the body to manufacture vitamin D, and people get 90% of the D they need from sunlight. African Americans may be getting less because “darker-pigmented skin converts sunrays to vitamin D less efficiently,” says Wooten. Those short winter days spent indoors don’t help either.

If you’re in the sun for more than 15 minutes, slap on some sunscreen (SPFs 8 and higher will protect your skin but also block D-producing UV rays). The next time you ditch the office to catch some sun, you can say it’s for your health!