We humans have internal clocks; we experience daily changes in our energy, mood, appetite and sleepiness based on time of day, light and dark, temperature and sleep patterns. These changes are known as circadian rhythms. Microbes in our gut, the so-called ‘microbiome’, have also been found to have circadian rhythms. Our gut bacteria make small rhythmical movements throughout the day and night. In so doing they impact our physiology and affect tissues far away from the gut, such as the liver. Gene expression in the liver can change in tandem with the microbiome’s rhythm changes, resulting in variations in important liver functions, such as drug metabolism and detoxification.
The new findings in a paper from the Weizmann Institute of Science in Israel, published 12/1/16 in the journal Cell, show that our circadian rhythms are deeply dependent on the oscillations of the gut microbes. Some of our daily rhythms are maintained but others are disrupted. Previous work by the authors of this study, Eran Elinay and Eran Segal, showed that disrupting feeding times and sleep-wake patterns in mice induced changes in the gut microbiome. Understanding more about this relationship could eventually help to find ways to intervene in obesity and it’s related metabolic problems, which are more common when circadian rhythms are disrupted due to shift work or jet lag. Also, since most drugs, from Tylenol to chemotherapy, are metabolized by the liver, a better understanding of gut/liver rhythms could affect how and when medications are taken or given. According to Eran Segal “What we learned from this study is that there’s a very tight interconnectivity between the microbiome and the host. We should think of it as one supraorganism that can’t be separated. We have to fully integrate our thinking with regard to any substance we consume.”
A take-home lesson from this study is that we should become more aware of our daily patterns of eating and sleeping, and try to keep them as regular as possible. Eating during the day and letting the gut rest at night is desirable. Also, remember that your gut microbiome thrives on the fiber found in vegetables and fruits. Think of yourself as a ‘supraorganism.’ !
Sadja Greenwood, MD, MPH back issues on this blog