Scientific research has confirmed that sun exposure can cause cancer. The mechanism is straightforward: “UV radiation gets absorbed into your DNA and causes little kinks, essentially the DNA equivalent of a typo,” Charlene Lam, associate professor of dermatology at the Penn State Cancer Institute, told Discover.
Usually these typos are repaired, but over time, if you get a lot of them, the chances increase that one will be missed by the repair mechanism and become a mutation that causes cancer.
The three main types of skin cancer are squamous cell carcinoma, basal cell carcinoma, and melanoma. Squamous cell carcinoma and basal cell carcinoma are rarely deadly. Melanoma is much rarer than the other two, but if not caught early, it can sometimes be deadly. Around 8,500 people in the U.S. die of melanoma each year.
According to organizations such as the American Academy of Dermatology (AAD) and the Centers for Disease Control and Prevention (CDC), the best way to protect yourself from skin cancer is to stay out of the sun, especially during the peak hours of sunlight. If you must be in direct sun between 10 a.m. and 2 p.m., the AAD and the CDC recommend wearing a hat, protective clothing, and sunscreen on exposed skin.
Explore All OptionsRead More: A Researcher Stopped Wearing Mineral Sunscreen Because of Its White Cast — Now She May Have Fixed It
Can Sun Protection Impact Vitamin D Levels
While it’s important to protect yourself from skin cancer, all that covering and slathering can interfere with absorption of vitamin D, which the body synthesizes from sunlight. A growing body of evidence also links low vitamin D to an increased risk of a variety of ailments. For example, a 2020 study published in the Journal of the American Heart Association found that exposure to sunshine was linked to lower blood pressure.
And it’s not just cardiovascular disease. According to the National Cancer Institute, studies have found that higher vitamin D levels are associated with a lower risk of colorectal cancer, and in several types of cancer, patients with higher levels of vitamin D are less likely than those with lower levels to die of their cancer. In what seems like some kind of weird paradox, that applies to skin cancer, too. According to a study published in the Journal of the National Cancer Institute, sun exposure has been associated with increased survival in patients with melanoma.
The solution would seem to be to avoid the sun and take vitamin D supplements. But multiple trials have failed to show that vitamin D supplementation makes much difference. This could mean that the benefits of vitamin D come only when you get your D the old-fashioned way, from the sun. Or it could mean, as Anika Lucas and Myles Wolf, researchers at the Duke University School of Medicine, speculated in a 2019 JAMA editorial, that the benefits of sunlight could be due to some other factor or combination of factors that observational studies aren’t capturing.
Sun Protection Varies From Person to Person
In light of all this, some experts are beginning to take a more nuanced approach to sun exposure. Richard Weller, a researcher at the University of Edinburgh, studies the effect of UV light on systemic health. (He’s the lead author of the 2020 study on blood pressure and sunlight mentioned.) Weller said that, at least for people with lighter skin tones in northern latitudes, we’ve definitely gone overboard on the advice to cover up and slather on.
And it may not apply to people with darker skin tones. A 2021 study in JAMA Dermatology suggests that UV exposure appears to have a smaller role in melanoma cases for people with darker skin tones, when compared to people with lighter skin tones.
In 2023, the Cancer Council Australia and the Australasian College of Dermatologists issued new sun protection guidance that takes into account not only skin color, but time of year, what part of the country people live in, and other factors.
Meanwhile, researchers are continuing to investigate the role of sunlight in health, hoping to answer the question: “How much is too little?”
This article is not offering medical advice and should be used for informational purposes only.
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Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- This article references information from a study published in the Journal of the American Heart Association: Does Incident Solar Ultraviolet Radiation Lower Blood Pressure?
- This article references information from the Cancer Society: Key Statistics for Melanoma Skin Cancer
- This article references information from the AAD: Shade, clothing, and sunscreen
- This article references information from the CDC: Sun Safety Facts
- This article references information from the NIH: Vitamin D and Cancer
- This article references information from a study published in the Journal of the National Cancer Institute:Sun Exposure and Mortality From Melanoma
- This article references information from a study published in JAMA: Vitamin D and Health Outcomes
- This article references information from a study published in JAMA Dermatology: UV Exposure and the Risk of Cutaneous Melanoma in Skin of Color
- This article references information from the Australian Skin and Skin Cancer Reseach Centre: Balancing The Harms And Benefits Of Sun Exposure
