A Washington, D.C., consumer group is reminding consumers that mis-use (over-use) of chemical sunscreen will lead to vitamin D deficiency and may actually contribute to an increase in skin cancer rates.

The non-profit Environmental Working Group — perhaps the world’s leading advocate of better product safety testing for chemical sunscreen products — has posted “Sunscreens Exposed: 9 Surprising Truths on its web site. Included in that list:

1. There’s no consensus on whether sunscreens prevent skin cancer.

The Food and Drug Administration’s 2007 draft sunscreen safety regulations say: “FDA is not aware of data demonstrating that sunscreen use alone helps prevent skin cancer” (FDA 2007). The International Agency for Research on Cancer agrees. IARC recommends clothing, hats and shade as primary barriers to UV radiation and writes that “sunscreens should not be the first choice for skin cancer prevention and should not be used as the sole agent for protection against the sun” (IARC 2001a). Read more.

2. There’s some evidence that sunscreens might increase the risk of the deadliest form of skin cancer for some people.

Some researchers have detected an increased risk of melanoma among sunscreen users. No one knows the cause, but scientists speculate that sunscreen users stay out in the sun longer and absorb more radiation overall, or that free radicals released as sunscreen chemicals break down in sunlight may play a role. One other hunch: Inferior sunscreens with poor UVA protection that have dominated the market for 30 years may have led to this surprising outcome. All major public health agencies still advise using sunscreens, but they also stress the importance of shade, clothing and timing. Read more.

3. There are more high SPF products than ever before, but no proof that they’re better.

In 2007 the FDA published draft regulations that would prohibit companies from labeling sunscreens with an SPF (sun protection factor) higher than “SPF 50+.” The agency wrote that higher values were “inherently misleading,” given that “there is no assurance that the specific values themselves are in fact truthful…” (FDA 2007). Scientists are also worried that high-SPF products may tempt people to stay in the sun too long, suppressing sunburns (a late, key warning of overexposure) while upping the risks of other kinds of skin damage.

Flaunting FDA’s proposed regulation, companies substantially increased their high-SPF offerings in 2010. Nearly one in six products now lists SPF values higher than 50, compared to only one in eight the year before, according to EWG’s analysis of nearly 500 beach and sport sunscreens. Neutrogena, with six products labeled “SPF 100,” and Banana Boat, with four, stand out among the offenders. Read more.

4. Too little sun might be harmful, reducing the body’s vitamin D levels.

Adding to the confusion is the fact that sunshine serves a critical function in the body that sunscreen appears to inhibit — production of vitamin D. The main source of vitamin D in the body is sunshine, and the compound is enormously important to health – it strengthens bones and the immune system, reduces the risk of various cancers (including breast, colon, kidney, and ovarian cancers) and regulates at least 1,000 different genes governing virtually every tissue in the body. (Mead 2008) Over the last two decades, vitamin D levels in the U.S. population have been decreasing steadily, creating a “growing epidemic of vitamin D insufficiency” (Ginde 2009a). Seven of every 10 U.S. children now have low levels. Those most likely to be deficient include children who are obese or who spend more than four hours daily in front of the TV, computer or video games (Kumar 2009).

Experts disagree on the solution. The American Medical Association has recommended 10 minutes of direct sun (without sunscreen) several times a week (AMA 2008), while the American Academy of Dermatology holds that “there is no scientifically validated, safe threshold level of UV exposure from the sun that allows for maximal vitamin D synthesis without increasing skin cancer risk” (AAD 2009). Vitamin D supplements are the alternative, but there is debate over the proper amount. The Institute of Medicine has launched new research to reassess the current guidelines. In the meantime, your doctor can test your vitamin D levels and give advice on sunshine versus supplements. Read more.

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