Are We Wearing Too Much Sunscreen?

There seems to be a lot of chatter on social media platforms about whether or not we’re getting enough vitamin D. Being conscientious of one’s health is great, but this new obsession seems to be creating some backlash against using sunscreen for fear that if you apply it and have UPF rated clothing on you won’t naturally produce enough of the vitamin. Is this actually true or a scare tactic from online “influencers”? After seeing so many posts discouraging sunscreen application, I tucked into a lot of medical journals looking for supporting evidence for the correlation between lower vitamin D levels and SPF usage.

Vitamin D plays a vital role for building and maintaining bone health and supporting a strong immune system. Bones can only absorb calcium when vitamin D is present. According to the Mayo Clinic, 600 IU is the daily recommended amount for people 1 to 70 years old, and 800 IU for people over 70 years old. This nutrient isn’t naturally present in a lot of foods but salmon, tuna, mackerel, and egg yolks are decent natural sources. Products like milk, cereal, and orange juice can be fortified with it but read the labels to ensure that they actually are.

So, does sunscreen actually hinder a person’s ability to produce vitamin D? In certain instances, yes, but mostly no. Here’s what it boils down to. Several studies that did suggest sunscreen blocks vitamin D creation used “artificially generated ultraviolet radiation with output unlike that seen in terrestrial sunlight.” (Neale et al.) Using a really strong fake sun to manipulate the radiation to impractical levels, artificial light doesn’t consider environmental factors like ozone, distance of the sun from the earth, or contaminants that affect radiation amounts. In this unrealistic setting the amount of sunscreen needed to protect the skin from redness was enough to inhibit vitamin D production. In an artificial setting, yes, sunscreen reduces vitamin D production.

Another instance where vitamin D might be affected is people with extreme cases of photosensitivity disorders like xeroderma pigmentosum. In these rare cases, patients are required to take extreme measures to protect their skin. Copious amounts of high rated sunscreen along with hats and UPF clothing all while seeking shade are a daily necessity. These instances should not be considered the norm.

In studies that compared real life sun exposure scenarios (not lab generated artificial UVR), this is not the case. Human error is the great delineator. It’s the UVB, burning rays, that’s needed to synthesize vitamin D in the body. Broad spectrum sunscreen does protect against these but doesn’t block 100% of them no matter the label number. Most people using sunscreen for daily indirect exposure and general recreational use aren’t actually applying enough of the product to get the SPF that’s on the label, let alone block enough UV radiation to affect vitamin D synthesis. “An SPF 15 sunscreen filters out 93 percent of UVB rays, SPF 30 keeps out 97 percent, and SPF 50 filters out 98 percent. This leaves anywhere from 2 to 7 percent of solar UVB reaching your skin.” (Skin Cancer Foundation) One “dose” of sun exposure to 6% of the skin is equivalent to taking 100-600 IU of vitamin D. (Brummitte, et al.) In other words, you’re getting enough sun exposure to create the nutrient.

One consistent theme throughout these papers is that adverse effects from sun exposure, both short and long-term, are very well documented as are the protective benefits of sunscreen. A few other things to take into consideration when reading and analyzing papers about vitamin D production are what type of radiation/ light source is used, artificial vs. natural. If it is natural light, geographic latitude, season, and time of day all need to be considered. One often overlooked factor in many studies was how much baseline vitamin D a person had. The lower the baseline, the more it was affected by UV radiation exposure.

In a day-to-day scenario, the probability that people are wearing enough sunscreen, and reapplying it correctly to inhibit their vitamin D production, is fairly low. The evidence of the long-term consequences of not wearing sunscreen far exceeds the limited possibility of reduced personal vitamin D synthesis. Wear your sunscreen and continue to have good sun practices. If you’re still concerned with your vitamin D levels, have a discussion with your doctor about possibly adding a supplement.

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Chandra, Prakash, et al. “Treatment of Vitamin D Deficiency with UV Light in Patients with Malabsorption Syndromes: A Case Series.” Photodermatology, Photoimmunology & Photomedicine, vol. 23, no. 5, 2007, pp. 179–185, https://doi.org/10.1111/j.1600-0781.2007.00302.x.

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