Summer is here, and that means an increased focus on avoiding the sun’s harmful UVA and UVB rays by covering our skin, seeking shade and using sunscreen. The sun does bring some positive health benefits though, namely vitamin D, which allows our body to absorb nutrients like calcium and supports healthy immune function. At a time when several studies have potentially linked adequate levels of vitamin D with protection from COVID-19, it’s understandable that many people may be interested in increasing their vitamin D intake. But how can we balance the body’s need for vitamin D with the very real risks of skin cancer from overexposure to the sun?
Sources of Vitamin D and Risks from Deficiency
Our bodies create vitamin D when our skin is exposed to sunlight. Some foods naturally contain vitamin D (e.g., wild salmon, tuna, eggs) and other foods are often fortified with it (e.g., milk, breakfast cereals, orange juice). However, because very few foods contain significant amounts of vitamin D, it’s unlikely you’ll get all the vitamin D you need from food alone. The third way to get vitamin D is by taking it as a supplement.
Even with all this vitamin D available, around 40 percent of U.S. adults are vitamin D deficient. Vitamin D deficiency has been linked to osteoporosis, cancer, depression and other serious health effects. Vitamin D deficiency is even more prevalent among Hispanic adults (63 percent) and African-American adults (82 percent). This is likely caused by several factors, including a lack of quality health care and lack of health education.
Another major reason is that darker-skinned people naturally have more melanin in their skin. Melanin acts as a natural sunscreen and means that people with darker skin tones need more sun exposure to make the same amount of vitamin D as a lighter-skinned person. People of all skin tones also make less vitamin D as they age, which is why the recommended daily amount of vitamin D increases for adults age 70 and up.
How Much Sun Is Enough to Make Vitamin D?
If you’re curious how much sun exposure you need each day to get enough vitamin D, the answer is “probably less than you think.” Factors like location, time of day, skin color and amount of bare skin mean there’s no magic number of minutes, but we do have some rough estimates. A UK study found that nine minutes of midday summer sun was enough for Caucasian adults to maintain healthy vitamin D levels. Another study found that 30 minutes of midday sun in Norway was equivalent to about 15,000 IU of vitamin D. For comparison, the daily recommended amount for adults age 18-70 is 600 IU.
However, it’s estimated that darker-skinned people need between 30 minutes and three hours longer than these ballpark figures to produce enough vitamin D. Another study suggests that people with darker brown skin who tan easily and rarely burn, such as people of South Asian origin, may only need 25 minutes of sun exposure to produce enough vitamin D. “The darker the skin, the more it’s protected against skin cancer but the less able it is to absorb UVB rays,” says Robyn Lucas, a former epidemiologist at Australian National University. “If you’re already tanned or of Hispanic origin, you need maybe 15 to 20 minutes. Black skin may require six times the sun exposure to make the same vitamin D levels as a very fair-skinned person.”
It’s worth noting that the body breaks down excess vitamin D past a certain level, so getting a little sun exposure every day is much better than trying to soak up a week’s worth of sun all at once.
Consequences of Overexposure to the Sun
Based on the estimates above, if you spend lots of time outdoors, it’s likely you already get enough vitamin D from the sun. Most of us aren’t perfect at covering up every time we go outdoors or reapplying sunscreen every two hours. However, if you follow sun-protective behaviors regularly, especially if you have darker skin, you may not be getting enough vitamin D. If that’s the case for you, consider adding foods rich in vitamin D to your diet or taking a vitamin D supplement instead of opting for additional sun exposure. Remember that overexposure to the sun’s rays can lead to painful sunburns, eye damage, premature skin aging and skin cancer.
“Just being outdoors, you get a fair amount of sun exposure and some sun-related generation of vitamin D,” says Yale Medicine endocrinologist Dr. Karl Insogna. “Because skin cancer, particularly melanoma, can be such a devastating disease, it’s best to use sunblock when outdoors in strong sunlight for any prolonged length of time. Because this may limit the amount of vitamin D you get from sun exposure, make sure your diet includes sources of vitamin D from foods or supplements.”
The LHSFNA’s annual Sun Sense Plus campaign raises awareness about the dangers of skin cancer and heat illness by distributing products and educational materials to LIUNA members. LIUNA District Councils, Local Unions, training centers, LECET funds and signatory contractors can order sunscreen, lip balm, neck flaps, cooling cloths, insect repellent towelettes, tick keys, pamphlets and posters by using this order form.