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The Human Gut Microbiome Fluctuates Throughout the Day and Seasons, Study Shows

Public Health, Public Health & Prevention

A new study presented at the Digestive Disease Week 2023 conference reveals that the human gut microbiome changes throughout the day and across seasons. The research indicates that factors such as light, temperature, humidity, pollen, diet, and fasting periods, like sleep, affect gut microbiome changes. It analyzed data from about 20,000 stool samples from populations worldwide collected between 2013 and 2019 as part of the American Gut Project. Researchers found that some related groups of bacteria exhibited a 24-hour cycle, while others had distinct patterns throughout the year. One bacteria, actinobacteria, fluctuated throughout the day, with lower levels in the morning and higher levels at the end of the day. Proteobacteria declined to deficient levels in winter and rose throughout the year before surging in summer. The study's lead author, Carolina Dantas Machado, Ph.D., emphasized that seasonal variations in allergies and other conditions occur in the context of different microbiomes, which may require a new understanding of how seasons impact health and disease. While more research is necessary to draw conclusive results, the findings suggest that fluctuations in the microbiome could have wide-ranging impacts on health and medicine.