(NaturalNews) A Vanderbilt University study suggests that artificial lights -- like those used in most hospitals -- may throw of the biological clocks of premature infants, which could put them at a greater risk of mood disorders such as depression as well as other hormone-related health problems.
The researchers analyzed the "master biological clock" in the brains of baby mice, located in an area of the brain called the suprachiasmatic nuclei (SCN), and theorized that constant exposure to light prevents the clock from developing properly. Because of this, the scientists suggest that hospital wards specializing in premature infants should try to minimize this exposure through the use of a day/night cycle.
In addition to the brain, the SCN influences the activity of a host of organs including the heart, liver and lungs, and it also regulates circadian rhythms; the body's daily activity cycles. The activity of the special "clock neurons" in the SCN are usually synchronized with the 24-hour day/night cycle, but the SCN neurons in adult mice exposed to constant light for about five months could not maintain coherent rhythms. The neurons in baby mice were even more vulnerable to the light.
The researchers tracked the mice's neurons by genetically modifying them to glow brightly when active, and found that, when the mice were exposed to a regular day/night cycle, their neurons quickly fell back into synchronicity. Also, newborn mice that were exposed to a regular day/night cycle during their first three weeks of life were found to be less susceptible to the effects of constant light when later exposed.
Lead researcher Dr. Douglas McMahon said the results were speculative at this point, and more work was needed to prove whether or not the risk of mood disorders could be linked to babies' biological clock, but he said that the data indicated human infants would benefit from "the synchronizing effects of a normal light cycle."
Professor Andrew Shennan, an expert in obstetrics for U.K. baby charity Tommy's, disagreed, saying the link between light exposure and its effects on mood and behavior were already widely recognized.
"Currently, any babies who are admitted to a special care baby unit are going to be exposed to incredibly harsh lighting to facilitate care, at anytime day or night that it is needed," he said. "Many units now try and reduce adverse stimuli including lighting for periods during the day and at night.
"As a result of this research the potential benefit of reducing unnecessary light exposure must now be investigated, as it would seem that there is a strong possibility that this could improve the development of the body clock."
The study -- published in the journal Pediatric Research -- used baby mice because they are born at a much earlier stage of development than human babies, which makes them an ideal parallel for studying premature babies, 14 million of which are born annually.
The harmful effects of artificial light has been documented before, as a study conducted by the U.S. National Cancer Institute and National Institute of Environmental Health Sciences suggested that exposure to light during sleep hours can promote breast cancer.
The scientists found that light shuts off the body's ability to produce melatonin, a sleep hormone that researcher say may provide immune system protection and fight off tumors.
For more information, read the full NaturalNews article.
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