It’s important to wear sunscreen this summer (no, seriously!)

By Dede McKelvy and Grace YooIn honor of the graduation season (when the famous “wear sunscreen” article makes its annual appearance), we were asked by The Lakeville Journal to write about sunscreen. That seemed appropriate, since Grace had been trying to buy sunscreen last weekend, when, she reported, “numbers unexpectedly attacked me.” She explained: “The pharmacy’s shelf was neatly lined with bottles of sunscreen that were labeled with SPF numbers ranging from 15 to (surprisingly) 100. “Although math is not my area, SPF 100 product seemed stronger than SPF 15.“Back at the office, I proudly showed off the ‘better’ sunscreen I had bought. But unlike what I (and probably many other people worried about skin health) might think, different SPFs, or sunburn protection factors, do not have a significant influence on the degree of protection the sunscreen offers.”After doing some research on the Internet, we learned that the higher SPF numbers only increase protection up to a certain point. Dr. Steven Q. Wang is the head of dermatologic surgery and the dermatology division at Memorial Sloan-Kettering Cancer Center. He was quoted on the Internet as saying that SPF 15 sunscreen blocks 93 percent of harmful ultraviolet rays; SPF 50 blocks 98 percent; but any number after 50 only adds a minuscule amount of additional protection.Numerically, 100 is twice the size of 50. But in the sunscreen world, it doesn’t offer a double dose of protection. As part of our research here, one of the editors asked if sunscreen keeps the body from absorbing vitamin D and if wearing sunscreen might even cause a vitamin D deficiency. That would be a bad thing, especially in this day when so many people our age already get limited exposure to the sun. Vitamin D keeps bones strong, boosts immunity, fends off depression and lowers cancer risk, according to data from the National Institutes of Health. It is so important, that the government adds it to milk. But the tricky thing with vitamin D is it can only be absorbed by our bodies if we go out in the sun; the sunlight is like a key that unlocks it. So we did some more online research and found a study from King’s College London’s Institute of Dermatology, which said that sunscreen does not affect our ability to absorb vitamin D. We found this sort of cool: The institute measured vitamin D levels of 20 people before and after a tropical vacation. Half of the group wore SPF 15 sunscreen, and the other half didn’t use any sun protection. The SPF 15 wearers dodged a mean sunburn, while those who wore no sunscreen transformed into walking lobsters. But in terms of vitamin D absorption: Both groups’ vitamin D levels rose significantly throughout the trip (a good thing) and the levels remained relatively equal. The sum total of our research: Even a sunscreen of SPF 15 (blocking 93 percent of harmful ultraviolet rays) allows a healthy amount of vitamin D to be absorbed, while fending off UVA and UVB rays that cause premature skin aging and skin cancer. UVB rays are the principal culprits behind sunburn; and the deeper-infiltrating UVA rays are believed to cause wrinkling, leathering, sagging and other light-induced effects of aging. With a lack of sunscreen and excessive exposure to these harmful effects of the sun, skin cancer is dangerously plausible. If proper sunscreen is regularly applied, however, skin cancer (which affects one in five Americans) can be avoided because sunscreen shields the skin from the UV rays that can cause skin cells to mutate, rapidly multiply and form tumors. So here’s a bit of advice for people everywhere who are welcoming the sun with open arms after a brutal winter: Wear (appropriate) sunscreen.