Why we might need an evening after sunscreen
The dangers of sun exposure are well-known; skin cancer is the most common cancer in the United States. Contrary to popular belief, however, most of…
Think that sun tan protects you? Think again! (Shutterstock)
The dangers of sun exposure are well-known; skin cancer is the most common cancer in the United States. Contrary to popular belief, however, most of the damage being done on the cellular level from ultraviolet radiation occurs hours after initial exposure.
According to research from a team out of Yale University, melanin in the skin produced as a result of ultraviolet exposure (the reason skin turns tan) isn’t necessarily just the skin’s way of protecting itself.
SEE ALSO: Hidden spots you don’t check for skin cancer?but should!
The appearance of pigment is actually evidence that ultraviolet radiation has damaged the DNA in melanocytes, the cells that produce pigmentation. In other words, a tan shouldn’t be viewed as healthy; it is evidence the sun has already caused damage.
While there is truth in the fact skin with higher melanin concentrations is better protected from the ultraviolet radiation, melanin produced as a result of sun exposure does not carry the same protection as melanin present in skin at birth.
Individuals with naturally darker skin tones are not seeing the result of damaged cells, they were simply born with higher melanin concentrations. Melanin gained through a sun-induced tan, though, regardless of a person’s initial skin color, is evidence of skin damage.
Though experts have known a tan was evidence of damage, it was what happened hours after ultraviolet radiation exposure that surprised researchers.
Melanocytes in tanned skin continued to produce cyclobutane dimer (CPD), a damaged form of DNA associated with skin cancer, hours after a person was exposed. Cells not yet damaged (regular pigment) only produced CPD during the actual ultraviolet exposure. This suggests why the more a person sunbathes, the higher their risk for developing cancer.
One day we may have a post-exposure sunscreen. (Shutterstock)
“If you look inside adult skin, melanin does protect against CPDs. It does act as a shield,”explained co-author Douglas E. Brash to MNT. “But it is doing both good and bad things.”
The damage to melanocyte DNA wasn’t limited to just a handful of hours after being outside or in a tanning booth. Experts found half of the damaged DNA strands were produced during the night in a process called “chemiexcitation.” Chemiexcitation occured when ultraviolet radiation excited enzymes in a skin cell and that energy then transferred to DNA in the dark when no more ultraviolet radiation was present.
The findings add to the long list of reasons to avoid unprotected ultraviolet exposure. According to the American Academy of Dermatology, 1 in 5 Americans will develop skin cancer in their lifetimes, and more than 2 million people in the United States are affected annually.
SEE ALSO: This type of skin cancer primarily affects Hispanics and other dark-skinned minorities
Though considered the most common form of cancer and highly treatable, skin cancer is also largely preventable. It is in the hopes of further prevention that the Yale team intends to investigate their findings further.
Brash and his colleagues believe the preliminary data could eventually lead to the development of an “evening after” sunscreen product, designed to prevent melanocytes from producing CPDs post-exposure.
