Is sunscreen harmful?

Recently the Environmental Working Group (EWG) released a report on sunscreen recommending only 39 of 500 sunscreens investigated. The report has been picked up by media outlets and now sunscreen is being touted as cancer-causing and hormone-disrupting. The report is not fraudulent, but it is somewhat specious, inflammatory, and alarmist. I’ve researched some of the claims and there is no reason to run screaming from sunscreen, as we’ll see.

One of EWG’s concerns is that many sunscreens lack UVA protection. This was absolutely true at one time, but is quickly changing. Many sunscreens are now “broad spectrum” or “double barrier,” protecting against UVA and UVB radiation.

Ultraviolet radiation comes in UVB and UVA forms. UVB radiation is that type that gives you sunburns; UVA radiation is the type that penetrates deeper into the skin and causes breakdown and more permanent damage. Both UVA and UVB rays are known to cause cancer, so it is best to purchase sunscreens (and sunglasses) that protect against both forms of radiation.

Another issue raised by the EWG report is that SPF numbers on sunscreens are climbing higher and higher, but there is little proof that such products are necessarily better. Again, this is true.

The Sun Protection Factor (SPF) on sunscreen labels refers to how well the product protects against sunburn (UVB). For example, without any sunscreen at all it may take you 10 minutes to burn in the sun, but using SPF 15 sunscreen would extend that time from 10 minutes to 150 minutes.

There are a few important things to keep in mind. First, because SPF measures the amount of time it takes to burn, it is only a measure of UVB protection – not UVA protection. Second, as noted in this document from the U.S. Environmental Protection Agency, above SPF 15 there are not great differences in protection. SPF 15 protects against about 93% of UVB radiation and SPF 30 protects against 97%. It’s very gradual from there on up.

Therefore, more important than the SPF number are the amount of sunscreen applied and the frequency of application. SPF numbers are typically based on a recommended application of 30mL (about 2 tablespoons) for the entire body. Most people apply less than this. Also, sunscreen should be re-applied every two hours and always after swimming. If the correct amount of sunscreen and frequency of application are observed, it makes little difference whether you use SPF 30 or SPF 60.

Although the case is not 100% closed on the link between sun exposure and cancer, there is plenty of scientific evidence of a link between sun exposure and basal cell carcinoma/squamous cell carcinoma (the common but rarely fatal, non-melanoma cancers that cause ‘scabs’ that can be removed). Melanoma is much more rare, but frequently fatal. The direct link between sun exposure and melanoma is not as clear as it is with carcinoma, but this doesn’t mean that intentionally baking in the sun or in a tanning bed is a good idea.

The EWG report claims that there is “no consensus on whether sunscreens prevent skin cancer.” This is somewhat true. The research is not 100% clear on a link between sunscreen and protection against skin cancer, but it is fairly favourable so far; generally scientists agree that sunscreen can protect against cancer if, as stated earlier, it is applied in the amounts and with the frequency recommended. A quick slather in the morning may actually do more harm than good, providing people with a false sense of protection against the sun, causing them to have more exposure to dangerous UV radiation. (High SPF numbers may also provide this false sense of protection.)

Although I have been using the term “sunscreen” throughout this article, there actually is a difference between sunblock and sunscreen.

Sunblock, such as titanium dioxide and zinc oxide, is more effective than sunscreen and is opaque (like the white stuff lifeguards often wear on their noses). Particulate matter in sunblock reflects and scatters the UV rays, physically blocking the sun. Sunblocks protect against UVA and UVB radiation, are safe, and are photostable (photostability refers to whether/how quickly the ingredients are broken down when irradiated). Vanity is essentially what prevents people from using such sunblocks – because it is opaque people don’t want to spend a day at the beach with a white coating all over their body. Although there are titanium and zinc products available now that are nearly transparent.

Sunscreen filters and absorbs UV radiation, converting it to heat. Although more and more sunscreens are being made with UVA and UVB protection (“broad spectrum” or “double barrier”), the ingredients in sunscreen are broken down more quickly when irradiated (they are less photostable). Not to belabour the point, but because most people will choose sunscreen over sunblock for aesthetic reasons, it is vital to apply it in the quantity and with the frequency recommended.

The EWG report claims that there is “some evidence” linking sunscreen usage with an increased risk of melanoma. This “some” is spotty at best and can more reasonably be explained by the false protection issue discussed above. People who use sunscreen likely spend more time in the sun because they feel protected, but most people are using sunscreen incorrectly (not enough, not often enough) and so do suffer greater effects of sun exposure. This is not a direct link to sunscreen, but to incorrect usage of sunscreen.

Another concern highlighted in the EWG report is that sunscreen will reduce vitamin D absorption. Vitamin D from the sun is very important, so if this is a concern for you (even though there is a lack of evidence for it), there are vitamin D supplements, but please – if you think you need to supplement your vitamin D intake, go to your doctor and get tested first, then get her recommendation for a product and a dosage. Don’t just buy some vitamin D pills from your local drug store and start popping them like candy, as most people do with vitamin supplements. You can overdose on vitamins; they’re not innocuous.

The EWG report cites the ingredient retinyl palmitate (a form of vitamin A) as a primary concern because “available data from an FDA study indicate that…when applied to the skin in the presence of sunlight, [it] may speed the development of skin tumors and lesions.” The problem is that the FDA study of retinyl palmitate in mice is both inconclusive and incomplete (it will be completed and peer-reviewed in the next year or so). Reason suggests that in light of the lack of evidence, it would be more dangerous to avoid the use of sunscreen than to use sunscreen containing retinyl palmitate.

Retinyl palmitate is a very common “anti-aging” ingredient and is found in most skin care and beauty products. It is not, however, a necessary ingredient for sunscreen’s effectiveness. If it is a concern for you, then choose a sunscreen that does not contain retinyl palmitate. Problem solved.

The EWG report also cites the ingredient oxybenzone as a potential hormone disruptor. (More information on hormone disruptors exists than I can synthesize here, so I would suggest doing your own research if you are interested. Check out science and medical sites/books rather than “health” sites/books). Oxybenzone is an ingredient in some sunscreens and, again, most skin care and beauty products. It is also ubiquitous in our environment. Studies are inconclusive as to the health effects associated with oxybenzone, stating such effects as unknown and requiring more research. As with retinyl palmitate, good sense says that you should not avoid sunscreen due to the presence of oxybenzone because evidence for negative health effects is so lacking, but you can certainly choose a product that does not contain it. Again, problem solved.

The Environmental Working Group tends to be overly cautious and even at times alarmist; they discount far too many ingredients as harmful, hazardous, or risky based on false or inconclusive data. Running around like a Chicken Little knock-off suggesting that sunscreen will give you cancer is not productive. As I said, the EWG sunscreen report is not fraudulent, but it (and the media reports on it) does instill a little too much fear in the general public.

As any brochure on sun exposure will tell you, avoiding the sun and wearing protective clothing is the best way to protect against harmful UVA and UBV radiation. Your next best bet is sunblock (titanium dioxide and zinc oxide). If the aesthetic of that doesn’t appeal to you, then a broad spectrum/double-barrier (UVA/UVB) sunscreen will offer adequate protection if you wear enough of it and re-apply it often.

Check out the EWG report for some good sunscreen/sunblock recommendations, but if you’re going to read the whole report, take it with a grain of salt keeping in mind the things discussed here. And, as always, do your own (good) research.

Advertisements

Oprah gets called out for her quackery

Here is a really good article from NEWSWEEK calling out Oprah Winfrey and her parade of pseudoscientific guests for promoting quackery. The article doesn’t go too deeply into the science of things, so I just want to make a few comments.

The first one is brief. Regarding the woman who adopted the strategy of “The Secret” (I can hardly type that without gagging) and rid herself of breast cancer: There is such a thing as spontaneous remission. It is rare (estimates range from 1 in 60,000 to 1 in 100,000), but it is medically documented and happens often enough considering cancer rates. For more on spontaneous remission, read this.

Now, a more lengthy comment on vaccinations and the anti-vaccination movement. There are no discernible links between autism and vaccinations. Nearly 20 scientific, reproducible studies have been conducted throughout the world to date, and the indisputable conclusion is that there is no association between autism and vaccines. Study after study after study, including the U.S. Autism Omnibus proceedings, prove that there is no link between vaccines and autism.

The major battle cry of anti-vaccinationists was that thimerosal (the preservative used to prolong the shelf life of vaccines) was the cause of autism. In 1999, the U.S. Food and Drug Administration investigated thimerosal in vaccines and found no evidence that it causes any harm. However, they ordered the removal of thimerosal from childhood vaccines as a precautionary measure (in essence to placate the hysterical). Ten years after thimerosal was removed from vaccines, autism rates have continued to rise.

One “study” and the “doctor” who conducted it, Dr. Wakefield, connected the MMR (measles, mumps, rubella) vaccine with autism. Despite not one scientist being able to replicate the results of this study for years, the anti-vaccinationists have clung to it as all the proof they needed.

Except that Dr. Wakefield’s findings have now been shown to be completely bogus:

“…there has emerged potential explanations of how Wakefield was able to obtain the results he did. This evidence, combined with unprecedented access to medical records, a mass of confidential documents and cooperation from parents during an investigation by this newspaper, has shown the selective reporting and changes to findings that allowed a link between MMR and autism to be asserted.”

One study—a fabricated study—has caused people to hysterically decry vaccinations, many refusing to have their children vaccinated. The result? No more herd immunity, for one. Herd immunity occurs when enough of the population is vaccinated that protection is afforded to the unprotected (and in some cases especially susceptible, perhaps because of illness or poor immune systems). The mechanism is simple—infection can’t easily pass from person to person when the majority of the population is protected. The chain is broken. Now in the UK vaccination rates have sunk so low that herd immunity is not maintained. And in North America, we’re getting close to that.

The result is that children will die needlessly of measles, mumps, and rubella. We think of these diseases as antiquated, but that’s only because in the past immunizations and herd immunity has protected children from them. Now that some parents are listening to the anti-vaccinationist wackos and refusing to vaccinate their children, these diseases are on the rise. And they can be deadly.

It is true that autism rates have been rising, but the cause of this rise is a controversial subject. Either true autism rates are rising, or increased surveillance and a wider definition of “autism” has made it appear as though the rates are rising. The second hypothesis is more strongly supported by available evidence. Simply, it is that more cases are being diagnosed, not that more cases are occurring.

So Jenny McCarthy, the head cheerleader of the anti-vaccination movement (who has recently recruited her boyfriend Jim Carrey to the battle), and all of the other credulous folks who believe the propaganda and pseudoscience, are actually endangering your children by not having theirs vaccinated.

One wonders why they aren’t concerned with the real causes of autism, focusing their energy, time, and money on scientific research that may one day provide an answer.