New research shows that neuronal circuits interlink your brain and gut to communicate.
An international team of researchers has identified specific gut bacteria that are associated with the development of food addiction in mice and humans, a major contributing factor to obesity, but they also found bacteria which were protective against food addiction.
Their work has just been presented at the Forum 2024 of the Federation of European Neuroscience Societies (FENS) and is published simultaneously in the journal Gut.
Told the FENS Forum Professor Elena Martín-García, Laboratory of Neuropharmacology-NeuroPhar, Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona, Spain: “A number of factors contribute to food addiction, a disorder characterized by loss of control over food intake and associated with obesity, other eating disorders, and alterations in composition of bacteria in gut – the gut microbiome”. Up until now, mechanisms of this behavioral disorder were mostly unknown.
Speaking before the FENS Forum, Professor Rafael Maldonado, who leads the Laboratory, said: “These results from our study may allow us to identify new biomarkers for food addiction and, most importantly, to evaluate whether the beneficial bacteria could be used as potential new treatments for this obesity-related behavior, which, at present, lacks any effective therapeutic approaches. This could include new potential treatments using beneficial bacteria and dietary supplementation.
Methodology and Gracterial Influence
Prof. Martín-García used the Yale Food Addiction Scale, YFAS 2.0, which diagnoses food addiction in mice and humans. It contains 35 questions for human answers, and these can also be grouped into three criteria for application in mice: persistent pursuit of food, high motivation to gain access to food, and compulsive behavior.
She, with her colleagues, ran an experiment on gut bacteria of mice that are addicted and are not addicted to food. In the food-addicted mouse, she found an increase in bacteria belonging to a group called the Proteobacteria phylum and a decrease in bacteria belonging to the Actinobacteria phylum. These mice also showed a decrease in another type of bacteria amount called Blautia of the Bacillota phylum.
The researchers used the YFAS to divide 88 patients into those who were addicted or not addicted to food, before comparing their microbiomes. They found reduced Actinobacteria phylum and Blautia, with increased Proteobacteria phylum, in the food-addicted individuals, as in the mice. Further analysis showed how the human findings related to those in mice.
Indeed, according to Prof. Martín-García, “The findings in both mice and humans suggested that specific microbiota could be protective in preventing food addiction. Specifically, strong similarities in the amount of Blautia underlined possible positive effects of this particular gut bacteria. It has already been shown that human and murine models of obesity or overeating are characterized by low Faecalibacterium counts. In the present study, we explored if this was a consequence of oral administration of lactulose and rhamnose, non-digestible carbohydrates known as ‘prebiotics’ which increase the amount of Blautia in the gut. We did this in mice, and results showed increased abundance of Blautia in mice faeces paralleled with dramatic improvements in food addiction. We saw parallel improvements when we provided the mice with an oral probiotic called Blautia wexlerae, a species of Blautia.
“The gut microbiota signatures in both mice and humans suggest possible non-beneficial effects of bacteria belonging to the Proteobacteria phylum and potential protective effects of elevating the abundance of Actinobacterial and Bacillota against the development of food addiction.”.
According to Prof. Martín-García, they show that gut flora influences brain function and vice versa. “For the first time, we have shown direct interaction between gut composition and brain gene expression, showing the complex and multifactorial origin of this important behavioral disorder related to obesity. The understanding of the crosstalk between alterations in behavior and bacteria in the gut may constitute a step forward for the future treatments of food addiction and related eating disorders.”.
Neurobiological Factors in Food Addiction
She further commented on a study investigating how microRNAs—small, single-stranded molecules that regulate gene expression and endogenously modulate almost any cellular process—are implicated in food addiction. Differential expression of miRNAs could underlie the mechanisms of the disorder.
To create mice that are prone to the development of food addiction, the researchers used a TuD technique to repress specific miRNAs in the mPFC region of the brain. In human beings, this area of the brain is responsible for self-control and decision-making. As it happens, these same mice were employed in the above study—namely, food-addicted mice.
They found out that miRNA-29c-3p inhibition favored resistance to extinction and increased the propensity in mice to acquire food addiction. Another miRNA, miRNA-665-3p, when its level was reduced, favored compulsive behavior and vulnerability to food addiction.
According to Prof. Maldonado, “These two miRNAs play a protective role against food addiction. This can be clarifying that the neurobiological mechanisms of loss of control in eating are key factors for obesity and related disorders. Therefore, to explore these mechanisms, in the present study we investigate the interplay between the gut microbiota and miRNA expression in the brain in mice.”.
Professor Richard Roche, Deputy Head of the Department of Psychology at Maynooth University, Maynooth, County Kildare, Ireland, is chair of the FENS communication committee and was not involved in the research. He said: “Compulsive eating and food addiction is a growing problem worldwide. There are many factors that contribute to it, in particular the environment that people live in and the availability of certain types of food.”. However, we’ve known for some time that there are probably contributing factors for eating disorders, and research by Professor Martín-García and colleagues indicates how the different types of bacteria in the gut have a bearing on brain function and vice versa in humans and mice. Such understanding opens up the avenue for the development of possible new treatments for eating disorders and warrants further research.
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, 26 June 2024, Gut.
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Source: SciTechDaily