What happens in your gut and mouth might matter just as much as what goes on in your brain when it comes to getting a good night’s rest. Scientists are finding that the communities of microbes we carry, trillions of bacteria, viruses, and fungi collectively known as the microbiome, may play a surprising role in regulating sleep.
Most studies on microbes and sleep have focused on the gut, but a team from the Alpert Medical School of Brown University turned their attention to the mouth. Their study, published in SLEEP, examined whether oral microbiome diversity was linked to how much rest young adults get.
The latest research links microbial diversity to how long we snooze and adds to the body of knowledge on how well we cycle through sleep stages, and even how our body clock ticks in relation to our microbiome composition. The hope is that one day these discoveries could inspire new treatments, from probiotics designed to calm restless nights to microbiome-based therapies for more serious conditions like sleep apnea.
Oral Microbiome Diversity Increases with More Sleep
The team from Brown University analyzed data from the U.S. National Health and Nutrition Examination Survey (NHANES) between 2011 and 2012, focusing on 1,332 participants aged 16 to 26. Oral rinse samples provided a snapshot of the microbial mix in each participant’s mouth, while self-reported sleep hours revealed their routines.
The results showed that young adults who consistently got the most sleep, about three percent of participants, had significantly more diverse oral microbiomes than their peers. Because greater microbial variety is generally tied to better health, this adds weight to the idea that the body’s microbial communities help shape sleep.
Read More: The Gut Microbiome: 100 Trillion Microorganisms in Our Digestive Tract Maintain Our Healths
Linking the Microbiome with Sleep Quality
The mouth isn’t the only place where microbes matter. Looking at the gut, research revealed that people with chronic insomnia tend to have lower microbial diversity than those without the sleep disorder. Those with “social jetlag” (a mismatch between weekday and weekend schedules) also show distinct microbial patterns.
Another interesting insight shows that short sleepers often crave more sugar, shifting the gut environment. At the same time, microbes may influence sleep directly. Certain bacterial groups, such as Firmicutes, are suspected of affecting circadian rhythms — the internal clock that guides sleep and wake cycles.
Experiments back this up. Volunteers given certain antibiotics that disrupted their microbiomes showed reduced non-REM sleep, the restorative phase when the body repairs itself and consolidates memories. Likewise, disrupted sleep can weaken the immune system, giving less helpful microbes room to thrive, which may in turn worsen sleep, and overall health.
Fecal Transplants and Probiotics Could Restore Sleep
If microbes help set the rhythm of our sleep, could adjusting them be a new kind of treatment? There are reasons to think so. Many gut bacteria produce neurotransmitters like serotonin, dopamine, and GABA, as well as beneficial short-chain fatty acids, all involved in sleep regulation.
Some of the most striking results come from fecal transplant studies. Here, researchers transplanted gut microbes from people with insomnia and jetlag into mice. The animals developed similar disturbances, staying awake during rest hours, gaining weight, and blood sugar issues. Small human trials in China suggest that fecal transplants could also improve sleep in patients with long-standing insomnia, though this approach isn’t ready for mainstream use.
Probiotics (beneficial bacteria) and prebiotics (fibers that feed them) are already being tested for sleep problems. While larger trials are needed, early findings suggest they may complement existing therapies, especially for the people with chronic insomnia who don’t respond to first-line treatment.
This article is not offering medical advice and should be used for informational purposes only.
Read More: It Doesn't Take Long to Reset Your Gut Health with Small Lifestyle Changes
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
- Advances in Nutrition: Short Sleep Duration and Dietary Intake: Epidemiologic Evidence, Mechanisms, and Health Implications
- European Journal of Nutrition: Exploring the relationship between social jetlag with gut microbial composition, diet and cardiometabolic health, in the ZOEPREDICT1 cohort
- Nature: Molecular Psychiatry: Gut microbiota regulate insomnia-like behaviors via gut-brain metabolic axis
- Sleep: 0360 Associations of Sleep and Oral Microbiome Among Adolescents and Young Adults in the United States
