Nighttime Magnetic Field Exposure Linked to Reduction in Melatonin

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January 02, 2008 | 15,375 views

New evidence suggests that an increase in magnetic field strength in a woman's bedroom is associated with a reduction in melatonin production, according to a presentation at the American Cancer Society Science Writers Seminar. The study is part of a research effort exploring hypothetical links between melatonin, estrogen, and breast cancer. Dr. Scott Davis of the Fred Hutchinson Cancer Research Center in Seattle, Washington, says that this study helps bridge a gap in electromagnetic field research.

Animal experiments show that magnetic fields suppress melatonin production and accelerate the growth of breast tumors. And small epidemiologic studies indicate that very strong magnetic fields, such as those experienced by power line workers, may increase the risk of male breast cancer. Dr. Davis says that his work is "the first evidence in humans in a normal living environment, that would suggest that relatively small changes in magnetic fields do have an observable impact on lowering melatonin levels."

In a study funded by the Electric Power Research Institute, Dr. Davis and his colleagues measured magnetic field exposures of 199 women during a 3-day period, using portable magnetic field monitors worn during the day and stationary monitors that measured bedroom field and light exposure during the night. The women were also interviewed and kept diaries during the study period. These data were compared to the concentration of 6-sulphatoxymelatonin in urine collected during the night. The researchers controlled for age, alcohol use, body mass index, and medications that are known to affect melatonin levels.

Dr. Davis says that a doubling of nighttime magnetic field exposure is associated with an average melatonin production decrease of about 8%. Tripling the nighttime magnetic field is linked to a 15% reduction in melatonin production. Dr. Davis and his colleagues are now analyzing results from a parallel study of magnetic field exposure and breast cancer rates. If the patterns seen in this case-control study of breast cancer match those seen in the melatonin analysis, Dr. Davis and others say that the finding would strengthen the plausibility of a mechanism linking melatonin production to estrogen levels and thus breast cancer risk.

COMMENT: Melatonin is a very powerful hormone that can have profound effects on human physiology. That is why I rarely recommend it, even though it is available over the counter. It has been heavily promoted for its many benefits, including its powerful antioxidant and anti-cancer effects. However, I believe it probably works best when your own body produces it. There are limited occasions when melatonin supplementation is helpful. The two I can think of are when one goes through multiple time zones (especially travelling east) and is hit with jet lag and for shift workers. For most other people, I believe that melatonin supplementation risks outweigh the benefits. The converse situation, which may even be more harmful, are circumstances that deplete melatonin production. That is why EMF exposure can be so detrimental to health. It seems that EMF exposure has very clearly been documented now to decrease melatonin production. This can only lead to adverse health consequences. Issue #40 also reviewed some of the EMF issues.


One in three people in the US sleeps for 6 hours or less per night, substantially less than the recommended 8 hours, according to a new survey. Indeed, the average man and woman gets 7 hours of sleep a night, and a lack of sleep leads 37% of people to report daytime sleepiness severe enough to interfere with daily activities. That percentage increases to 52% for shift workers, according to the National Sleep Foundation (NSF) telephone survey of 1,027 people conducted in late 1997 and early 1998.

The report was released March 25 to launch National Sleep Awareness Week (March 30 to April 5). "People have no idea how important sleep is to their lives. Most of us need 8 hours of sound sleep to function at our best, and good health demands good sleep," said Roth, health and scientific advisor of NSF and director of the Sleep Disorders Research Center at Henry Ford Hospital in Detroit, Michigan.

The survey also found some popular misconceptions about sleep needs. For example, 42% of people believe that aging leads to a reduced need for sleep. But NSF experts say that while older adults may tend to waken more frequently during the night compared with their younger peers, the need for sleep does not decline with age.

The survey also showed that more than 70% of people believe the body can eventually adjust to working a night shift. But in fact, humans are "programmed" to feel most sleepy at night and most alert during daylight hours, according to the NSF. The survey also found that many people experience sleeping problems, including 43% who suffer from insomnia and a similar amount who snore.

And sleep deprivation can be hazardous to health. About 57% of men and women and 80% of evening- or shift-workers say they have driven while drowsy sometime in the past year, and 23% say they have actually fallen asleep while driving. About 1,500 people are killed annually by drivers who fall asleep at the wheel. More young people are killed every year by sleepy drivers than drunk drivers, according to the NSF.

COMMENT: Sleep is an essential nutrient that many of us short change. I have certainly been guilty of that in the past. However if you want to stay optimally healthy, it is wise to get at least 7 hours of sleep a night. Listen to your body, as many of us need much more than 7 hours, perhaps as much as 9 hours every night. Exercise is one of the best things one can do to restore normal sleeping patterns. It is the most effective antidote I know of for people who suffer with insomnia.