With the summer season coming upon us, spending time outdoors is a natural outcome of the warmer, sun-filled days. Without giving a second thought, many will reach for sunscreen to protect themselves from skin cancer. While these products are meant to provide our skin with a protective barrier to shield us from damaging our skin, could they be introducing other problems to our bodies that could potentially increase our risk for cancer, the very condition they’re supposed to protect us from?
If sun exposure is the cause of skin cancer, why are the rates of skin cancer in China–the world’s largest grower of food, and therefore the largest number of farmers who get plenty of sun exposure–so low, as compared to Denmark, whose citizens have a much lower sun exposure, but yet rank the highest in the world for skin cancer?
Could our beliefs about the dangers of the sun be unfounded? If so, what are the implications of using sunscreen? These creams or sprays are designed to block ultraviolet (UV) radiation from the sun, to which researchers claim exposure leads to skin cancer. However, these studies have all been done using only isolated UV light in the laboratory, which is different from the UV light from the sun. UV light from the sun is actually mixed with the other wavelengths in full spectrum sunlight. Therefore, the conclusions drawn from this research do not reflect the actual nature of sunshine.
While slathering sunscreen all over your skin may keep you from getting sunburned, an unintended consequence is that it will also prevent you from absorbing the energy derived from sunlight that is needed for your body to generate Vitamin D. Vitamin D is actually a hormone that is not only important in helping the body to absorb calcium and phosphorus, but, for those diagnosed with cancer, lab tests will typically show low levels of Vitamin D. So, spending time in the sun may actually be protective from the development of cancer, since that is one of the best ways to ensure that we are getting adequate levels of Vitamin D.
In addition to blocking out a much-needed source for Vitamin D generation, cancer prevention, and source of energy for all of life on earth, what else might you be concerned with regarding these ubiquitous summertime sun-blocking creams?
What lurks beneath the smooth, white lather of many of these creams are harmful chemicals that could lead to hormonal imbalances, which—you’ve guessed it—are implicated in cancer, especially those cancers that are hormonally sensitive.
Which sunscreen chemicals disrupt your hormones?
Oxybenzone is one of the most common, and proven to be the worst, UV filter used in sunscreens. This chemical has been proven to act as a hormone disruptor and to also cause allergic reactions in the skin. On EWG’s scale for toxicity, with zero being non-toxic, this chemical was rated high on the scale at an eight.[1]
In a 2018 published report by PubMed, the Centers for Disease Control and Prevention’s fourth national report on human exposure to environmental chemicals indicated that approximately “97% of the people tested have oxybenzone present in their urine, and independent scientists have reported various concentrations in waterways and fish worldwide.” [2] An additional Swiss study demonstrated that among the study participants, oxybenzone was found in the breast milk of 84% of the participants.[3] The presence of oxybenzone in breast milk may contribute to the fetal development of pregnant women as well as the development of breastfed children.
An endocrine disruptor, oxybenzone has been shown in animal studies to have estrogenic effects, which include developmental toxicity, reproductive toxicity, and uterine weight increase.[4] Along with these estrogenic effects, the chemical group in which this belongs, benzophenone (BP), has also been shown to “activate the proliferation of MCF-7 breast cancer cell and estrogen-responsive CHO (Chinese hamster ovary) cells at concentrations of the order of micromolar (a millionth of a mole—a quantity equal to 6.022 x 1023 atoms or molecules—which is a large number as this scientific notation means 6.022 with 23 decimal places) and lower.” [5] In addition to the estrogenic effects, BPs also interrupted the normal level of testosterone during the development of the animals tested in this study.
Octinoxate/Octylmethoxycinnamate (OMC) received the next lowest score on EWG’s ranking for toxicity. This cinnamate derivative not only disrupts the endocrine system, acting as estrogen in the body, it also affects the thyroid. An animal study published on PubMed.gov proved that exposure to OMC “caused a dose-dependent decrease of serum concentrations of TSH, T4 or T3 in rats.” [6] Although not conclusively proven, this study also states that exposure to OMC may have affected both the reproductive and neurological development of the offspring of rats exposed to OMC.
Homosalate was also found to disrupt estrogen, androgen, and progesterone by the EWG; however, according to a 2017 PubMed published study, homosalate had no effect on the endocrine system when tested on rats. Furthermore, homosalate was found in the breast milk in a study, which involved Swiss women. While some of this information seems to conflict, the main point is that homosalates can penetrate the skin. With this being the case, could homosalate possibly be affecting your hormones?
How do the mineral sunscreens affect your health?
Zinc Oxide and Titanium Dioxide are widely used in sunscreens. Because they tend to leave a thick, white film on the skin, some sunscreen manufacturers are leaning more towards the chemical alternatives for clear applications. Unlike chemical sunscreens, zinc oxide (ZnO) and titanium dioxide (TiO2) have less opportunity to penetrate the skin due to their thickness. However, this train of thought is debatable because the nanoparticles of these minerals are capable of penetrating the skin, depending on the size of the nanoparticle. Therefore, you may see non-nano (larger particle) versions of zinc oxide powder for sale that is often used in do-it-yourself sunscreens.
According to the EWG, a study conducted on whether or not skin penetration was possible with zinc oxide particles of 19 and 110 nanometers found that less than 0.01 percent of either form was found in the bloodstream. It was not evident if the trace amounts of zinc found were related to the sunscreen or zinc ions naturally found in the body. Because the amount was so minimal, it was concluded that the nanoparticles did not penetrate the skin.[7]
Aside from penetrating the skin, the nanoparticles of titanium dioxide and zinc oxide have been shown to cause health issues when inhaled, which can potentially occur with sunscreen sprays. In hepatocytes– liver cells, titanium dioxide nanoparticles have been shown to compromise the mitochondria of these cells, causing significant damage by changing the shape of the cells. According to a PLOS One published study, “exposure to TiO2 (titanium dioxide) nanoparticles, “even at a concentration as low as 50 ppm results in significant mitochondrial damage by interrupting the fusion-fission equilibrium and affecting the mitochondrial dynamics… TiO2 nanoparticles induced a strong oxidative stress in primary hepatocytes. TiO2 nanoparticles exposure also resulted in morphological changes in mitochondria and substantial loss in the fusion process, thus impairing the mitochondrial dynamics.”[8]
Another study concluded that titanium dioxide nanoparticles produced inflammation caused by the increased levels of mitochondrial reactive oxygen species (ROS).[9] With the onset of inflammation and the change in mitochondrial function induced by these nanoparticles, titanium dioxide may increase the risk of cancer. Therefore, if you, or someone you know, is dealing with cancer, it would be wise to avoid all sunscreens that contain this mineral.
One study shows that zinc oxide may indeed be capable of penetrating the skin. According to a 2011 study, zinc oxide nanoparticles are “internalized by the human epidermal keratinocytes [cells in the outermost layer of the skin that produces a protein, keratin] and elicit a cytotoxic and genotoxic response.”[10] This means that zinc oxide is toxic to cells and genes.
In another study, it was determined that zinc oxide can release pro-inflammatory cytokines, which results in inflammation. This study concluded, zinc oxide nanoparticles can have potentially detrimental effects on cells “even at dosages where there are little or no observable cytotoxic effects.”[11]
Titanium dioxide and zinc oxide are shown as low in toxicity on the EWG scale. However, these ingredients cannot be deemed safe for use.
How do you reap the benefits of the sun safely?
Gradually condition your skin for increased sun exposure. Try not to spend an excessive amount of time in the sun, especially if it’s the first day that you’re spending outdoors after mostly being indoors. Limit your time initially, and gradually increase the time in such a way that you will not receive a sunburn. If you have particularly fair skin, you may want to limit your time outside between 10 am and 2 pm.
Spend time in the early morning and late afternoon sunshine. Make it a point to spend time just after the sun rises. Having both UVA and UVB present, along with the other parts of the spectrum like the infrared energies from the sun helps to normalize your circadian rhythm, by regulating key hormones, such as melatonin. Spending time outdoors in the late afternoon sun can also bring you the healing rays from the infrared spectrum of the rays from the sun.
Stay hydrated. Your body is comprised mostly of water. By staying hydrated, your skin’s moisture content increases, which decreases the risk of skin damage and dehydration in the sun.
Create your own natural sunscreen. Using ingredients from the list below, you can create your own natural sunscreen without the use of harmful chemicals found in over-the-counter remedies. Essential oils such as lavender, tea tree oil, helichrysum, and peppermint oil can be used to enhance the benefits of your creation. Use either coconut oil or olive oil as the carrier oil, to which you mix another oil, for example, carrot seed oil. After your mixture is complete, it’s best to store it in a cool dry area to prolong its shelf-life. When you’re ready to use it, be sure to apply it liberally to exposed skin every two hours that you’re out in the sun.
We’re all going to spend extra time outside in the sun during these warmer months. Rather than being fearful of the sun, being informed and putting some simple measures into practice, you can have your fun in the sun while creating the life that you love and living in health.
What are some of your favorite sunning tips that you think may help other readers? Please share it in the comments below.
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References:
[1] (n.d.). The Trouble with Ingredients in Sunscreens – EWG. Retrieved June 4, 2018 from https://www.ewg.org/sunscreen/report/the-trouble-with-sunscreen-chemicals/#.WxWDvHovxPZ
[2] DiNardo, J.; Downs, C. (February 2018). Dermatological and environmental toxicological impact of the sunscreen ingredient oxybenzone/benzophenone-3 – PubMed.gov. Retrieved June 4, 2018 from https://www.ncbi.nlm.nih.gov/pubmed/29086472
[3] Krause, M.; Klit, A.; Blomberg, J.; Søeborg, T.; Frederiksen, H.; Schlumpf, M.; Lichtensteiger, W.; Skakkebaek, NE.; Drzewiecki, KT. (June 2012). Sunscreens: are they beneficial for health? An overview of endocrine disrupting properties of UV-filters – Pubed.gov. Retrieved June 4, 2018 from https://www.ncbi.nlm.nih.gov/pubmed/22612478
[4] Wang, J.; Pan, L.; Wu, S.; Lu, L.; Xu, Y.; Zhu, Y.; Guo, M.; Zhuang, S. (August 3, 2016). Recent Advances on Endocrine Disrupting Effects of UV Filters – PubMed.gov. Retrieved June 4, 2018 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997468/.
[5] Wang, J.; Pan, L.; Wu, S.; Lu, L.; Xu, Y.; Zhu, Y.; Guo, M.; Zhuang, S. (August 3, 2016). Recent Advances on Endocrine Disrupting Effects of UV Filters – PubMed.gov. Retrieved June 4, 2018 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997468/.
[6] Wang, J.; Pan, L.; Wu, S.; Lu, L.; Xu, Y.; Zhu, Y.; Guo, M.; Zhuang, S. (August 3, 2016). Recent Advances on Endocrine Disrupting Effects of UV Filters – PubMed.gov. Retrieved June 4, 2018 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4997468/.
[7] (n.d.). Nanoparticles in Sunscreens – EWG. Retrieved June 4, 2018 from https://www.ewg.org/sunscreen/report/nanoparticles-in-sunscreen/#.WxVJfHovxPY
[8] Vaishaali Natarajan, V.; Wilson, C.; Hayward, S.; Kidambi, S. (August 6, 2015). Titanium Dioxide Nanoparticles Trigger Loss of Function and Perturbation of Mitochondrial Dynamics in Primary Hepatocytes – Plos One. Retrieved June 4, 2018 from http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0134541
[9] Qun Chen, O.; Wang,N.; Zhu, M.; Lu, J.; Zhong, H.; Xue, X.; Guo, S.; Li, M.; Wei, X.; Tao, Y.; Yina,H. (May 2018). TiO2 nanoparticles cause mitochondrial dysfunction, activate inflammatory responses, and attenuate phagocytosis in macrophages: A proteomic and metabolomic insight – PubMed.gov. Retrieved June 4, 2018 from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5752088/
[10] Sharma, V; Singh, S.; Anderson, D; Tobin, D; Dhawan, A. (May 2011). Zinc oxide nanoparticle induced genotoxicity in primary human epidermal keratinocytes – PubMed. Retrieved June 4, 2018 from https://www.ncbi.nlm.nih.gov/pubmed/21780369
[11] Heng, B.; Zhao, X.; Tan, E.; Khamis, N.; Assodani, A.; Xiong, S.; Ruedl, C.; Ng, K.; Loo, J. (December 2011). Evaluation of the cytotoxic and inflammatory potential of differentially shaped zinc oxide nanoparticles – PubMed. Retrieved June 4, 2019 from https://www.ncbi.nlm.nih.gov/pubmed/21656222
[12] Katie. (May 8, 2018). Natural Homemade Sunscreen – Wellness Mama. Retrieved June 4, 2018 from https://wellnessmama.com/2558/homemade-sunscreen/
[13] Jenkins, N. (October 14, 2011). Carrier oils and SPF – Natural therapy Pages. Retrieved June 4, 2018 from https://www.naturaltherapypages.com.au/article/carrier_oils_and_spf
