Sunscreen vs Vitamin D
The Claim: Sunscreen Prevents Vitamin D Production (NY Times), [and] Dermatologists routinely talk of the need to wear sunscreen. But the body needs sunlight to produce vitamin D, a crucial nutrient.
So is it possible that wearing sunscreen might interfere with the synthesis of vitamin D? Yes. Studies have found that by blocking ultraviolet rays, sunscreen limits the vitamin D we produce. But the question is to what extent. That is in part because most people typically do not apply enough sunscreen to get its full effects, which in turn allows some sunlight through, said Dr. Henry Lim, chairman of dermatology at the Henry Ford Hospital in Detroit and a spokesman for the American Academy of Dermatology.