Pigments in the skin help protect against damaging UV rays which can skin aging and damage DNA, resulting in cancer. People with lighter skin are able to synthesize vitamin D from the sun more easily, but are more susceptible to sunburns and cancers. There must be a balance between sun exposure for vitamin D and protection from the harm that comes with overexposure. While protective clothing is great, use of sunscreen is also recommended to protect skin from UV light.
Recently, a story appeared on RealFarmacy.com (RF) with the title “Scientists Blow The Lid on Cancer & Sunscreen Myth.” Except, of course, they really didn’t. The article argues against a great deal of conventional wisdom regarding sunscreens, including a number of false claims based on cherry-picked data. Here are some refutations to the biggest points made in the article:
Claim: “A study shows that women who limit Sun exposure are twice as likely to die from causes related to vitamin D deficiency.”
The article references a study that tracked nearly 30,000 Swedish women for 20 years and monitored sunbathing habits. The data showed that women who avoided sun were twice as likely to die as women who got more sunlight, but there were only two causes of death tracked: melanoma or “all-cause mortality” which is a catch-all.
However, the paper’s authors do not claim the lack of sun exposure is a cause for those deaths. It does, however, caution that people living in areas with decreased solar intensity should not limit their exposure based on recommendations for those living in areas where solar intensity is much higher.
Claim: “There is no evidence that sunburns cause melanoma, and people who use sunscreen are MORE likely to get melanoma than those that don’t.”
There are four basic varieties of melanoma, and there are genetic risk factors that make a person more susceptible to developing a form, and children who get more than five sunburns are more likely to develop melanoma later in life. There have been studies to implicate UVA and UVB rays for certain kinds of melanoma, but not all of them. UVB rays are also the main cause of sunburn, which is likely the link sunburns and melanoma. RF refers to claims in papers written at least a decade ago, and there has been a great deal of research done since then.
The claim that more people who use sunscreen develop melanoma is based on a study that tracked sun exposure and sunscreen use in nearly 1500 people over a span of two years. The results did show that those who used sunscreen were more likely to develop melanoma, but there was a massive caveat left out of RF’s article. The median sun protection factor (SPF) was 6 (the CDC recommends SPF 15 or higher) and those who used sunscreen the most spent considerably more time in the sun than those who rarely use sunscreen.
RF’s implication that sunscreen is causing the melanoma is dead wrong; the paper itself states “sunscreen use, by permitting more time sunbathing, is associated with melanoma occurrence,” particularly when using sunscreen with a low SPF that isn’t as protective.
Claim: “Eliminating exposure to sunlight has created epidemic vitamin D deficiencies.”
Vitamin D deficiencies have solid links to diseases affecting bone density such as rickets and osteoporosis. There is also some evidence that it could also affect blood pressure, irritable bowel disease, heart disease, and a variety of other cancers. Medical professionals actually do recommend about 20 minutes of exposure to sunlight each day in order to synthesize vitamin D, though that time is somewhat arbitrary, based on the solar intensity in different locations and the individuals skin type. Use of sunscreen does block the necessary UV rays, but there’s a large difference in soaking up the sun for a few minutes for your health and heading out for a day at the beach without using sunscreen. As always, everything in moderation.
Vitamin D can also be obtained through food sources including fortified milk, certain edible mushrooms, fish, and eggs.
Claim: “Sunscreens contain endocrine disrupting chemicals (EDCs) that stay in the body and can cause cancer and harm the environment.”
A common ingredient in sunscreens is oxybenzone, which protects against wide range of UVA and UVB rays. Some believe that when the sunscreen is absorbed by the skin, oxybenzone acts like estrogen in the body and could increase the risk of breast cancer. However, there haven’t been any studies to show that this chemical acts like estrogen in a significant way or causes cancer, even when given at doses much higher than normal.
RF does cite that testing by the CDC revealed that oxybenzone exists in the blood stream in up to 97% of Americans, it neglected to mention that it exists in trace amounts and has not shown to cause any negative health effects.
The article also states that EDCs negatively affect marine life. While there have been UV-blocking chemicals detected in fish, there was no indication they were harming the animals at all. While EDCs entering the water are a point of concern, sunscreen isn’t regarded to be nearly as problematic as birth control. However, there are also many quality sunscreens on the market that do not use these chemicals and still help protect against UV rays and cancer.
[Header image “Louis” by Bryan via flickr, used in accordance with CC BY-ND 2.0]