Alan Frischer, MD, MPH
Summer is upon us, and it has been sunny and hot. Despite my own fair complexion, I love Southern California and I love the outdoors. We all need to protect ourselves from the sun’s harmful rays. For those of us who, as I do, insist on spending time outside, one of the key options for avoiding sun damage is the liberal and frequent use of sunscreen. There is new information regarding its safety and use.
I am often asked what the best exercise is. The answer is, of course, that the best exercise is the one that we are willing to do. The same is true for sunscreen! While sunscreens are not all equal, the best one is the one that we will use generously and correctly. However, there are significant differences between them.
What is a broad-spectrum sunscreen? We need protection against two types of ultraviolet light, UVA and UVB, and a broad-spectrum sunscreen protects us from both. UVA rays prematurely age the skin, causing wrinkling and age spots. UVB rays burn the skin. Too much exposure to either type of light can cause skin cancer.
What is SPF, and how much do we need? SPF stands for sun protection factor, and is a measure of how well the sunscreen protects against UVB rays (UVA protection is not rated). Manufacturers calculate SPF based on how long it takes to burn skin treated with the sunscreen as compared to without. The recommendation is to use one with an SPF of at least 30. Once the SPF exceeds 50, there is only a small increase in UV protection. Regardless of the number, sunscreen lasts the same amount of time on the skin.
Keep in mind that even when applied well, sunscreen will wash off during swimming or sweating, and leave us unprotected. Sunscreen must be water resistant if we plan to be in the water. “Water resistant” means that the SPF is maintained for up to 40 minutes in water. If it states “very water resistant,” then the SPF will be maintained for up to 80 minutes in water.
How do the ingredients of sunscreens vary? Sunscreens contain filters that reflect or absorb UV rays. The two main types of filters are organic and inorganic. Organic filters absorb UV radiation and convert it to a small amount of heat, and include cinnamates, salicylates and benzophenones. Inorganic filters reflect and scatter UV radiation, and include titanium dioxide and zinc oxide.
The most recent FDA guidelines now generally recognize sunscreens as safe and effective (GRASE) that use two inorganic sun-blocking ingredients: titanium dioxide and zinc oxide. However, chemicals in some sunscreens with organic filters are absorbed into the body at levels high enough to raise concerns about potentially toxic effects. Bloodstream levels of oxybenzone, avobenzone, octocrylene and ecamsule increased dramatically for four days after use. At this time, the FDA recommends that we avoid sunscreen with oxybenzone.
Sunscreens come in different styles. Creams tend to be best for dry skin, while lotions are often thinner and less greasy, and preferred on larger areas. Gels work well in hairy places, like the scalp or chest. Sticks are useful when applying around the eyes. Sprays may be easier to apply on children, but never spray near the face.
Consider these suggestions:
Whenever possible, the first line of defense is to avoid sun exposure. Consider staying out of the sun at peak hours; typically between 10am and 4pm. Water, snow, and concrete reflect light and increase the risk of sunburn. Wear protective clothing, including pants, shirts with long sleeves, sunglasses, and hat.
Use sunscreen on all exposed skin surfaces, including scalp, feet, and lips.
UV rays pass through clouds, so use sunscreen even when it is cloudy.
Apply generous amounts of sunscreen to dry skin, 15 minutes before exposure.
Reapply sunscreen every two hours.
Keep an eye on the expiration date.
Children under the age of six months should not use sunscreen. Keep them out of the sun.
Regardless of issues surrounding the safety of a sunscreen’s particular ingredients, the evidence for using it – vs. NOT using it - is overwhelmingly positive. The benefits of avoiding sun damage significantly outweigh any possible risks. I urge you to use sunscreen generously, and often!