With summer upon us, it’s time once again to think about sun protection as you head to the pool or the picnic. But think twice before you pick up any old bottle of sunscreen. All sunscreens are not created equal! Most people think that sunscreen only protects them from sunburn. While this is the minimum requirement of a sunscreen, choosing one with the right ingredients can protect your skin from burning, premature aging and skin cancer.
To understand the ingredients in sunscreen product, you must first understand the different types of UV radiation (UVR). UVR is the spectrum of light that is beyond what we as humans can see. These wavelengths of light are short: UVA is 400-320 nm (nanometers) and UVB is 320-290 nm. UVB radiation is chiefly responsible for acute injury to the skin or a sunburn. It typically penetrates and damages the upper layers of skin. It only accounts for a small amount of the UVR that we get from the sun, and the intensity of UVB varies throughout the year. This is why summer sun is more likely to cause a sunburn. UVB is a proven carcinogen responsible for the formation of precancerous changes as well as basal cell and squamous cell carcinomas. UVA is present at the same strength year round and accounts for 95% of UVR. It penetrates the skin deeply and is responsible for eliciting a suntan. It penetrates glass and clouds. Because of its deep penetration, UVA is mainly responsible for aging and wrinkling of skin over time. Recent research however, has shown that it too plays a role in the development of skin cancers and may possibly initiate them like UVB. UVA is also believed to be play a role in the development of malignant melanoma, the most deadly form of skin cancer.
So how does all of this relate to sunscreens? Up until this year, the FDA only required sunscreens to report their SPF factor. An SPF or “sun protection factor” only tells you how much protection from burning you have which largely relates to how much UVB protection there is. The FDA was not requiring sunscreen manufacturers to disclose how much, if any UVA protection their product provided. Therefore, someone could be applying sunscreen that protected them from burning, but still allowed skin damage leading to premature aging and skin cancers!
To understand what ingredients to look for in a sunscreen, you must understand there are 2 different types of sun protecting ingredients: organic and inorganic. Organic UV filters are chemicals that act as UV sponges, absorbing the radiation thereby protecting the skin. These usually only provide protection from UVB and include things like, oxybenzone, avobenzone and other PABA derivatives. Much better protection comes in the form of inorganic UV filters such as zinc oxide and titanium dioxide. These ingredients block and deflect both UVB and UVA rays. The diagram to the left illustrates the range of protection provided by different sunscreen ingredients.
So when sunscreen shopping, look for a product that has both a physical and chemical blocker; preferably with at least 6%zinc oxide as the main ingredient. Remember that all sunscreens do wash, rub and sweat off, so make sure to apply before heading out and every hour or two that you are outdoors. The SPF of the product should be at least 30 and the labeling now must include the terms “broad spectrum” to indicate UVA protection at least as high as the SPF.
Consider too that the only 100% sun protection is sun avoidance, so seek shade when outdoors and avoid sunbathing. Wear protective clothing and hats. Avoid outdoor activities when UVR is at its peak between the hours of 10 am and 2 pm. Sunscreen should be in addition to smart sun behavior.
