O’Connor’s piece was in the recurring Really? series (a Science Times investigation into bits of conventional wisdom in health-related areas) entitled The Claim: Sunscreen Prevents Vitamin D Absorbtion. The Facts . However, it most definitely did not have all of the facts since it presented only a single point of view in an area where expert opinion differs. And, although it is well documented that a liberal bias exists among journalists, people may not realize that bias may also extend to medical and scientific reportage. In this instance, O'Connor leans towards the orthodox dermatologic point of view (i.e., the cancer-phobic "avoid sunlight at all costs") as put forth by his expert, Henry Lim, MD a well-respected dermatologist from the Henry Ford Hospital in Detroit. So what do O'Connor and Lim say? Well, even if sunscreens do impede vitamin D production, it is negligible; and it is the fear of sun exposure (and, though unstated here, skin cancer) that is the key here.
However, while Dr. Lim is an expert in diseases of the skin, for matters related to vitamin D, I would rather hear what an expert on vitamin D has to say. (This is analogous to asking someone who rebuilds transmissions a question about a car's electrical system; they might know a bit about it since it relates to automobiles, but a better answer would undoubtedly come from someone who rebuilds electrical systems).
For vitamin D, I turn to Michael Holick, MD, PhD, who was asked to write a review on vitamin D deficiency for The New England Journal of Medicine (without a subscription you cannot get the full text of this 2007 article that I linked to within this sentence). There are few things in medicine that would more clearly identify a world-class expert than having been asked to write on a particular topic by the New England Journal of Medicine.
So, what does Dr. Holick have to say about vitamin D, the sun, deficiency and possible problems associated with insufficient D? Let's start with this quote:
According to several studies, 40 to 100% of U.S. and European elderly men and women still living in the community (not in nursing homes) are deficient in vitamin D.
But, is this important? Again, from Dr. Holick's article:
Of great interest is the role it [vitamin D] can play in decreasing the risk of many chronic illnesses, including common cancers, autoimmune diseases, infectious diseases, and cardiovascular diseases.
Hmmm...so widespread deficiency may have a role in certain common diseases. What is interesting to me in terms of The Times article is that the author did not discuss anything at all about this well-known common deficiency of vitamin D (that in some cases, may be related to sunscreen use), much less the possible public health impact of this phenomena.
Here is what Holick has to say about sun and vitamin D (D3 denotes animal-derived D and D2 plant-derived):
Sensible sun exposure can provide an adequate amount of vitamin D3, which is stored in body fat and released during the winter, when vitamin D3 cannot be produced. Exposure of arms and legs for 5 to 30 minutes (depending on time of day, season, latitude, and skin pigmentation) between the hours of 10 a.m. and 3 p.m. twice a week is often adequate.
So, before coating yourself with SPF 45 give yourself a few minutes of pure sun (and SPF 8 cuts vitamin D production in the skin by 95%).
One other point: I had thought that the author of The Times article, Anahad O'Connor might have been very sensitized to the problems of skin cancer and sun exposure since s/he was likely a freckle-faced, light-skinned individual of Celtic origins. However, I learned Mr. O'Connor is African American and thus might have been a bit more sensitive to the more widespread vitamin D deficiency in the African American community and the possible consequences of this.
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