How Safe is Your Sun Safety?
Repeated exposure to the sun’s UVA and UVB rays is directly correlated to up to 90% of skin cancers and with our hot Aussie summer approaching, skin care is highly essential. In addition to increasing cancer risk, UV rays contribute to premature skin ageing and sun damage. Understanding that our body absorbs up to 85% of what we put on it, it’s important to make a conscious decision of what you lather on your skin this summer.
The skin is the largest organ of the body and is responsible for one-quarter of the body’s elimination capacity.
For this reason, the skin is also known as the ‘third kidney’. Unlike other body systems, the skin immediately absorbs all the ingredients in skin care products that we lather on our skin. As such, the chemicals directly reach the bloodstream and the body doesn’t have the ability to detoxify them prior to absorption. Thus, the ingredients in your sunscreen must not be irritating or cause skin allergies; similarly, they should be able to withstand powerful UV radiation without losing their effectiveness or forming potentially harmful breakdown products.
What to look for in sunscreens
The active ingredients in sunscreens come in two forms – mineral and chemical filters. Each uses a different mechanism for protecting skin and maintaining stability in sunlight. The most common sunscreens on the market contain chemical filters. These products typically include a combination of two to six of the following active ingredients:
- oxybenzone
- avobenzone
- octisalate
- octocrylene
- homosalate
- octinoxate
Mineral sunscreens use zinc oxide and/or titanium dioxide. A handful of products combine zinc oxide with chemical filters. Knowing which one you are purchasing and applying is important when we are looking at endocrine health and potential environmental endocrine disruptors.
Chemical UV filters in sunscreens and how they affect hormones
Laboratory studies indicate that some chemical UV filters may mimic hormones and physicians report sunscreen-related skin allergies, raising important questions about unintended human health consequences from frequent sunscreen application. Some UV chemical filtering sunscreens have been suggested to impair fertility in males. Specifically, they reduce sperm count via the ability of chemicals to activate calcium ion channel signalling by mimicking the hormone progesterone.
Chemical sunscreens vs mineral sunscreens
Chemical sunscreens commonly include ingredients that act as “penetration enhancers” which help the product adhere to the skin. This gives the more aesthetically pleasing look of the sunscreen as it tends to be thinner and therefore, spreads more easily on the skin. As a result, many sunscreen chemicals are absorbed into the body and can be measured in blood, breast milk and urine samples.
Mineral sunscreens are made with zinc oxide and titanium dioxide. One of the main drawbacks of natural mineral sunscreens is that they tend to leave the white residue on the skin. This is due to the mineral particles. The more aesthetically favourable formulations have micronized these mineral particles to minimise the white cast. They are not absorbed by the skin (unless in nanoparticle form) and therefore, do not cause reactions. There is good evidence that little (if any) zinc or titanium particles penetrate the skin to reach living tissues. Thus, mineral sunscreens tend to rate better than chemical sunscreens.
Why opt for mineral sunscreens?
Using mineral-based sunscreens minimises our exposure to EDCs in skin care products and helps promote better skin health. Don’t forget to use all forms of sun safety as well. Covering yourself with sun-smart clothing and a hat is another great strategy. If you are spending prolonged time in the sun, it is also a smart idea to invest in a good-quality beach umbrella.
There’s really no need to be scared of the sun – just be sun-smart and sun-safe!
REFERENCES
Ananthaswamy H. N. (2001). Sunlight and Skin Cancer. Journal of biomedicine & biotechnology, 1(2), 49.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC113773/
Boas, M., Feldt-Rasmussen, U., & Main, K. M. (2012). Thyroid effects of endocrine disrupting chemicals. Molecular and cellular endocrinology, 355(2), 240–248.
https://pubmed.ncbi.nlm.nih.gov/21939731/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5751186/
Rehfeld et al. (2018). EDC IMPACT: Chemical UV filters can affect human sperm function in a progesterone-like manner. Endocrine connections, 7(1), 16–25.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5744631/
