Newswise — Our bodies are inhabited by trillions of microorganisms, with specific microbes unique to each individual. Through experimentation, scientists have pinpointed certain factors that account for variation in the gut: diet, living conditions, exercise and maternal line. Now, scientists at University of California San Diego have discovered another factor that affects the composition of the gut microbiome: time of day.
In fact, the scientists have found that time of day is such an important factor that they’re calling on the National Institutes of Health (NIH) to require researchers to report it in their papers. In new work published in Nature Metabolism , the scientists report that daily fluctuations in the gut alter the microbiome so significantly that different bugs populate it in the morning and in the evening. That means that a researcher analyzing a stool sample collected at breakfast will reach radically different conclusions from a researcher analyzing a stool sample collected right before dinner.
The UC San Diego scientists propose that this variability is keeping gut microbiome researchers from being able to replicate each other’s experiments. “Unexplained variability and lack of replicability may be due to the fact that the microbiome oscillates throughout the day, with different populations of microbes dominating at different times,” said Amir Zarrinpar, M.D.
, Ph.D., gastroenterologist and associate professor of medicine at UC San Diego School of Me.