We all know how important it is to protect our skin in the sun. Especially when we are exposed to the UV rays for long hours. By protecting our skin we are also protecting our health. We should be applying sunscreen every day, all year around, when we are outside. The UV rays come through clouds, rainy days as well as in snowy parts of our world.
However, women and men who use certain sunscreens might be at risk of infertility. Scientists found 45% of the ingredients contained chemicals can interact with the function of sperm. It is important to remember that research is still ongoing. In one study tests were made in vitro, using sperm cells in a solution that mimicked conditions inside the female fallopian tubes.
Skakkebaek and colleagues studied 29 of the 31 UV filters allowed in sunscreen in the U.S. or the European Union (EU) on live sperm cells collected from healthy donors. The cells were placed in a buffer solution.
The analysis was focused on calcium signaling, where changes in the concentrations of calcium ions causes the cell to behave differently. In sperm, this signaling is very important. CatSper is one of the most important calcium ion channels inside the human sperm cell. It’s the main receptor for progesterone, a hormone that attracts human sperm cells. When the hormone binds to the CatSper calcium channel the interaction causes a temporary surge in calcium ions inside the sperm cell. This controls several sperm functions necessary for fertilization.
Researchers found 13 of 29 tested UV filters induced calcium ion influxes in the sperm cell. “This effect began at very low doses of the chemicals, below the levels of some UV filters found in people after whole-body application of sunscreens,” Skakkebaek said. Nine of the thirteen filters specifically caused calcium ion influx in the CatSper channel, thereby mimicking the effect of progesterone.
Dr. Skakkebaek, also said that UV filters are used in sunscreens that protect the body by absorbing UV rays, instead of reflecting them. Physical sunscreens that contain reflecting chemicals like zinc shouldn’t interfere with sperm function – if there’s anything that’s interfering in the first place. We’ll know more for certain after further research on mice is carried out.
Some of the filters found to disrupt sperm function are: avobenzone, homosalate, meradimate, octisalate (also known as octyl salicylate), octionxate (or octyl methoxycinnamate, octocrylene, oxbenzone (also called benzophenone – 3 or PB-3) andpadimate O.
Niels Skakkebaek, MD, DMSc, is a professor at the University of Copenhagen and a researcher at the Copenhagen University Hospital, Rigshospitalet.
Titanium dioxide and zinc oxide seem to be the most effective and doesn’t penetrate through the skin. Both of these are considered to be a nanoparticles. Zinc oxide is stable in sunlight and can provide greater protections from UVA rays than titanium oxide. A chart shown on the www.ewg.org site indicates that avobenzone has very limited skin penetration. Yet Dr. Skakkebaek found that this ingredient is a disruptor of sperm. And avobenzone has a relatively high rate of skin allergies.
Nearly every chemical sunscreen in the United States contains avobenzone because it is the best available agent for filtering skin-damaging UVA rays. Avobenzone alone may break down when exposed to sunlight and must be stabilized with other chemicals such as octocrylene.
Our sunscreens must provide protection from the suns damaging cancer causing rays, but most are known to permeate the skin to some degree.
BUT WHAT ARE UV RAYS?
Ultraviolet radiation is part of the electromagnetic (light) spectrum that reaches the earth from the sun. It has wavelengths shorter than visible light, making it invisible to the naked eye. These wavelengths are classified as UVA, UVB, or UVC, with UVA having the longest of the three at 320-400 nanometers (NM, or billionths of a meter). UVA wavelengths penetrates most deeply. UVA is the most damaging and contributes to photo aging. Which produces skin deterioration and melanomas in fair-skinned people. Which is my case. I had a melanoma 8 years ago. Caught early and it didn’t spread made it curable. But melanomas are determined within us early in life with major sun exposure.
UVA and UVB rays, however, penetrate the atmosphere and play an important role in conditions such as premature skin aging, eye damage (including cataracts), and skin cancers. They also suppress the immune system, reducing your ability to fight off these and other maladies.
By damaging the skin’s cellular DNA, excessive UV radiation produces genetic mutations that than lead to skin cancers. But the U.S. Department of Health and Human Services and the World Health Organization have identified UV as a proven human carcinogen. UV radiation is considered the main cause of skin cancers including basal cell carcinoma and squamous cell carcinoma. These cancers strike more than a million and more than 250,000 Americans each year. When left untreated, melanomas are the deadliest form of skin cancer, which kills more than 8,000 Americans each year.
UVB, the chief cause of skin reddening and sunburn, tends to damage the skin’s more superficial epidermal layers. It plays a key role in the development of skin cancer and a contributory role in tanning and photo aging. Its intensity varies by season, location and time of day. The most significant amount of UVB hits the U.S. between 10 AM and 4 PM from April to October. However, UVB rays can burn and damage your skin all year long, especially at high altitudes and on reflective surfaces such as snow or ice, which bounce back up to 80 percent of the rays so that they hit the skin twice. UVB rays do not significantly penetrate glass.
There are clothing companies that sell sun protected clothing. I am not sure how many washes this type of clothing can go through before the protection is gone, but always wear a hat, sunscreen and long sleeves if outside for long periods of time. Reapply a good quality sunscreen often.
Advice from the American Academy of Dermatology for anyone spending time outdoors is to apply 1 ounce of a broad-spectrum sunscreen with a sun protection factor (SPF) of 15 or higher 15 minutes before exposure and reapply every 2 hours. But what does broad-spectrum mean?
A broad-spectrum sunscreen is a mix of several chemicals that protect against both UVA and UVB radiation. Using a broad-spectrum sunscreen is important because it is the only way to know that you are being protected from both rays.
Not all sunglasses will protect you. Sun and light filters through the sides and top part of the glasses. Sunglasses should have lenses large enough to keep the sun out of the eyes from all angles, and they should be rated to block 99% to 100% of both UVA and UVB rays. It is also important that they have a nosepiece that will resist slippage when the skin gets sweaty. These factors should be applied to choosing glasses for young children as well.
There is no rating for the effectiveness of sunscreen at blocking UVA radiation. The SPF is a measure of the product’s effectiveness to prevent sunburn caused only by UVB rays. The SPF is a multiple of the time it takes for a person to get sunburn. If you would normally burn in 10 minutes, an SPF or 15 should extend the time it takes to burn by 15 times, or 150 minutes.
A rating of SPF 15 filters 93% of UVB rays, SPF 30 filters 97% of UVB rays, SPF 50 filters 98% of UVB rays.
The U.S. Food and Drug Administration (FDA) defines the term water resistant as maintaining its SPF while wet for 40 minutes. They define very water resistant as maintaining SPF for 80 minutes while wet. Labeling laws on sunscreen packaging require the manufacturer to disclose this information. There is no such thing as waterproof or sweat proof sunscreen and the FDA banned the use of these terms in 2013.
REFERENCES
The Trouble with Sunscreen Chemicals – http://www.ewg.org.
Half of Sunscreens Might Disrupt Sperm Function – http://zmescience.com/medicine/sunscreen-sperm-function.
Some Sunscreen Ingredients May Disrupt Sperm Cell Function. – http://endocrine.org/news-room/current-press-releases/some sunscreen-ingredients-may-disrupt-sperm-cell-function.
Sunscreens (UV Filters) – http://breastcancerfun.org/clear-science/radiation-chemicals-andbreastcancer/sunscreens-uv-filters.
How to Choose the Right Sunscreens for Your Skin Type – http://TheSkinCancerFoundation. 149 Madison Avenue, Suite 901, New York, New York 10016
UVA & UVB – http://TheSkinCancerFoundation. Address is above.
Sun Exposure and Exercise The Good, The Bad, and the Behavior Change – Jeff Lynn, Ph.D.; Joyan Urda, Ph.D.; and Patricia Pierce, Ph.D., FACSM. ACSM Health and Fitness Journal. Volume 20, Number 3, May/June 2016. www.acsm-healthfitness.org.
Centers for Disease Control and Prevention.
U.S. Food and Drug Administration, FDA
American Academy of Dermatology
