The normal daily rhythm of intense sunlight alternating with nights of near total darkness has dominated the planet for many thousands of years. We have altered this cycle recently with artificial light which can bombard city dwellers around-the-clock. This attempt to erase the night or at least confine it to small artificially confined windows may come with a price. At a minimum, it can lead to a chronic lack of sleep, diminishing the effectiveness of the body's immune system. Newer studies however show that it can also disrupt our melatonin levels and increase our risk of developing cancer.
Melatonin is secreted primarily in the brain and at night it triggers a host of biochemical activities, including a nocturnal reduction in the body's estrogen levels. Some researchers have speculated that chronically decreasing an individual's melatonin productions as with nighttime light might increase the risk of developing estrogen-related malignancies such as breast cancer. Melatonin also functions as one of the body's most powerful antioxidants.The first preliminary evidence linking light to cancer emerged 8 years ago in a report published by the CDC which showed that profoundly blind women had half the breast cancer risk of normally sighted women. Last month, the researcher updated the findings to show that the risk was actually 70% less in profoundly blind women. In women who had severe visual impairment but could still sense light, there was no difference in the breast cancer rate. Among profoundly blind men, the lower incidence of cancer showed up largely in cancers of the prostate, stomach, colon, rectum, skin and lung.
Studies are now underway to determine which wavelengths, or colors, are most biologically active. Blue and green appear especially effective at inhibiting melatonin production. Some colors inhibit production with as little as 5 lux of light which is a little more than what you'd have with full moonlight.
Science News October 17, 1998 154:248-250.
COMMENT: This is fascinating research that has many practical implications. It really tends to confirm Dr. Lee's earlier work which I mentioned in my September 20 newsletter. This research tends to validate that estrogen does indeed cause cancer. Fortunately, in addition to sleeping in complete darkness, we can also use natural progesterone to counter excessive estrogen. I have been using 5 mg twice a day now for the past month and am quite pleased with the results. I plan on continuing the regimen indefinitely. I would also caution everyone to sleep in complete darkness as much as possible. If you have street lights that shine through your windows, you would be best served by having some type of window treatment that will block nearly all the light coming through the window. I also now turn the clock radio upside down before I go to bed so the green LCD does not shine in the room. It will also be important to check any night lights you have and consider removing them and certainly to not turn on a light if you have to get up to go to the bathroom.