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You may have noticed that we've always preached the merits of sunscreen (and shade). And for good reason: Sun exposure has been shownto cause skin cancer as well as wrinkles, sagging, and dark spots. But ultraviolet rays aren't all bad—they also prompt the skin to manufacture vitamin D, which has made headlines recently for its potential health benefits; new research links it to everything from stronger bones to a more robust immune system to reduced cancer risk. So we wondered whether religiously wearing sunscreen means we're cheating ourselves of some of the advantages of the vitamin.
The short answer: not necessarily. Despite the mounting evidence that vitamin D is crucial to good health, we have yet to find a dermatologist who condones any amount of unprotected time in the sun. "As someone who sees skin cancers daily, it's just not possible for me to recommend intentional sun exposure," says Marsha Gordon, MD, professor of dermatology at the Mount Sinai School of Medicine. "And in any case, no matter how careful we are, we all get some unintentional sun. Sunscreens aren't perfect, nor is the way we apply them."
While milk and many cereals are fortified with vitamin D, it occurs naturally in very few foods (mostly fatty fishes like salmon and tuna, as well as red meat). To compensate for the shortfall, supplements are necessary, says Anthony Norman, PhD, a professor emeritus of biochemistry and biomedical sciences at the University of California, Riverside, who has studied the vitamin for several decades. Choose supplements containing vitamin D3, which may be more effective than D2, and consider going above the Institute of Medicine's current vitamin D recommendations of 200 IU for people 50 and under, 400 IU for people 51 to 70, and 600 IU for people over 70. Many doctors believe these numbers are far too low, especially for people with any of the prime risk factors for vitamin D deficiency: age, obesity, lack of sun exposure, and darker skin. Norman recommends that everyone request a vitamin D test when they have blood drawn at their yearly physical, and supplement accordingly— he takes a 2,000 IU supplement daily (still far from the 10,000 IU considered the maximum safe daily intake by many experts). The Institute of Medicine's official vitamin D recommendations could change as early as next year—the group recently put together a panel to reevaluate its guidelines.