It is well-established in the scientific literature that sunscreen — which blocks UVB and most UVA light — almost completely blocks vitamin D production. So this week’s article in The New York Times adding credibility to a poorly designed, poorly executed study alleging that sunscreen doesn’t block vitamin D production is surprising.

The Times got duped.

Studies have found that by blocking ultraviolet rays, sunscreen limits the vitamin D we produce. But the question is to what extent.

“A few studies have concluded that the effect is significant — a reduction as great as tenfold,” Times writer Anahad O’Connor wrote in a piece called, The Claim: Sunscreen Prevents Vitamin D Production. “But more recent, randomized 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 say, it is not enough to cause a deficiency.”

The explanation? “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. And 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.”

So in other words — sunscreen does block vitamin D, and if people used as much as dermatology leaders said we should be using, then it would block as much vitamin D production as has been reported.

“This is about Big Dermatology attempting to protect itself from massive potential liability,” Smart Tan Vice President Joseph Levy said. “Expect to see more studies like this attempting to spin the case that dermatology leaders’ advice has not caused vitamin D deficiency. It’s disappointing that a Science Writer from the times couldn’t see through this and couldn’t at least call the obvious question.”

Instead, the Times advised, “THE BOTTOM LINE: Sunscreen can reduce vitamin D production, but probably not enough to have a significant effect.”

“We know that sunscreen blocks vitamin D production,” Levy said. “What the Times should have said is what we have been saying all along: That sunscreen should only be used to prevent sunburn on occasions when sunburn is a possibility. But daily usage of sunscreen is not indicated and blocks vitamin D production in exchange for no benefit.”

To read The Time story click here.