What is already known
Gut microbes have been shown to influence their host’s dietary choices and even regulate appetite. However, it’s unclear whether the gut microbiota can control binge-eating of palatable food such as sweets.
What this research adds
Researchers found that mice with microbiotas disrupted by antibiotics consumed 50% more sugar pellets than mice with intact gut bacteria. When their microbiotas were restored through fecal transplants, the mice returned to normal feeding behavior. In mice treated with antibiotics, the neuronal activity in brain regions involved in motivation and reward-seeking behavior was elevated after the animals ate the sugar pellets. High levels of Lactobacillii tended to suppress binge-eating behavior.
Conclusions
The findings suggest that the gut microbiota can influence binge-eating of sweet foods.
Gut microbes have been shown to influence their host’s dietary choices and even regulate appetite. Now, researchers have found that the gut microbiota can determine whether mice over-consume sugar pellets.
The findings, published in Current Biology, suggest that the gut microbiota can influence binge-eating of sweet foods.
A series of factors determine whether a person will eat or not, but feeding driven by pleasure — or hedonic feeding — is influenced by food palatability, “an ascribed valuation of food reward influenced by taste and past food-associated experiences,” the researchers say. “Palatable food exposure will promptly induce feeding in rodents, even when unfasted,” they add. This binge-eating behavior is typically observed when mice are given access to foods rich in sugar or fat.
Previous studies have associated gut bacteria with binge-eating, but it’s unclear to what extent the gut microbiota controls binge-eating of palatable food. To address this question, James Ousey at the California Institute of Technology and his colleagues disrupted the microbiota of mice with antibiotics and then gave them access to sugar pellets.
Sugar binge
Mice with microbiotas disrupted by antibiotics consumed 50% more sugar pellets than mice with intact gut bacteria, the researchers found. However, both groups of mice consumed the same amount of their regular diet, suggesting that disruption the gut microbiota only increases feeding of palatable foods.
Next, the researchers restored the mice’s microbiotas through fecal microbial transplants. Two weeks after transplant, mice treated with antibiotics had increased microbial diversity in their guts and their microbiota was more similar to that before the antibiotic treatment. These mice also returned to normal feeding behavior, the researchers found.
“Collectively, a complex gut microbiota is sufficient to suppress feeding induced by a high-sucrose diet in mice,” the authors say.
Feeding control
In a set of experiments where mice needed to push a button to receive a sugar pellet, animals treated with antibiotics put more effort into obtaining pellets than those with intact microbiotas. In mice treated with antibiotics, the activity of brain regions involved in motivation and reward-seeking behavior was elevated after the animals ate the pellets. However, the researchers say, “whether these effects are required for overconsumption of palatable foods remains unknown.”
The team also found that high levels of Lactobacilli tended to suppress binge-eating behavior. In particular, a mixture of Lactobacillus johnsonii and specific members of Bacteroidales was sufficient to reduce the overconsumption of sugar pellets in mice treated with antibiotics. Next, the researchers plan to investigate the mechanisms required for gut microbes to suppress binge-eating of palatable food.
Altered gut microbiotas have been linked to anorexia and binge-eating disorder in humans and mice, the authors note. “Future studies in our lab and others will explore the gut–brain axis in modulating reward circuits in the brain as well as possibly devising probiotics to intervene in eating disorders.”
