Should you soak up that vitamin D or shield yourself from sunburn?Q:I am confused by all the conflicting information regarding proper skin care and sun exposure. We are supposed to use sunscreen, but then I hear that this blocks vitamin D absorption. What is the best answer for healthy skin and body?— Molly Myers, DenverA: Skin is the largest organ anywhere on the human body, weighing about 6 pounds and covering a surface area the size of a twin bed. It is composed of water, protein, fats (lipids), minerals and other chemicals. The skin regenerates itself every 27 days, no small feat since it also protects us from infections and germs, and regulates our temperature. With nerve endings at the surface, skin delivers feelings of sensation, giving us reactions to pain, pleasure, hot and cold.
It behooves us to protect and care for our skin using the best available information. Denver dermatologist Richard G. Asarch is concerned with the damage that ultraviolet light does to the skin through sun exposure and tanning beds because ultraviolet light is a known risk factor for the development of the three most common skin cancers: basal cell and squamous cell carcinomas, and melanoma.
As for sunscreen, Asarch is of the opinion that the best product is one that you will use. That being said, it is important to understand that there are two wavelengths of ultraviolet light that can damage the skin: UVB, the one that causes sunburn, and UVA, which damages the skin in more subtle ways that rarely involves redness or burning.
Sun protection factor is a measurement system to help choose the amount of protection for UVB, not UVA, Asarch says. “An SPF of 15 will block out about 93 percent of UVB, while SPF 30 will block out nearly 97 percent.” Many ingredients block UVB, but only three will block UVA: zinc oxide, titanium oxide and avobenzone.
“So far, there is no SPF system or standards to note on a package regarding protection against UVA,” Asarch says.
Vitamin D is known as the “sunshine vitamin” because your body manufactures it when you are exposed to sunlight. It is also available through the diet via fish, fish oil, egg yolks, cheese and beef liver. Vitamin D is essential for strong bones, a healthy cardiovascular system and mental cognition.
Populations at risk for a vitamin D deficiency include: people who completely avoid the sun; strict vegetarians (natural sources are from animals); those suffering from milk allergies; and people with Crohn’s Disease, cystic fibrosis, celiac disease or obesity.
As for getting D from the sun, “It takes only a few minutes of ultraviolet light exposure to produce a large amount of vitamin D in your skin,” Asarch says. “One study showed that by just exposing your head, neck and arms to four minutes of noontime Denver sun is all you need to produce enough for the day.”
Once your skin produces 20,000 units of vitamin D, additional exposure actually begins to degrade the vitamin because our skin is programmed to not make too much.
Because vitamin D is fat-soluble, oral supplements can become toxic if taken in excess. He recommends staying with the recommended daily amount of 1,000 IU per day unless otherwise prescribed.
According to the American Academy of Dermatology, it is best to obtain vitamin D from natural nutritional sources and supplements, rather than through exposure to the sun. When you go outside, apply sunscreen 30 minutes before going out and reapply at least every two hours, especially if swimming or exercising.
Linda J. Buch is a certified fitness trainer in Denver; linda@ljbalance.com.
