Your gut might be more than just a “gut feeling” when it comes to stress; it’s actually running on its own daily schedule to help you cope. Gut bacteria—the ecosystem of tiny organisms inside of us—affect how well we handle stress, with their impact changing throughout the day, according to a new animal study. The research showed that gut bacteria influence the stress response, which is linked to the body’s natural sleep-wake cycle.
Disrupting gut bacteria in mice led to stress responses outside their normal circadian rhythm. Our body’s internal clock, known as the circadian rhythm, helps control many functions, including sleep patterns and hormone levels. When these natural rhythms fall out of sync, it can lead to health problems, including mental health issues and mood disorders.
Researchers found that when gut bacteria were depleted—either by giving antibiotics to regular mice to reduce gut bacteria or by using germ-free mice with no gut bacteria—stress responses became overactive at specific times of the day. This overactivity was linked to disruptions in the brain regions that control stress and circadian rhythms, leading to abnormal stress reactions, changes in hormone levels, and anxiety-like behavior in the mice. A fundamental discovery involved the bacteria Limosilactobacillus reuteri (L.
reuteri). This beneficial bacteria, commonly used in probiotics, fluctuates in abundance throughout the day. These fluctuations were linked to the release of stres.