Led by an international research team, Professor Lin Lu of Peking University Sixth Hospital, the researchers discovered that gut bacteria actively influence sleep-wake cycles, and that microbial imbalance may contribute to the development of insomnia, sleep apnea, and other disorders.
According to the study, gut bacteria communicate with the brain through three main pathways: the vagus nerve, the immune system, and metabolic processes. These bacteria produce active compounds such as short-chain fatty acids (including butyric acid) that reduce inflammation and improve sleep quality. Other bacterial metabolites are also involved in the production of the mood-regulating hormones serotonin and melatonin, which regulate circadian rhythms.
The study highlighted that certain bacterial strains, such as Lactobacillus and Bifidobacterium, stimulate the production of gamma-aminobutyric acid (GABA), a key inhibitory neurotransmitter that helps the body relax and fall asleep.
Analyses showed a decrease in the diversity of gut microbes and a decline in the number of "beneficial" bacteria in patients with chronic insomnia and sleep apnea. Similar microbial changes were observed in people with disrupted circadian rhythms, such as night shift workers.
The researchers found that symptoms of this gut bacteria imbalance also appear in patients with neurodegenerative diseases accompanied by sleep disorders, such as Parkinson's disease, making gut bacteria a vital indicator for the early detection of these disorders.
