Vitamin D: Let the Sun Shine?
Ultraviolet (UV) rays from the sun cause harm to the skin and raise the risk of skin cancer. As a result, many people have taken steps to lower this risk, such staying out of the sun or putting on sunscreen.
These changes lower the risk of cancer, but also block a major health benefit. The sun’s UVB (a type of UV ray) rays can stimulate the Recommended Dietary Allowance of vitamin D (400-800 units) in as little as 5 to 30 minutes twice a week. This has left many wondering whether the sun's vitamin D benefits are enough to outweigh its risks.
About Vitamin D
Vitamin D offers protection against heart disease, osteoporosis, and many types of cancer, such as breast, prostate, and colon cancers. The benefits of vitamin D have been well researched. The debate is now about where you should get your vitamin D.
Fish and fish liver oils have some of the highest sources of vitamin D. But most people get their vitamin D from fortified foods like milk and orange juice. Even so, most people do not get enough Vitamin D through food sources.
Vitamin D can be taken as a supplement, usually in a pill that also has calcium. But this does not have the same amount of vitamin D as the sun. High amounts of vitamin D pills have also led to harmful levels of calcium in the body. This does not happen from vitamin D from the sun.
You can get vitamin D from the sun, but how much you get may not be the same for each person. The summer sun can make enough vitamin D within 15 minutes for people with fair skin, but it may take 6 times longer in people with darker skin.
UVB rays are also weak and can be blocked by clouds, smog, and glass windows. The sun's UVB rays also do not reach the Earth during certain times of the year in far north and far south places like Washington state and Vermont. There is far less vitamin D during these times of year.
And of course, the sun is a poor choice for people who have a higher risk of skin cancer.
Sun Versus Pills
There is no doubt that a lot of sun exposure harms the skin. Staying out of the sun lowers this risk, but more people in healthcare are now leaning toward the light. More research needs to be done to find out exactly how much sun raises the risk of skin cancer and who may be at higher risk. At the same time, the growing interest in vitamin D will also prompt companies to try to make pills better.
There are many things that play into our risk of getting disease, such as our environment, lifestyle habits, and genes. You should act based on your own health and family history.
No changes have been made to current sun safety guidelines, but more debate will be ahead. For now, it may be best to find balance:
- Check the UV index in the weather forecast. A severe UV index means that burns can happen quickly. You will need to protect yourself on these days.
- Do not ban outdoor activities. Think about the length of time you are spending outdoors, the UV index, and the weather.
- Do not sunbathe or use tanning machines.
- Add an outdoor lunchtime walk of 10 to 15 minutes. Do this a few days each week.
Talk to your doctor about your risk factors for skin cancer. People who have a personal or family history of it will need to follow safety steps closely. They may also need to raise vitamin D levels through diet or pills.
American Cancer Society
Eat Right—Academy of Nutrition and Dietetics
Canadian Cancer Society
Dietitians of Canada
Skin cancer prevention—patient version (PDQ). National Cancer Institute website. Available at: https://www.cancer.gov/types/skin/patient/skin-prevention-pdq. Accessed July 7, 2021.
Sun safety. Environmental Protection Agency website. Available at: https://www.epa.gov/sunsafety. Accessed July 7, 2021.
Vitamin D. National Institute of Health Office of Dietary Supplements website. Available at: https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional. Accessed July 7, 2021.
Vitamin D deficiency in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/vitamin-d-deficiency-in-adults. Accessed July 7, 2021.
Vitamin D intake and supplementation. EBSCO DynaMed website. Available at: https://www.dynamed.com/drug-review/vitamin-d-intake-and-supplementation. Accessed July 7, 2021.
Last reviewed July 2021 by EBSCO Medical Review Board Last Updated: 7/7/2021