Researchers have discovered specific gut bacteria that promote food addiction in both mice and humans, leading to obesity.

Their findings, presented at the Federation of European Neuroscience Societies (FENS) Forum 2024 and published in the journal Gut, also identified bacteria that may prevent food addiction.

Elena Martin-García, a professor at the Neuropharmacology-Neuroprotective Laboratory at the Universitat Pompeu Fabra in Barcelona, ​​Spain, explained that food addiction is marked by a loss of control over food intake and is associated with obesity, eating disorders, and alterations in gut microbiome composition.

“Until now, the mechanisms behind this behavioral disorder were largely unknown,” he added.

Professor Rafael Maldonado, head of the laboratory, highlighted the potential of these findings in identifying new biomarkers for food addiction and discovering beneficial bacteria as potential treatments.

He stated that current therapeutic approaches to this behavior are ineffective, and emphasized the need for new solutions involving beneficial bacteria and dietary supplements.

Using the Yale Food Addiction Scale (YFAS 2.0), the team diagnosed food addiction in both mice and humans. This 35-question scale for humans was adapted for mice based on criteria such as persistent food seeking, high motivation for food, and compulsive behavior.

Their investigations revealed that the food-addicted rats had increased amounts of Proteobacteria and decreased amounts of Actinobacteria and Blautia. Similar patterns were seen in food-addicted humans.

These findings suggest that certain microbiota may protect against food addiction, particularly Blautia, which has shown potential benefits in both mice and humans.

The researchers also tested the effects of prebiotics such as lactulose and rhamnose, which increase Blautia levels in the gut.

Giving these prebiotics to rats significantly improved symptoms of food addiction. In addition, giving the probiotic Blautia vexlera to rats also showed similar positive results.

“Characterization of the gut microbiota in both mice and humans suggests possible non-beneficial effects of Proteobacteria and protective effects of Actinobacteria and Bacillota against food addiction,” said Professor Martin-García.

He highlighted the complex interrelationship between gut bacteria and brain functioning and said that this research is the first demonstration of a direct interrelationship between gut composition and brain gene expression.

The team also explored the role of microRNAs (miRNAs) in food addiction.

Using Tough Decoy (TuD) technology to inhibit specific miRNAs in the middle prefrontal cortex of mice, they found that inhibiting miRNA-29c-3p and miRNA-665-3p increased susceptibility to food addiction by promoting persistent and compulsive behavior.

“These two miRNAs may act as protective factors against food addiction,” Professor Maldonado explained. Understanding their role could shed light on the neurobiology of loss of control over eating, which is important in obesity and related disorders. The researchers are now studying the interaction between the gut microbiota and miRNA expression in the brain in more depth.

This groundbreaking research by Professor Martin-García and his colleagues paves the way for future treatments targeting the gut-brain axis to tackle food addiction and obesity.