Written by: Dr. Baili Clarke, ND
There is no doubt that we all love the summer sun! It brings much needed light, warmth and good-times in the great outdoors. Not only that, but it is a primary source of the oh-so-important Vitamin D which provides many health benefits including strong bones, improved mood, and a healthier immune system. However, as we continue to learn about the various risks associated with excess sun exposure, such as skin damage, premature aging and skin cancer, and as the rates of these conditions continue to rise, it becomes important to remain informed and updated on what makes good ‘sun sense’.
There is much debate currently whether sunscreen is as effective as once thought in protecting against damage from the sun. Although it is well established that excess ultraviolet (UV) radiation and an individual’s skin sensitivity level are significant risk factors for developing skin cancer (90% of non-melanoma types such as Squamous Cell Carcinoma and Basal Cell Carcinoma and 65% of melanoma types), it is less clear whether regular use of sunscreen actually prevents all types of skin cancer. There appears to be strong evidence showing significant reduction in rates of actinic keratosis (sun induced skin damage that may change to skin cancer) and Squamous Cell Carcinoma with regular sunscreen use, but not for Basal Cell Carcinoma and with conflicting results for Melanoma. Why UV radiation avoidance and sunscreen use is more effective at protecting against one type of skin damage over the other is still unknown, but may be explained by the complex nature of cancer and the multiple factors involved such as individual skin-type & sensitivity level, intensity and duration of UV exposure, genetics, immune system functioning, and Vitamin D status. Thus, although only a part of the solution, sunscreen does appear to have a role to play in protecting against skin damage and certain types of skin cancer when used appropriately.
Unfortunately, choosing the best sunscreen requires some homework as all sunscreens are not created equal. The latest recommendations from Health Canada suggest using only sunscreen with broad spectrum coverage for both UVB and UVA radiation. This is because, although high-energy UVB rays are responsible for burning skin and damaging DNA, it is now understood that UVA rays may be equally as damaging on a more subtle, deeper level (without the blistered skin as a reminder). As such, Health Canada requires a minimum ratio of UVA to UVB of 1:3 for all approved sunscreens and recommends consumers choose a sunscreen with a minimum SPF of 15 (with higher protection from a SPF of 30-50). Furthermore, it is no longer acceptable to have ‘waterproof’ and ‘sunblock’ written on the label, and sunscreens with a SPF >50 should be labelled only as SPF 50+ as claims above this are misleading.
Other concerns with sunscreen are the various chemicals used in them to filter out UV radiation. Of particular concern are the chemicals oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate. Most sunscreens contain a combination of these potentially toxic chemicals, with oxybenzone being the most common and problematic. The Environmental Working Group (EWG) recommends that consumers avoid oxybenzone because it can penetrate the skin, cause allergic skin reactions and may disrupt hormones. Another common and potentially harmful ingredient is retinyl palmitate, a synthetic form of preformed Vitamin A that has been shown to speed the growth of skin tumors and lesions when on sun-exposed skin. Alternatively, EWG recommends using mineral based sunscreens such as zinc oxide and titanium-dioxide, with a preference for zinc oxide due to its stability in sunlight and greater protection for UVA rays. For a list of the best beach and sport sunscreens that meet EWG’s strict criteria for favorable use visit http://www.ewg.org/2013sunscreen/best-sunscreens/best-beach-sport-sunscreens/. See if your sunscreen made the list!
Overall, the consensus amongst skin cancer researchers is that the best protection comes from avoidance of sunburn at all stages of life, but particularly during childhood and early adolescence. It was found that one or more blistering sunburns during childhood doubles the risk of developing skin cancer later in life. This does not mean applying a broad spectrum sunscreen with an SPF 50+ and basking in the sun for hours! Interestingly enough, it was found that those who rely on sunscreen for complete UV protection have a false sense of security and tend to spend more time in the sun, putting them at higher risk for sun damage. Good ‘sun sense’ means first protecting yourself from sunburn by avoiding direct, prolonged sun exposure during peak UV light hours, and then applying a safe sunscreen as ‘back-up’ for further protection if avoidance isn’t possible.
Be sure to follow these guidelines when practicing good ‘sun sense’:
avoid sun-tanning and tanning beds
avoid sun exposure between 10am – 2pm (highest UV radiation)
seek shade often and keep covered with protective covering (light, long sleeve cotton shirts; large brimmed hats; sunglasses) if spending excess time in the sun
DO NOT USE SUNSCREEN AS A TOOL TO PROLONG YOUR TIME IN THE SUN!
use sunscreen with both UVB & UVA broad spectrum protection
apply sunscreen generously to exposed areas at least 20 minutes before going outside and reapply every 2 hours (or more if swimming or perspiring heavily)
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Environmental Working Group (2013). Guide to Sunscreens. Retrieved from http://www.ewg.org/2013sunscreen/
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