Blue light exposure and colorectal cancer, what do you think linking the two may have? Well, when you go to bed at night, do you actually go to bed, or do you sit in front of your phone or tablet scrolling through your news feed, answering emails and getting lost on social media? How often do you take your computer to bed to work? All of these things expose you to blue light. It has been found to promote eye strain and damage retinal cells. But this is just the tip of the iceberg, as researchers have now discovered a strong link between blue light exposure and colorectal cancer.
Outdoor Blue Light Exposure At Night Is Linked To Cancer
Scientists have found a direct link between the amount of blue light illuminating homes at night and the rate of colorectal cancer. The study involved 661 people living in two Spanish cities, Madrid and Barcelona, who had been diagnosed with colorectal cancer between 2007 and 2013. This group was compared with a group of 1322 people who had no history of cancer and were matched to the study group by sex and age.
Data Collection
Images taken from the International Space Station provided access to the type of nighttime outdoor artificial light exposure in the red, green, and blue spectrums to which the study participants were subjected. Data on where the participants lived and worked, as well as other cancer risk factors such as age, body mass index, family history of cancer, lifestyle habits such as alcohol consumption, smoking, exercise, diet and sleep were collected, as well as their education and socioeconomic status. People with cancer were on average 67 years old and were more likely to have a family history of cance
Previous Studies Have Shown A Link Between Blue Light Exposure And Cancer
According to study co-author Manolis Kogevinas, scientific director of the Servo Ochoa Distinction at the Institute of Global Health in Barcelona, the research team wanted to build on several other studies that have linked night work and light, which interfere with our internal body clock or circadian rhythm. Links have previously been found between blue light and breast and prostate cancers.
Hormones And Circadian Rhythm
In a study published in the Journal of Epidemiology, researchers pointed out that circadian rhythms are very closely linked to hormones. It is thought that exposure to blue light at night may alter the production of certain types of chemicals. This information is supported by previous links to circadian rhythm disruption and colon cancer noted in animal studies.
Exposure to artificial light at night can cause depression and delay the release of melatonin, a hormone linked to tumor growth and made during the dark phase of the body's 24-hour cycle.
Not Quite Granular Enough
Kogevinas said the study was somewhat limited because it was not possible to accurately measure the amount of light reaching people's homes.
"I would have liked to have had a few thousand people wear a personal light sensor for a few years! That would have given a much more accurate estimate of light. We accurately measure ambient light and especially blue light, but we don't really measure what reaches the person's eyes."
However, the researchers found that light exposure at night is not a neutral factor for health and well-being. In fact, it is something that should be taken seriously. The body needs time in the dark, and even a period of complete darkness. When the body is disconnected from its internal clock and out of sync with its normal rhythm, the impact is not insignificant.
What About Computers, Tablets And Phones?
While the latest research does not specifically address blue light produced by computers, phones and tablets, the researchers did make a connection and recommendation.
"Exposing ourselves to unnecessary levels of light, and in particular blue light, is not recommended. Yet some of the blue light exposure comes from tablets and smartphones. Companies should further develop their technologies to further reduce light emissions."
So the takeaway is that if you get a lot of light through your bedroom window, install curtains or blinds and keep them closed at night. If you have a habit of taking your phone to bed, stop immediately. Leave your phone outside your room, where you won't be tempted to pick it up during the night. And, stop working in bed! When it's time to sleep, honor your body and give it what it needs to be healthy. Rest is key, and exposure to blue light interferes with your body's natural ability to heal and replenish itself.
