Bad sleep turned out to be an unexpected threat to the gut

A large-scale study has revealed a bidirectional link between sleep characteristics and gut microbiome composition: people with better sleep quality and less pronounced social jet lag have greater gut bacterial diversity and a higher proportion of beneficial species. The study was published in the journal Nature Communications (NatCom).

Scientists analyzed data on sleep patterns, chronotype, and so-called social jet lag — the discrepancy between a person's internal biological clock and their actual schedule on weekdays and weekends — in several thousand volunteers. It turned out that it is the disruption of biorhythms, rather than simply lack of sleep, that is associated with reduced microbial diversity and an increase in pro-inflammatory bacteria in the gut.

The mechanism proved to be bidirectional. Gut bacteria are directly involved in the production of serotonin, melatonin, and GABA — key neurotransmitters that regulate the sleep-wake cycle. But the reverse influence is no less significant: sleep disruption alters peristalsis, acidity, and the immune response of the intestinal mucosa, paving the way for pathogenic species and suppressing beneficial flora.

The authors pay particular attention to social jet lag: shifting wake-up time by just one to two hours on weekends already shows a noticeable correlation with changes in microbial composition. At heightened risk are night-shift workers, students, and frequent travelers: not only their microbiome suffers, but also the metabolic processes associated with it. The scientists' conclusion is simple and emphatic: go to bed and wake up at the same time all seven days of the week and sleep no fewer than six to eight hours per day.