Last week, an article was published on outsideonline.com titled “Is Sunscreen the New Margarine,” putting forth an opinion that sunscreen is basically bad for you because it blocks vitamin D. The author focuses heavily on the work of one researcher, Richard Weller, a dermatologist at the University of Edinburgh and Chief Medical Officer of sunscreen company RelaxSol (not disclosed in the article), and the work of Pelle Lindqvist, a senior research fellow in Ob/gyn at the Karolinska Institute. But would I as a dermatologist advise you to skip the sunscreen because of these few isolated opinions?  TLDR: Heck no. Read on for why.

I went back to the data to explore this idea.I read the original paper (abstract above) published by Pelle Lindqvist in Journal of Internal Medicine in 2016. Researchers administered questionnaires to 29,518 women from 1990-1992 asking about sun exposure, alcohol consumption, smoking, marital status, education level, and number of births. These women were followed for 20 years and information about their health, development of diseases such as cancer and cardiovascular disease, and cause of death, were recorded. The researchers concluded that women with active sun exposure habits were at lower risk of heart disease and were less likely to die from non-cancer and non-heart disease causes than those who avoided sun. They even went so far as to say that avoidance of sun puts you at the same health risk as if you smoked!

My biggest issue with the study that calls all the results into question is that it did not control for several other important confounding factors in this study. Sun protective measures, for one! They measured sun exposure by asking about how often people sunbathe, use tanning beds, or go on vacation during the winter months, but they never asked if these women used sun protection in the form of hats or sunscreen. To me, this is a huge confounder because sure, these women may have gotten more sun, but they may have also been more careful about how they got the sun. Even worse, important risk factors for heart disease such as family history of heart disease, poor diet, lack of exercise, high blood pressure, obesity, diabetes, just to name a few, were NOT measured and were NOT controlled for in the study. So that off the bat is a huge red flag for me in terms of trusting the results of this study.

Weller, the other researcher quoted in the article, has not published his data yet in a peer reviewed journal. The author of the margarine article writes that Weller’s study tracked blood pressure in 340,000 individuals around the US adjusting for age and skin type. The preliminary finding? People in sunnier climates have lower blood pressure. I can’t analyze the study because it has not been published or verified yet, but I would need to know what other risk factors for high blood pressure the researchers controlled for. For example, people in sunnier climates may smoke less, or eat healthier, or exercise more, or have less stress. Any of those factors could influence development of blood pressure.

My other big gripe with the article is the idea that sunscreen blocks all UV radiation and thus vitamin D production. This is simply NOT true. First of all, sunscreen doesn’t block all UV radiation. A sunscreen of SPF 15 filters out ~93% of all incoming UVB rays, SPF 30 filters out 97%, and SPF 50 blocks ~98% (source: Skin cancer Foundation). Secondly, we know that people do not apply nearly enough sunscreen to get the full stated SPF benefits. All the studies determining SPF of a sunscreen are performed with subjects applying 2 mg/cm2, but researchers have found that in real life people apply around 0.39 to 1 mg/cm2! Not only do we not apply enough sunscreen on our skin, we also don’t apply it evenly all over the skin. A random sample of beachgoers found that people applied less than 10% of the recommended amount, and they rarely put sunscreen on their ears, feet, or back. There is no way that we are blocking ALL UV radiation from reaching our skin by any means.

Another extremely troubling statement in the article is the dismissal of skin cancers as serious and potentially life threatening diseases. I have seen firsthand basal cell carcinomas that have gnawed their way through a person’s ear, skull, and eye socket.  I have seen squamous cell carcinomas that metastasize to internal organs. I have seen patients undergo major surgeries, radiation, immunotherapy, and suffer through all the side effects of the medications and procedures.  And I’ve had patients die from melanoma. Think about this: ~86% of melanomas can be attributed to UV exposure from the sun. This is a PREVENTABLE CANCER. Even if those patients became Vitamin D deficient with sun avoidance, vitamin D supplementation through pills or diet changes would have been a lot easier to do than to deal with a melanoma.

Additionally, certain groups of people need stricter sun avoidance and diligent sunscreen use. There are skin conditions called photodermatoses which get much worse with excessive sun exposure, such as systemic lupus erythematosus (SLE), polymorphous light eruption, and rosacea, just to name a few. Patients on certain medications such as doxycycline (a common antibiotic used for acne) or Methotrexate are more photosensitive and risk getting burned more easily. Transplant patients are 100 times more likely to develop squamous cell skin cancer, twice as likely to develop melanoma, and the skin cancers are more aggressive and fatal. And patients with vitiligo or other depigmenting disorders are at higher risk for getting sunburned and developing skin cancer. It would be unsafe and downright dangerous to tell all of these patients that sunscreen is not important for their health.

One point that the article brings up is actually interesting, in my opinion, and that is the idea that sun protection should be individualized for each person’s skin color. People with more eumelanin in their skin, meaning they have more pigment, are more protected against UV radiation. This also means that they need longer UV exposure time in order to produce Vitamin D. All true facts. When I see darker skinned patients in my clinic, I don’t emphasize the daily use of SPF 30 sunscreen to prevent skin cancer because the chances of them developing melanoma are much smaller. However, what the article completely misses is that darker skin types are at much higher risk for pigmentary disorders, such as melasma, post inflammatory hyperpigmentation, and scarring, among others, which are exacerbated by sun exposure. Sunscreen use and diligent sun protection are key to preventing those pigmentary disorders from getting worse.

Bottom line: As a board certified dermatologist, I advocate for sun protection daily, especially if you are at high risk for developing skin cancer, BUT I am by NO MEANS telling you to avoid the sun at all costs. I tell all my patients every day: it is simply unrealistic to completely avoid the sun. But enjoy the sun in moderation, with sunscreen and protective gear, and please don’t get sunburned or use tanning booths, because we know that both increase your risk of developing melanoma. This is the same stance taken by the American Academy of Dermatology, whose excellent response to this article can be found here. To liken sunscreen to known risk factors for your heart like smoking and margarine, which turned out to contain trans fats that are bad for cardiovascular health, is absurd, and entirely dangerous.

Sources:

Petersen B, Wulf HC. Application of sunscreen — theory and reality. Photodermatol Photoimmunol Photomed. 2014 Apr-Jun;30(2-3):96-101. doi: 10.1111/phpp.12099. Epub 2014 Jan 6.

Lademann J, Schanzer S, Richter H, et al. Sunscreen application at the beach. J Cosmet Dermatol. 2004 Apr;3(2):62-8.

 https://www.skincancer.org/prevention/sun-protection/sunscreen/sunscreens-explained

https://www.skincancer.org/skin-cancer-information/skin-cancer-facts#general

https://www.skincancer.org/prevention/are-you-at-risk/transplants