Can sunscreen be toxic?
There are two types of active ingredient in sunscreens: chemical and mineral filters. Some chemical filters have been shown in preliminary studies to be potential hormone disruptors. Oxybenzone for example is a potential hormone disruptor. Other chemical filters may have similar effects. More research is need to clearly define the risk associated with these compounds. For now, chose products that used physical blockers such as zinc oxide and titanium dioxide if you are worried about these ingredients.
With regards to mineral ingredients in sunscreen, they can also be toxic if they reach the lungs or if they get through the skin. It is unlikely that these chemicals could go through the skin. However, the FDA has recently announced that it will take a closer look at the safety of spray on sunscreens to make sure that they are not dangerous for our lungs. The concern with spray on sunscreen use is that in children especially, some of the sunscreen could reach the lungs if the child is unable to hold their breath during application. Animal research has led to the suspicion that titanium dioxide may predispose to lung cancer. Inhalation of zinc oxide can also lead to significant health problems such as fever, fatigue and cough. However, the evidence of harm is mainly theoretical and only for improper application of these products. Meanwhile the benefits for the prevention of skin cancer are clearly established.
Most of the research shows that there is no health concern with using sunscreen.[i] Research confirms that if sunscreen is used appropriately, the benefits far outweigh the risks.
Is a tan healthy?
Sun damage accumulates overtime with 23% of the photo damage occurring by age 18 and 74% by age 59.[ii] The use of sunscreen decreases the risk of developing specific types of skin cancer.[iii] The use of UV protection is therefore important to prevent sun damage. Given that the damages associated with UV ray are cumulative, sun exposure should be avoided whenever possible. Tanning should therefore be avoided.
Does having a tan protect from sun damage? What about sunburns?
Avoiding sunburns is absolutely essential especially in young children. One blistering sunburn in children or adolescents doubles the risk of developing melanoma. If you have suffered from more than five sunburns, your risk of developing melanoma also doubles. Unfortunately, surveys show that almost half of us get sunburnt at least once a year.
A tan is our skin’s natural way to protect itself from sun damage. Having a tan has been associated with modest sun protection, roughly the equivalent to using sunscreen with SPF 2 or 3. Studies show that tanning does not protect from further UV skin damage. Tanning can therefore not be recommended as a strategy to prevent UV induced skin damage.[iv]
How do natural sunscreens work?
Natural sunscreens relies on a physical sun blocker, typically zinc oxide which acts by blocking the rays from the sun. Physical sun blockers offer good UV protection, are stable in the sun and are particularly effective at blocking UVA rays. Their main disadvantage is that they leave a white and chalky look.
What about studies that show that sunscreen users have a higher risk of developing skin cancer?
Several studies have now shown that people who regularly use sunscreen are less likely to develop skin cancer such as squamous cell carcinoma and melanoma. For example, a recent Australian study established that regular use of sunscreen decreased the risks of developing melanoma by 50%.[v]
The problem with sunscreens is that their use can lead users to spend more time in the sun. This has been well documented in studies with the user spending 13 to 39% more time in the sun.[vi] Using sunscreen with a higher SPF also increases time spent in the sun. This over reliance on sunscreen can lead to a sense of false security which causes users to spend more time in the sun thereby increasing UV skin damage and promoting skin cancer.
When all other factors stay the same, the use of sunscreen significantly reduces the risk of developing skin cancer. Please remember that sunscreen is not a substitute for covering up. Sunscreen also has limitations – it must be applied properly and frequently for instance. Also sunscreen should not be used in an attempt to spend more time in the sun.
What type of sunscreen should I use?
You should use broad spectrum sunscreen that blocks both UVA and UVB rays with an SPF greater than 15. If you want to use a natural sunscreen, select a cream that contains zinc oxide.
How about vitamin D?
A recent Swedish study reported that followed 30,000 women for 20 years established that women that avoided sun exposure had a higher risk of mortality.[vii] The study also looked at sun exposure and the risk of developing malignant melanoma, the most aggressive type of skin cancer. The results showed that women with the highest exposure were 50% more likely to develop skin cancer.
From an evolutionary perspective, lighter skin pigmentation in populations living far from the equator suggests that our bodies adjusted to less sunlight by reducing skin pigment to maximize vitamin D production in the skin. It therefore makes sense that some sun exposure is beneficial for our health. A multitude of studies now show that vitamin D is important for several chronic health problems such as heart disease, cancer and diabetes. However, vitamin D supplementation is a far safer way to improve vitamin D levels in the blood.
In conclusion, remember that UV protection is important to prevent skin damage and cancer. The use of sunscreen is an important strategy when it comes to reducing sun damage. However, other more effective strategies include wearing appropriate clothing and avoiding excessive sun exposure especially around midday. When using sunscreen, remember that using sunscreen should not encourage you to stay in the sun longer.
Sun tanning should be avoided, especially in artificial tanning beds.
Next time you are at the beach, resist the urge to sit in the sun. Find some shade, cover yourself and wear sunscreen.
Dr. Ludovic Brunel graduated with a degree in Human Nutrition from McGill University in Montreal and pursued his studies in Naturopathic Medicine at the Canadian College of Naturopathic Medicine in Toronto.
[iii]van der Pols JC, Williams GM, Pandeya N, Logan V, Green AC. Prolonged prevention of squamous cell carcinoma of the skin by regular sunscreen use.Cancer Epidemiol Biomarkers Prev. 2006 Dec;15(12):2546-8.
[iv] Miyamura Y, Coelho SG, Schlenz K, et al. The deceptive nature of UVA tanning versus the modest protective effects of UVB tanning on human skin. Pigment Cell Melanoma Res. 2011;24(1):136-147.