Artificial light has become the main source of light exposure for a huge portion of the world, especially in developed countries like the U.S. And the spectrum of light that’s now taking center stage in our lighting choices, electronics and more is blue light.
Sadly, the negative impact that blue light has on our health has been slowly coming to light…
You see, blue light is high-energy visible light (HEV) and is different from the UV (ultraviolet light) that comes from the sun.
While blue light encompasses wavelengths of 400 nm to 500 nm, UV light rings in from 100 nm to 400 nm. And though blue light is capable of reaching the retina of your eye, UV light is blocked from entering your eye by your cornea and crystalline lens.
This means that while UV light can do surface damage if you’re exposed for too long of time periods (think that nasty sunburn from a day at the beach), blue light with its deep penetration can impact your health below the surface.
In fact, studies have found associations between nighttime exposure to artificial light — especially blue light — and numerous health problems ranging from sleep disorders and obesity to an increased risk of various types of cancer, especially in night-shift workers.
Now, blue light from artificial light sources has another dangerous issue chalked up in its column — colorectal cancer.
Outdoor lighting at night and your cancer risk
A team of researchers led by the Barcelona Institute for Global Health (ISGlobal) recently conducted the first study analyzing the association between nighttime exposure to outdoor artificial light and colorectal cancer. And their findings, published in Epidemiology, are going to make you want to purchase blackout curtains.
The scientists combed through data on approximately 2,000 adults in Barcelona and Madrid. And just to make it fair and eliminate any confounding issues that could contaminate the results, they excluded data for night-shift workers, since night shift work is already linked to colon cancer. They then estimated each person’s probable nighttime exposure to outdoor artificial light based on images from the International Space Station (ISS).
And here’s where it gets scary…
Results from both cities showed that participants with the highest exposures to outdoor blue light had a whopping 60 percent higher risk of developing colorectal cancer than those with less blue light exposure.
How frightening is that? Just being exposed to more light in the blue light spectrum during the nighttime hours caused the risk of colorectal cancer to skyrocket.
The team found no such association between full-spectrum light and colon cancer.
The melatonin connection
But how does this work? Why would blue light exposure lead to colon cancer?
The researchers explained it this way…
“Nighttime exposure to light, especially blue-spectrum light, can decrease the production and secretion of melatonin, depending on the intensity and wavelength of the light.”
That’s important since melatonin has been found in previous studies to inhibit colon cancer migration and metastasis and to have “anticancer activity,” which makes it easy to see why if you blocked melatonin, colorectal cancer could be the result.
This makes it vital then to eliminate as much blue light exposure at night as possible. While you may not have control of the lighting you’re exposed to outside that comes from street lights and commercial billboards, if you want to avoid upping your risk for colon cancer, start decreasing your exposure from other sources of blue light, like white LEDs and tablet and phone screens.
This means that you should choose light bulbs with a warm tone, limit screen time at night and install blue light filtering apps to help.
Could supplements help? Melatonin has a safe reputation as a sleep aid and if blue light exposure decreases the body’s natural production, it’s certainly worth considering.
Additionally, some eye health supplements, like Peak Vision Support™, contain special formulations of lutein and zeaxanthin that protect eyes against blue light damage.
The Role of Melatonin in Colorectal Cancer — Springer Link
Tips to Reduce Hazard of Blue Light — YourSightMatters.com