Now that it’s summer, the clouds are (mostly) gone and the days are long, and wearing sunscreen all the time is more important than ever, dermatologists say.
But recent press coverage of a supposed epidemic of vitamin D deficiency has people scratching their heads: Do I keep slathering on the sunscreen or occasionally go bare in the sun to get some vitamin D?
A spate of books and proclamations by doctors and other experts casts vitamin D as the key to preventing cancer, alleviating arthritis pains, boosting energy and ensuring general health and happiness. The sun’s rays are a major source of vitamin D for humans, and so some of these D-boosters are recommending that people leave the sunscreen off for a little bit every day.
But some local dermatologists, and the American Academy of Dermatology, say the vitamin D you can get from supplements is just as good as what you would get from the sun — and you won’t risk skin cancer or a burn.
Medical research makes it clear that sun exposure causes cancer, so you’re better off covering up and taking a supplement, said Dr. Lillian Soohoo, a practicing dermatologist in Mountain View and an instructor in dermatology at Stanford Medical School.
“We do know pretty well that the sun leads to skin cancer,” she said. “In terms of what’s a safe dose, we don’t really know.”
Dr. Tin Tin Tun, a dermatologist at Palo Alto Medical Foundation in Mountain View, agrees that vitamin D supplements are better than sun exposure. And if you eat enough of the foods that are fortified with vitamin D, like milk and cereal, you may not even need a supplement.
Vitamin D is crucial for bone and tooth health, and might help prevent some cancers, said Soohoo.
“Vitamin D is a really hot topic because it may do more than we understand,” she said. The National Institutes of Health recommends 200 IU (International Units) per day for babies and kids and up to 600 IU per day for the elderly, with the necessary dose gradually increasing as you age.
Despite this need, she said, getting the recommended daily allowance of vitamin D through the sun is still not worth the risk of exposing your skin.
How to cover up
So with a dizzying array of sunscreen products with sun protection factors (SPF) of up to 100, and even clothes that promise sun damage prevention, what’s the best way people can protect themselves and their kids from the sun?
If price is a factor, there’s no need to pay more for a sunscreen with an SPF higher than 15, said Dr. Tun. That will block about 92 percent of the sun’s rays, she said. SPF 30 is only slightly higher at 95 percent. But a lower SPF means you need to reapply more often to get enough protection.
Ideally, people should apply sunscreen 15-30 minutes before going outside, and reapply every two hours, Tun said. For people with sensitive skin (or for kids who need to be ambushed or restrained just to get slathered with sunscreen), a higher SPF might be a good idea.
Almost all sunscreens sold in the last few years protect against both kinds of damaging sun rays, UVA and UVB, Tun said. “UVB causes immediate damages of sunburn like burns and tans, and lately we’ve found that UVA can do long-term damage like wrinkles and spots,” she said. She advises checking the label to make sure a sunscreen offers “broad spectrum” protection.
People who are in the water a lot during the summer should at minimum use waterproof sunscreen, but would be better off wearing a rash guard instead of a swimsuit to cover their torso and arms, Soohoo said.
As for those special clothes with a “UPF” number on them, they’re not necessary, but aren’t a bad idea, either. Tun said she likes them in some situations, especially if they are replacing a white T-shirt, which has an SPF of only 4. (An SPF of 4 means you can stay out in the sun four times as long without burning than if your skin was bare.)
“Melanoma is the most common cause of cancer deaths in 20- to 40-year-olds,” Soohoo said. She compares the cancer risk of the sun to that of smoking cigarettes.
“I ask kids, would you become a smoker when you’re an adult?” she said. They tell her, “No way!” — but some still believe it’s OK to get a tan when they’re young.
Tun and Soohoo agree that the federal government needs to do a better job of educating kids about the dangers of the sun.
