Night Light Cancer

[GAF]

Apparently light a night can cause breast and prostate cancer. Can one of you scientist types shed some light on this study? Thanks for your assistance.

Conclusions
Findings from this large case–control study of two cancers that
have been associated with circadian disruption and light at
night during shift work provide some support for the influence
of ALAN for the development of cancer in the general popula-
tion. Men who reported the highest level of exposure to indoor
ALAN were at greater risk of prostate cancer than men who
reported no indoor illumination at night. Although both cancers
were less likely among those in the highest versus lowest tertile
of exposure to outdoor ALAN in the visible spectrum, outdoor
ALAN in the blue-light spectrum, which is believed to be the
most biologically relevant exposure, was positively associated
with prostate cancer and, to a lesser extent, with breast cancer.

 

[shepherdgirl]

I seem to recall Peat saying that darkness increases prolactin, and he also may have said that sleeping with the light on could be good in some cases. So far I can't find the quote though.

 

[shepherdgirl]

Here is something along those lines:

Melatonin and prolactin are induced by stress, and darkness is a stress because it impairs mitochondrial energy production.

Ray Peat, Aging Eyes, Infant Eyes, and Excitable Tissues

I wonder what Dr. Peat would think about sleeping in red light.

 

[SOMO]

I can't imagine we're adapted to sleeping in any significant amount of light.

I imagine many people slept by fires throughout human history and that might have created an adaptation to dim light at night. But if you're sleeping with your computer monitor on all night, or the overhead lights or a bright lamp on, it will eventually **** up your sleep schedule and circadian rhythm. Kind of like how eating too late at night/too close to bed can make you feel bloated in the morning.

I don't have issues falling asleep with the lights on, but it feels more "natural" to sleep in complete darkness.

 

[shepherdgirl]

Well I pretty much agree with you @SOMO - blue light from computers does not seem like a good idea to me either. Where there are seasonal variations in the length of the day, though, you tend to find animals that hibernate in the dark months. According to Peat:

Serotonin and its derivative, melatonin, are both involved in the biology of torpor and hibernation.

Ray Peat, Serotonin, depression, and aggression: The problem of brain energy
IIRC he also mentioned somewhere that bears become diabetic over the winter - not sure how much of that would be due to darkness versus a lack of carbs and the necessity of using pufas in body fat in cold climates.

 

[smith]

eating too late at night/too close to bed can make you feel bloated in the morning

well of course, digestion slows down and sometimes stops completely while unconscious, which is why some people sleep better with an empty stomach. ...Right guys? ..right?

 

[dmoon]

There are actually quite a few studies showing the link between light at night and increased risk of breast, prostate, and colon cancer. The World Health Organization added artificial light at night to its list of probable carcinogens in 2007.

I wrote an article on it recently: How light at night could double your risk of cancer. with references to many studies on the topic. Artificial light at night not only disrupts the core circadian genes, but it also decreases melatonin production, which is thought to act as an antioxidant. The epidemiological studies for light at night (either from night shift work or looking at areas with lots of street lights vs dark areas) show an increased risk of breast cancer -- anywhere from 34% to over 2x. There are lots of mouse studies showing the impact of light at night as well.

When looking into the effects of disrupting circadian rhythm -- either through dim light at night or by blue wavelengths from screen, LED/CLF bulbs, etc -- there is actually a ton of research showing that we are really screwing ourselves up. Circadian disruption increases the risk of obesity, diabetes, heart disease, Alzheimer's, and certain cancers.