Eliminating certain gut bacteria causes mice to binge-eat foods high in sugar. The corresponding study was published in Current Biology.
“The gut microbiome has been shown to influence many behaviors and disease states in mouse models, from sociability and stress to Parkinson’s disease,” said Sarkis Mazmanian, Professor of Microbiology at Caltech, one of the study’s authors, in a press release.
“The recent appreciation that feeding behaviors, driven by motivation, are subject to the composition of the gut microbiome has implications not just to obesity, diabetes, and other metabolic conditions but perhaps to overuse of alcohol, nicotine, or illicit substances that bring pleasure,” he continued.
In the current study, the researchers wanted to see how gut microbiota affects feeding behaviors. To do so, they gave a group of mice antibiotics for four weeks to eliminate their gut bacteria, and then compared their feeding behavior to that of mice with healthy microbiota.
While both mice ate similar amounts of the standard mouse diet, they noted that the antibiotic-treated mice ate considerably more high-sucrose pellets. Over a two-hour period, they ate 50% more of these pellets - and in longer bursts- than their healthy counterparts.
When presented with a button to press in order to receive sugar pellets, the antibiotic-treated mice spent considerably longer pressing it than healthy mice. This showed that antibiotic-treated mice were more willing to exert more effort than healthy mice to consume sugar.
The researchers noted, however, that the binge-eating behavior was reversible. After receiving a fecal transplant, the antibiotic-treated mice no longer exhibited the same overeating behavior.
To understand which microbes were involved in the process, the researchers observed the effects of different kinds of antibiotics on mice. They found that mice given ampicillin or vancomycin- but not neomycin or metronidazole- displayed binge-eating behavior. This suggested that bacteria linked to these antibiotics disrupted feeding behavior.
From further tests, the researchers found that bacteria specific to lab mice from the Lactobacillus group were linked to reduced binge-eating. Antibiotic-treated mice given this bacteria- but not others- exhibited suppressed overeating behavior.
The researchers are interested to see if people exhibit different eating patterns and dietary choices after consuming antibiotics. They noted that future studies will explore the underlying neurobiology of their findings, as well as possibly devise probiotics to treat eating disorders.
Sources: Neuroscience News, Current Biology