By Dr. Renata Prado
Board-Certified Dermatologist and Fellowship-Trained Mohs Surgeon
I am frequently asked about vitamin D and my thoughts on the risk of deficiency with our recommended sun protection. We all agree on the importance of vitamin D. It is known to play many important roles in our body, such as calcium and phosphorus absorption, bone growth, and immunity. In recent years, there has been an increase in knowledge of the benefits of vitamin D and the possible consequences of its deficiency. Many patients are now worried that their vigilant sun protection may result in vitamin D deficiency.
Well, let’s look at the facts:
• Do we need vitamin D? There is no question about that. It plays important roles in our body and we want to make sure we have adequate levels.
• How do we get vitamin D? Vitamin D is produced on our skin when it is exposed to sunlight. The sun’s ultraviolet B (UVB) rays interact with a protein called 7-DHC in the skin, converting it into vitamin D3, the active form of vitamin D. Vitamin D is also obtained from diet and supplements.
• How much sun do I need to make vitamin D? The truth is, it doesn’t take much sun exposure for the body to produce vitamin D. It is believed that 10 to 15 minutes of exposure to arms, legs, abdomen, and back, two to three times a week, make all the vitamin D our body needs. After that, the production stops.
• Now, the important question: does sunscreen use lead to vitamin D deficiency? This is a valid question and it has been the subject of many studies. The answer is no, sunscreen does not seem to lead to vitamin D deficiency. Most studies published to date have not only shown no association between sunscreen use and vitamin D deficiency, but some studies have even reported a positive association between sunscreen use and vitamin D levels, suggesting that their use may have increased sun exposure. One of the explanations for this may be that people in the studies did not apply sunscreen in an optimal manner. However, even when studies ensured patients applied the recommended amount of sunscreen, vitamin D levels were not affected. Another explanation is that sufficient UV radiation may be transmitted through a sunscreen for vitamin D synthesis. In fact, 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, even with high-SPF sunscreens. And that’s if you use them perfectly.
In contrast, there is overwhelming evidence that unprotected sun exposure causes sun damage, skin aging, and skin cancer, while regular use of sunscreen has been shown in studies to significantly decrease your chances of developing squamous cell carcinoma, melanoma, and premature skin.
In short, unprotected sun exposure puts you at risk for any number of conditions that can permanently damage your skin, disfigure you, sometimes even kill you. And the regular use of sun protection can help keep any of that from happening.
How about those quick 10 minutes of sun exposure 3 times a week? How bad can that be?
Dermatologists advocate that even just those unprotected 10 or 15 minutes will cause DNA damage to your skin cells, in fact, UVA damage can start in less than a minute in the sun. It has also been shown that UV damage to the skin’s pigment cells (melanocytes) actually keeps developing hours after the sun exposure ends. Most importantly, there is a cumulative effect of the ultraviolet damage to the skin, as damage adds up throughout your lifetime, producing more and more genetic mutations that keep increasing your lifetime risk of skin cancer.
The rapid onset of DNA damage and the harmful cumulative effects of both UVA and UVB exposure throughout our lives are the reasons that the vast majority of dermatologists recommend intentional sun protection.
And since we are talking about it: to protect against UV-induced skin cancer, dermatologists recommend a comprehensive sun protection plan that includes seeking shade, wearing protective clothing, and applying a broad-spectrum, water-resistant sunscreen with an SPF of 30 or higher.
If not from UV exposure, how can you obtain enough vitamin D?
Even with your diligent application of sunscreen and the use of sun-protective clothing, it is likely that, as noted above, you are still producing some vitamin D via your skin. However, this may not be enough, so dermatologists recommend that you acquire vitamin D from a combination of diet and supplements. Fatty fish such as salmon, mackerel, and tuna are especially good sources. Small amounts are also present in egg yolks, beef liver and cheese, and many common foods such as milk and orange juice are fortified with vitamin D. There are also over the counter supplements of vitamin D that you may take to get the daily allowance of 600 International Units (IU) recommended by the Institute of Medicine and The Skin Cancer Foundation for the average person between the ages of 1 and 70 (400 IU is recommended for infants under age 1 and 800 IU is recommended for everyone over age 70). Always talk to your doctor before taking any supplements.
Dr. Renata Prado is a board-certified dermatologist and Mohs Surgeon. Dr. Prado specializes in the diagnosis and treatment of skin cancers. She is part of Vanguard’s Colorado Springs dermatology practice in Briargate and Broadmoor.
Vanguard Skin Specialists began as a Colorado Springs dermatology practice and now has an additional office in Canon City, Pueblo, and Woodland Park. Vanguard specializes in the diagnosis and treatment of skin cancer, and also offers general dermatology, plastic surgery, and aesthetic medicine.