By: Jean Johnson for Fibroids1“Early to bed, early to rise…” Breast cancer might not have been on Benjamin Franklin’s mind when he penned this line, but modern researchers are connecting the dots between a good night’s sleep – in a dark room – and a lower risk for breast cancer.
| Take Action |
Four ways to help your body maintain adequate levels of melatonin:
Sleep in a room that is completely dark
Get nine hours of sleep each night
If you use a night light, install a red bulb
Avoid turning the light on at night, even for brief periods |
Only in complete darkness does the body produce sufficient levels of serotonin, which is the neurotransmitter critical to melatonin production. In turn, recent research suggests that adequate melatonin levels are related to the body’s ability to deter cancerous tumors.
The study is preliminary, given its use of laboratory mice and rats. Nonetheless, between the human breast cancer cells and human blood samples used for the experiment, researchers have labeled the results compelling. After implanting breast cancer cells in mice, researchers collected three samples of blood from each of 12 healthy female volunteers. The samples were obtained during the daytime, at nighttime following two hours of complete darkness, and during the night following 90 minutes of exposure to bright fluorescent light. They were then pumped into the tumors and monitored.
“The melatonin-rich blood collected from subjects while in total darkness severely slowed the growth of the tumors,” said David Blask, MD, PhD, a neuroendocrinologist with the Bassett Research Institute and lead author of the study. “These results are due to a direct effect of the melatonin on the cancer cells. The melatonin is clearly suppressing tumor development and growth.”
Conversely, Blask added that tumors infused with melatonin-depleted blood from volunteers exposed to artificial light underwent rapid growth. That’s because, he explained, tumors tend to be “largely dependent on a nutrient called linoleic acid, an essential fatty acid, in order to grow.” Melatonin enters the equation by interfering with the “tumor’s ability to use linoleic acid as a growth signal, which causes tumor metabolism and growth activity to shut down.”
Artificial Night Light = Decreased Melatonin Levels = Elevated Rates of Breast Cancer?
The possibility that the bright lights of the big city can go to more than our heads has folks all over the map taking notice. Indeed, with breast cancer striking one in 10 women in the developed world, leaders are eager to identify potential causes.
“The risk of developing breast cancer is about five times higher in industrialized nations than it is in underdeveloped countries,” said Les Reinlib, PhD, program administrator with the National Institutes of Environmental Health Sciences (NIEHS). “These results suggest that the increasing nighttime use of electric lighting, both at home and in the workplace, may be a significant factor.”
NIEHS director, David A. Schwartz, MD, was equally interested in the study – and equally cautious in his remarks on its implications. “This is the first experimental evidence that artificial light plays an integral role in the growth of human breast cancer,” he noted. “This finding will enable scientists to develop new strategies for evaluating the effects of light and other environmental factors on cancer growth.”
Blask, as well, underscores that his preliminary data need further study in human subjects. He is still hopeful, however, that should the science prove accurate, society can adopt changes in the way it lights the night environment.
“If the link between light exposure and cancer risk can be confirmed, it could have an immediate impact on the production and use of artificial lighting in this country,” he said. “This might include lighting with a wavelength and intensity that does not disrupt melatonin levels and internal timekeeping. Evidence is emerging that disruption of one’s circadian clock is associated with cancer in humans, and that interference with internal timekeeping can tip the balance in favor of tumor development.”
In sum, Franklin seemed to be onto something with his early to bed idea. “The effects we are seeing are of greatest concern to people who routinely stay in a lighted environment during times when they would prefer to be sleeping,” said Mark Rollag, PhD, visiting research scientist at the University of Virginia and one of the study co-authors. “This is because melatonin concentrations are not elevated during a person’s normal waking hours.”
