Gut Microbes Affect Metabolism and Circadian Rhythms in Mice, Study

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Previous studies on jetlag and working night shifts have linked metabolism with the circadian rhythms—the rhythms that control daily mental and physical functions.

However, in a new study published in the journal Cell Host & Microbe, researchers from the University of Chicago and the U.S. Department of Energy’s Argonne National Laboratory suggest that gut microbes can also play a vital role in metabolism and circadian rhythms—in mice.

The gut microbiome is a set of fungi, viruses and bacteria that is essential for digestion; it affects mental health, allergies, metabolism and an individual’s weight.

In the study, researchers discovered that mice with normal gut bacteria showed a regular microbial cycle on a daily basis. In this cycle, different bacterial species’ thrived at various parts of the day and produced different compounds. The compounds affected the activity of the circadian clock genes in the liver.

As a result, a high-fat diet reduced the variation of the microbial cycle in the mice; they gained weight after their circadian clock genes were disturbed. Mice without normal gut bacteria showed signs of a disturbed circadian clock cycle; however, they did not gain weight on the high-fat diet.

Study co-author and Argonne microbial ecologist, Jack Gilbert, commented on the study results, “The earlier explanation for microbiome-related weight gain was that some bacteria make calories from food more available to your body, but this is a fundamental alternative explanation.

“We’d like to more rigorously explore what kinds of diets trigger this response,” added Gilbert.

Sources for Today’s Article:
Leone, V., et al., “Effects of Diurnal Variation of Gut Microbes and High-Fat Feeding on Host Circadian Clock Function and Metabolism,” Cell Host & Microbe, 2015; 17(5): 681, doi: 10.1016/j.chom.2015.03.006.
“Gut microbes affect circadian rhythms and metabolism in mice,” ScienceDaily web site, Aug. 3, 2015;
“Circadian Rhythms Fact Sheet,” National Institute of General Medicals Sciences website;, last reviewed May 8, 2015.