A recent study has identified specific gut bacteria linked to food addiction and potential protective effects, offering new insights into the treatment of food addiction and related eating disorders.
New research reveals the mechanisms of communication between your brain and your gut.
An international team of researchers has identified certain gut bacteria linked to the development of food addiction in mice and humans, which may contribute to obesity. In addition, they have identified bacteria that have a protective effect against food addiction.
The research was recently presented at the Federation of European Neuroscience Societies (FENS) Forum 2024 and published simultaneously in the journal Intestine.
Professor Elena Martín-García, from the Neuropharmacology-NeuroPhar Laboratory of the Department of Medicine and Life Sciences at Pompeu Fabra University in Barcelona, Spain, told the FENS forum: “Several factors contribute to food addiction, which is characterised by a loss of control over food consumption and is associated with obesity, other eating disorders and alterations in the composition of gut bacteria – the gut microbiome. Until now, the mechanisms underlying this behavioural disorder were largely unknown.”
In his presentation at the FENS Forum, Professor Rafael Maldonado, who heads the laboratory, said: “These results from our study could allow us to identify new biomarkers of food addiction and, above all, to evaluate whether beneficial bacteria could be used as new potential treatments for this obesity-related behavior, for which there is currently a lack of effective therapeutic approaches. New potential treatments could involve the use of beneficial bacteria and food supplements.”
Methodology and bacterial influence
Professor Martín-García used the Yale Food Addiction Scale (YFAS 2.0) to diagnose food addiction in mice and humans. It contains 35 questions that humans must answer, and these can also be grouped into three criteria for use in mice: persistent food seeking, strong motivation to obtain food, and compulsive behavior.
She and her colleagues studied gut bacteria in mice that were both food-dependent and food-independent and found an increase in bacteria from a group called the phylum Proteobacteria and a decrease in bacteria from the phylum Actinobacteria in the food-dependent mice. These mice also had a decrease in another type of bacteria called wet from the Bacillota branch.
The researchers used the YFAS to classify 88 patients as food dependent or not. As in mice, there was a decrease in the phylum Actinobacteria and wet Increases in the Proteobacteria phylum were observed in food-addicted individuals. Further analysis showed that the results in humans correlated with those in mice.
Professor Martín-García said: “The results obtained in mice and humans suggest that the specific microbiota could have a protective effect in preventing food addiction. In particular, the strong similarities in the amount of wet have highlighted the potential beneficial effects of this particular gut bacteria. Therefore, we investigated the protective effects of oral administration of lactulose and rhamnose, which are nondigestible carbohydrates known as “prebiotics” that can increase the amount of wet in the intestine. We did this in mice and found that it led to an increase in the abundance of wet in mouse feces, alongside dramatic improvements in food addiction. We saw similar improvements when we gave the mice a
” data-gt-translate-attributes=”({“attribute”:”data-cmtooltip”, “format”:”html”})” tabindex=”0″ role=”link”>species of wet called Blautia wexlerae orally as a probiotic.
“Gut microbiota signatures in mice and humans suggest possible non-beneficial effects of bacteria belonging to the phylum Proteobacteria and potential protective effects of increased abundance of Actinobacteria and Bacillota against the development of food addiction.”
According to Professor Martín-García, these results show how intestinal bacteria influence brain function and vice versa. “We have demonstrated for the first time a direct interaction between intestinal composition and brain gene expression, revealing the complex and multifactorial origin of this important obesity-related behavioral disorder. Understanding the dialogue between behavioral alterations and intestinal bacteria is a step forward for future treatments of food addiction and related eating disorders.”
Neurobiological factors in food addiction
She also described work to determine how microRNAs (miRNAs) – small, single-stranded molecules that regulate gene expression and contribute to nearly every cellular process – are involved in food addiction. Changes in miRNA expression could be involved in the mechanisms underlying this disorder.
The researchers used a technique called Tough Decoy (TuD) to inhibit specific microRNAs in the medial prefrontal cortex (mPFC) of the mouse brain to create mice that were likely to develop food addiction. The mPFC is the part of the brain involved in self-control and decision-making. These are the mice that were also used in the study described above – the food-addicted mice.
They found that inhibition of miRNA-29c-3p promoted the persistence of the response and increased the vulnerability of mice to developing food addiction. Inhibition of another miRNA called miRNA-665-3p promoted compulsive behavior and vulnerability to food addiction.
Professor Maldonado said: “These two microRNAs could act as protective factors against food addiction. This helps us understand the neurobiology of loss of eating control, which plays a crucial role in obesity and related disorders. To better understand these mechanisms, we are currently studying how the gut microbiota and microRNA expression in the brain interact in mice.”
Professor Richard Roche, Deputy Head of the Department of Psychology at Maynooth University, Maynooth, County Kildare, Ireland, is Chair of the FENS Communications Committee and was not involved in the study. He said: “Compulsive eating and food addiction is a growing problem worldwide. Many factors contribute to it, particularly the environment in which people live and the availability of certain types of food. However, we have known for some time that there are likely contributing factors to eating disorders and the research by Professor Martín-García and colleagues shows how different types of gut bacteria impact brain function and vice versa in humans and mice. This understanding paves the way for the development of potential new treatments for eating disorders, and we look forward to seeing more research in this area.”
Reference: “Gut microbiota signatures of vulnerability to food addiction in mice and humans” by Solveiga Samulenaite, Alejandra García-Blanco, Jordi Mayneris-Perxachs, Laura Domingo-Rodríguez, Judit Cabana-Domínguez, Noèlia Fernàndez-Castillo, Edurne Gago-García, Laura Pineda-Cirera, Aurelijus Burokas, Jose Espinosa-Carrasco, Silvia Arboleya, Jessica Latorre, Catherine Stanton, Koji Hosomi, Jun Kunisawa, Bru Cormand, Jose Manuel Fernández-Real, Rafael Maldonado and Elena Martín-García, June 26, 2024, Intestine.
DOI: 10.1136/gutjnl-2023-331445