INTESTINAL health has a close connection with healthy brain function. New research from the University of Tsukuba in Japan suggests that gut bacteria may also influence normal sleep patterns by helping create important chemical messengers in the brain, such as serotonin and dopamine.
This finding could offer new hope for people who have difficulty sleeping or experience sleep-related health problems, such as insomnia, chronic fatigue, and mental fog.
“We found that microbe depletion eliminated serotonin in the gut, and we know that serotonin levels in the brain can affect sleep-wake cycles,” says the study’s lead author, Prof. Masashi Yanagisawa. “Thus, changing which microbes are in the gut by altering diet has the potential to help those who have trouble sleeping.”
This new research builds on a solid body of previous work, which established that elements of cognition and brain development have a strong link with intestinal microbial health and metabolism. The study appears in Scientific Reports.
Internal and external cues, such as circadian rhythms and eating, significantly affect sleep. Circadian rhythms are essential biological processes or functions that follow a 24-hour cycle based on the body’s internal clock.
One of the most important circadian rhythms is the sleep-wake cycle. Factors that alter or throw off the sleep-wake cycle can cause sleep disturbances.
Intestinal metabolism is closely connected to brain function by way of the circulatory system and vagus nerve, which create a network called the “brain-gut axis” or “microbiota-gut-brain axis.”
Research shows that the gut microbiome (the community of bacteria, viruses, and fungi that live in the gut) has an effect on elements of cognitive function, brain development, memory formation, circadian rhythmicity, and mental health.
When and what people eat affects the composition, size, and daily rhythms of the gut microbiota. Changes to the gut microbiota can alter intestinal metabolism because microbes belonging to the microbiota produce many gut metabolites — the molecules that result from the chemical reactions that occur during the process of digestion. Therefore, changing their diet may potentially improve a person’s sleep or reduce sleep problems. Should this prove to be the case, it would serve as a natural, fairly simplistic alternative treatment to sleep medications, which can have a range of negative side effects, including daytime drowsiness and gastrointestinal problems.
