Or is it the other way around?
The twenty-four-hour cycle of physiological processes, known as the circadian rhythm, is present in virtually all living organisms. This even applies to the bacteria that live inside of our bodies. Although the circadian rhythms of internal microbes cannot be directly influenced by sunlight, they still tend to synch up with the circadian rhythm of the host creature. As researchers at Chicago’s Rush University Medical Center discovered in a recent study, this synchronization—or, in some cases, the lack thereof—can have a significant impact on human health.
Given the growing body of research that suggests a connection between the composition of internal microbial ecosystems and overall human heath, this should come as no surprise.
Researchers suspect that melatonin may play a key role in synchronizing the circadian rhythms of the body and its internal ecosystem. The hypothesized importance of melatonin seems reasonable enough considering the prevalence of melatonin in the digestive system: the gut contains four hundred times more melatonin than blood.
To test this hypothesis, researchers exposed certain bacteria (Enterobacter aerogenes, for example) to melatonin. The bacteria responded by swarming the melatonin furiously. The reasons for this remain unclear, but researchers believe it may be due to the fact that the ingestion of food stimulates the production of melatonin—thus leading microorganisms to associate the chemical with nutrition.
One conclusion was clear, however. “Melatonin dramatically synchronized the cultures” remarked Dr. Jiffin K. Paulose, a researcher in the aforementioned study by Rush University.
Ongoing research could reveal important insights—after all, many patients with gastrointestinal symptoms also experience the seemingly unrelated problem of insomnia and/or irregular circadian rhythms. With additional investment in research and experimentation, a link between these conditions could be uncovered, thus paving the way for new treatments.