Sunlight and Skin Health
Sunlight and Health
Human health has a complicated relationship with the sun. While the sun’s rays can have damaging effects on the skin and trigger premature skin aging, wrinkles, sunburns, and skin cancer, exposure to sunlight also has benefits for our overall health. We need sunlight to help us synthesize vitamin D, and there is evidence that sun exposure can improve serotonin levels and impact our mood.
Sunset in the Snake River Canyon near Twin Falls, Idaho
UV Radiation, Sun Damage, and Vitamin D
Ultraviolet (UV) rays from the sun damage our skin on a cellular level. There are two main types: UVA rays and UVB rays. UVA rays can trigger changes that cause premature aging and wrinkles because they penetrate deeply into the skin (and can go through clouds and windows). UVB rays cause sunburns but can be filtered by clouds and windows. Exposure to both types of UV rays can lead to skin cancers, including melanoma.
UVB rays, the same ones that cause sunburns and can lead to skin cancer, are needed to produce vitamin D, our “sunshine vitamin.” Vitamin D is necessary for bone health and immune system function (among other things). It is important to balance our need for vitamin D with preventing skin damage. Sun exposure adds up over time. The more time you spend in the sun without skin protection, the higher your risk of skin cancer. People living in sunny places have a higher risk because they’re exposed to sunlight more frequently.
Fortunately, according to the World Health Organization, just 5-15 minutes of casual sun exposure to hands, arms, and face (without sunscreen) two to three times per week is sufficient for vitamin D production. Additionally, while sunscreen absorbs most UVB rays, it doesn’t block them all, so wearing SPF-15 sunscreen still allows 7% of rays to penetrate the skin and help produce vitamin D. That doesn’t seem like a lot, but over time, even that small percentage of rays adds up.
Protecting Your Skin
Limiting unprotected exposure to sunlight and protecting your skin when you’re in the sun are important steps for keeping your skin looking healthy and more importantly, preventing skin cancer. The Skin Cancer Foundation has great educational resources on sun exposure and skin health. Chemical sunscreens function by absorbing harmful UV rays. Mineral sunscreens, like zinc oxide or titanium dioxide, function by blocking the sun’s UV rays. Both are effective for sun protection.
Chemical sunscreen active ingredients include:
Oxybenzone
Octisalate
Octocrylene
Homosalate
Octinoxate
Two reports released by the FDA in 2020 show that chemical sunscreen agents absorb through the skin and accumulate in the body at potentially unsafe levels. Previous research has linked chemical sunscreen agents to endocrine disruption and reproductive harm, but no comprehensive safety data on internal use in humans is available on these ingredients. Chemical sunscreens may also be implicated in worsening skin conditions like eczema in people with sensitive skin.
View from Grand Viewpoint Overlook in Canyonlands National Park near Moab, Utah
When choosing a natural sunscreen, look for zinc oxide or titanium dioxide as the active ingredient. These sunscreens tend to be thicker and less absorbable than chemical sunscreens so they can take some getting used to but it’s worth it to protect your skin and your overall health. The Environmental Working Group has great resources on choosing chemical-free sunscreens.
Balancing Sun Exposure with Skin Protection
Sunlight is important for our health but too much sun exposure can be damaging to our skin and lead to skin cancer. Balancing our time spent in the sun with protecting our skin is key for reaping the benefits of sunlight. If you are going to be exposed to direct sun, especially in the middle of the day, wear sunscreen on exposed skin. Sunscreen needs to be reapplied regularly if you are going to be exposed to the sun for long periods of time. Mineral sunscreens block harmful UV rays from penetrating our skin and can protect us from the damaging effects of the sun.
References
McGinty, J., 2020. Sunscreen Chemicals Accumulate In Body At High Levels. [online] WSJ. Available at: <https://www.wsj.com/articles/sunscreen-chemicals-accumulate-in-body-at-high-levels-11594978201> [Accessed 9 August 2020].
Sansone RA, Sansone LA. Sunshine, serotonin, and skin: a partial explanation for seasonal patterns in psychopathology?. Innov Clin Neurosci. 2013;10(7-8):20-24.
The Skin Cancer Foundation. 2020. Sun Protection - The Skin Cancer Foundation. [online] Available at: <https://www.skincancer.org/skin-cancer-prevention/sun-protection/> [Accessed 9 August 2020].
Sunscreens, E., 2020. EWG's 2020 Guide To Safer Sunscreens. [online] Ewg.org. Available at: <https://www.ewg.org/sunscreen/report/the-trouble-with-sunscreen-chemicals/> [Accessed 8 August 2020].