According to research from University of Colorado Boulder, prebiotics can improve sleep and boost stress resilience by influencing gut bacteria and the metabolites they produce.
The research could lead to new forms of treatment, welcome news for the 70 million Americans who struggle with getting enough sleep.
The study's lead author, Robert Thompson, PhD, said the major takeaway is that prebiotics don't just exist for the bulking up of a stool and passing through the digestive system. The postdoctoral researcher added, "It is feeding the bugs that live in our gut and creating a symbiotic relationship with us that has powerful effects on our brain and behavior."
Prebiotics are dietary compounds that humans cannot digest, but serve as nourishment for the trillions of bacteria residing within our guts. While not all fibers are considered prebiotics, a lot of fiber-rich foods such as artichokes, leeks, onions, and certain whole grains are also rich in prebiotics.
Researchers started adolescent male rats on either standard chow or prebiotic-infused chow. The rats were given large amounts of specific prebiotics like the galactooligosaccharides (components present in cabbage and lentils), polydextrose (a food additive used as a sweetener), milk fat globular protein (common in dairy products), and lactoferrin (found in breast milk).
The animal’s physiological measures were tracked before and after the rats were stressed, including fecal samples used for gut metabolomics analysis.
The Animals consumed their respective diets for 7 weeks prior to the first fecal sample collection and then for 11 weeks. Animals were then exposed to inescapable tail shock stress or not, and four days following inescapable tail shock stress another fecal sample was taken.
Sleep was also measured, using in vivo biotelemetry.
The animals on the standard chow diet experienced an unhealthy flattening of the body's natural temperature and a decrease in healthy gut diversity after stress. The rats on prebiotics were able to buffer impacts.
The rats on the prebiotic diet spent more time in restorative non-rapid-eye-movement (NREM) sleep. After stress, they also spent more time in rapid-eye-movement (REM) sleep, which is believed to be critical for recovery from stress.
Senior author and Integrative Physiology Professor Monika Fleshner, director of the Stress Physiology Laboratory at the university, said, "We know that this combination of dietary fibers helps promote stress robustness and good sleep and protects the gut microbiome from disruption. With this new study, we wanted to try to identify the signal.”
The findings show that the rats on the prebiotic diet had a very different "metabolome.” The make-up of metabolites included higher amounts of fatty acids, sugars and steroids. The rats' metabolome also looked different after stress.
"Our results reveal novel signals that come from gut microbes that may modulate stress physiology and sleep," said Fleshner.
Fleshner added that this new research could lead to a new class of options for insomniacs who want natural remedies.
"Armed with this information, we might be able to develop a targeted therapeutic that boosts the molecules that buffer against stress and tamps down the ones that seem to disrupt sleep," she said. "It's exciting to think about."
Human studies are underway at CU Boulder.
Source: Scientific Reports
10, Article number: 3848 (2020). DOI: 10.1038/s41598-020-60679-y
“Dietary prebiotics alter novel microbial dependent fecal metabolites that improve sleep”
Authors: R. Thompson et al.