The onset of summer brings renewed warnings from some corners of social media that sunglasses should be avoided as they can reduce the body鈥檚 ability to resist harmful ultraviolet radiation (UV rays). This is false. Also, warnings to avoid wearing sunglasses serve a doubly dangerous message as sunglasses with UV protection help shield eyes from UV rays that could eventually cause cataracts or skin cancer.
As recently as June 7, health advocate, podcaster and self-described "biohacker" Noah Ryan posted on : 鈥淒on't wear sunglasses. Melanin protects your skin from UV radiation. More melanin = less risk of DNA damage. The signaling molecule for melanin (melanocyte-stimulating hormone) is produced in the pituitary gland. The pituitary gland determines how much MSH to make based on signals from your eyes. The stronger the light, the more melanin produced. Wearing sunglasses dampens this response, resulting in less melanin production. Less melanin = more sunburn. Wear a visor instead. Less sun on your face but you still get refractory rays.鈥
The tweet had more than 115,000 views.
Similar claims can be found on , and .
Rating: False
The medical consensus is there is no proof of such a direct link between sunglasses and an increase in sunburns and their potentially malignant consequences, and when it comes to melanin production, there is far more than, well, meets the eye.
The , the prestigious U.S.-based academic medical centre, says melanin is a complex polymer that absorbs UV rays to protect cells from sun damage. It is produced in melanocytes located throughout the body, including hair, skin, pupils and irises, areas of the adrenal gland, the brain and inner ear.
鈥淲hen you spend time out in the sun, your body produces more melanin," says a post on the clinic's website. "The substance absorbs light from UV rays and redistributes it toward the upper layers of skin. It also protects the genetic material stored in your cells by keeping out harmful UV rays. But keep in mind that melanin alone isn鈥檛 enough to protect your skin from sun damage. That鈥檚 why it鈥檚 so important to wear sunscreen and appropriate clothing whenever you鈥檙e outside.鈥
The U.S. government鈥檚 鈥 its lead agency for cancer research and training 鈥 states melanocytes are contained in the innermost layer of the skin called the basal layer, adding, 鈥淪un exposure causes melanocytes to increase production of melanin in order to protect the skin from damaging ultraviolet rays, producing a suntan.鈥
The states: 鈥淥nce skin is exposed to UV radiation, it increases the production of melanin in an attempt to protect the skin from further damage.鈥
None of these agencies says sunglasses prevent melanin production.
Ophthalmologist Deepti Mehta, working in Hyderabad, India, in an last month, says, 鈥淚t is a myth that wearing sunglasses can cause sunburns; this is not supported by any scientific evidence."
"Melanin production is primarily regulated by genetic factors and UV exposure, rather than the presence or absence of sunglasses.鈥
The sunglasses-sunburn theory was also recently fact-checked and by Dr. Fergus Brown from the United Kingdom and the London-based Full Fact fact-checking organization
Further to this, government agencies and research hospitals and authorities worldwide all recommend wearing sunglasses, primarily to prevent damage to the eyes, but none cites any concern or evidence that this protection could offset melanin production.
These agencies include , , the , the United Kingdom鈥檚 and the .
Social media posts claiming there is a link between sunglasses and sunburns point to research papers such as a 2003 report by the and a 2013 report in the journal
Both reports found UV-B irradiation of the eyes in mice increased the concentration of melanocyte-stimulating hormones, but as the 2003 study shows, irradiating other areas of the body produced melanocytes as well.
In addition, the 2013 report states 鈥渢he use of a sunscreen and/or sunglasses that eliminates UV is recommended both to protect the skin and to prevent pigmentation, particularly in an area exposed to strong sunlight.鈥
Sources
Claim can be found on Twitter () and (), on Instagram (, ) and on health and fitness blog Tom Nikkola ()
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