27
July
2018
|
15:00
Europe/Amsterdam

U of A dermatologist discusses whether sunscreen causes cancer, and provides sun safety tips

Expert offers advice for sunscreen skeptics.

By LESLEY YOUNG

There’s a reasonable approach to sunscreen use—even for those who are skeptical about its safety, says a University of Alberta dermatologist.

“From a philosophical perspective, some people may not use sunscreen because they believe it’s not a natural way to live, or they are worried it may cause cancer, or they are concerned about sunscreen chemicals polluting water,” said Robert Gniadecki.

“However, it’s important to protect your skin from the sun. And the role sunscreen plays in helping to reduce your exposure to ultraviolet rays can be a balanced one,” he added.

He addresses some commonly held beliefs by sunscreen skeptics and provides tips with public safety in mind.

Sunscreen causes cancer

Gniadecki said the fear that sunscreen causes cancer came from a number of poorly designed animal model studies.

“You can’t assume the same results will occur in humans,” he noted, adding that it’s extremely difficult to prove or disprove anything causes cancer in studies.

“For example, sunscreen chemicals are ubiquitous and we are all exposed to them whether or not we use sunscreen.”

The bottom line is that the studies suggesting sunscreen causes cancer are junk science, he said.

“On the other hand, the very best quality studies—randomized controlled trials comparing those who regularly wear sunscreen with those who don’t—show sunscreen may help to protect against the deadliest form of skin cancer, melanoma, and also reduces non-melanoma skin cancers.”

Advice for sunscreen skeptics: Hit up other lines of defence before turning to sunscreen, including avoiding sun exposure when UV rays are the strongest—noon to 3 p.m.—donning clothing and a hat, and sticking to shade, said Gniadecki.

Sunscreen can cause skin sensitivities

The actual sunscreen filter ingredients are less likely to cause a skin sensitivity than some fragrances and preservatives that may be contained in sunscreen, said Gniadecki.

He does not recommend using sunscreen on infants, who should be kept out of the sun altogether, or young children, because it’s usually not enough sun protection.

“Instead, make sure they are wearing a hat and clothing that covers up the skin. If you do have sensitive skin, try a small amount of the product on your arm and check for a reaction 48 hours later.”

Or, if you are allergic to chemicals in sunscreen, the Canadian Dermatology Association recommends looking for ones that contain titanium dioxide and zinc oxide, which reflect rather than absorb the sun’s rays and are much less likely to cause a reaction.

Advice for sunscreen skeptics: “In our climate, 90 per cent of sun exposure happens between June and August,” said Gniadecki. He suggested wearing sunscreen only during those months if you can’t protect your skin in other ways.

Sunscreen will reduce my vitamin D

While direct sun exposure is vital to help our bodies produce vitamin D, a disease-fighting antioxidant with increasingly positive health benefits, we need to take supplements because there’s too little sun exposure in our climate to maintain consistent vitamin D levels year-round, said Gniadecki.

Advice for sunscreen skeptics: Good news. “There is good research on this: the amount of sun exposure you need to produce vitamin D is very little—just 10 minutes,” said Gniadecki.

So go ahead and bask your face and hands sunscreen-free in the sun once a day for 10 minutes, he said. “Just remember this only works in the summer in our climate.”

Sunscreen doesn’t work anyway

Obviously sunscreen works—it’s a barrier designed to either absorb or reflect the sun’s UV rays from your skin, said Gniadecki. If you find you are burning even with use, chances are you didn’t apply it properly.

Sunscreen SPF (sun protection factor) is a measure related to how long it takes for your skin to burn without any protection versus the appropriate amount of sunscreen. However, said Gniadecki, SPF is measured by applying two milligrams of cream per square centimetre of skin surface.

“Very few people apply that much sunscreen,” he said. “Studies show that the normal person applies about half of this, or half a milligram to one milligram per square centimetre. So your actual SPF drops by half or more.”

Advice for sunscreen skeptics: Sorry, there is none. If you’re going to use sunscreen instead of clothing or shade to protect your skin, you may as well put on the right amount.

“You can compensate for insufficient application by increasing the SPF level,” said Gniadecki. “But really, users should just make sure they are putting on a visible layer, ensuring their skin does not feel dry or has dry patches after.”

Some people contend tanning without burning is a safe way to enjoy the sun. Gniadecki noted that while skin burns are indeed a key risk factor for melanoma later in life (particularly cumulative sunburns earlier in life), it’s very difficult to get a tan without experiencing some harmful UV exposure.

We can’t isolate ourselves from the sun completely, added Gniadecki. “Feeling the warmth of the sun on our skin is a true pleasure in life.”

In the end, he said, it’s about making reasonable choices based on the evidence and finding a healthy balance between protected and unprotected sun exposure.