With the Summer sun comes signs of danger

A British research team reported that a quarter or more of cells in the skin of middle-aged people have suffered sun-induced DNA damage. Although the cells were outwardly normal, the mutations that occurred could be the first stages of cancer.

Douglas E. Brash, a biophysicist at Yale University School of Medicine who has studied ultraviolet damage to cells for more than 40 years and wrote a commentary on the British study, described the new findings as “a canary in a coal mine” and a warning to take the effects of ultraviolet radiation, whether from sunlight or tanning beds, more seriously.

It is especially important, he said, “to be very conscientious about protecting young children,” who are more susceptible than teenagers and adults to ultraviolet-induced mutations.

“A lot of damage occurs when people go to the beach,” Dr. Brash said. “While the body does a great job of repairing the damage and gets 99.9 percent of things right, every once in a while, you do get a mutation that may make a cell resistant to death, allowing it to form a clone that can become a cancer.” A recently published study by Dr. Brash’s team at Yale, showed that much of the harm to skin cells caused by ultraviolet radiation occurs hours after the exposure has ended. Even in the dark, substances formed during UV exposure continue to damage melanin, the pigment that gives skin its color. Some consumers believe that choosing a more expensive sunscreen with a sky-high S.P.F. number like 70 or 100 will provide complete protection. However, the FDA has not determined that an S.P.F. of more than 50 has any added benefits.