Tuesday, 24 March 2009

Screening Out Vitamin D

The claim: Sunscreen prevents vitamin D production.

The facts: Dermatologists routinely talk of the need to wear sunscreen. However 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.
              A few studies have concluded that the effect is significant – a reduction as great as tenfold. However, more recent, randomised studies that followed people for months - and in some cases years – suggest that the effect is negligible. While sunscreen does hamper vitamin D production, these studies said, it is not enough to cause a deficiency.
              That is 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.
              Also, according to the National Institutes of Health, it does not take much sunlight to produce adequate amounts of vitamin D: Perhaps as little as 30 minutes of daytime exposure (without sunscreen) twice a week.
              Dr Lim added that rather than cutting back on sunscreen , people concerned about vitamin D should consume more foods rich in vitamin D, like salmon, milk and fortified orange juice.

The bottom Line: Sunscreen can reduce vitamin D Production but probably not enough to have a significant effect. 

- The New York Times 

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