A study conducted by the Biomedical Research Institute of Girona Josep Trueta (IDIBGI) and Pompeu Fabra University (UPF) in Spain has found a connection between a type of virus in the gut microbiota, specifically Microviridae, and food addiction and obesity.
Previous research primarily focused on bacteria within the microbiota, but this discovery highlights the role of viruses in gut health and behaviors related to nutrition and metabolism. The findings were published in the journal Nature Metabolism.
The research also identified an amino acid in the bloodstream, anthranilic acid, which may protect against food addiction behaviors. Food addiction is characterized by a loss of control over eating, directly linked to obesity and mechanisms in the brain similar to those seen in other addictions.
The study correlates the presence of Microviridae with serotonin and dopamine metabolism, revealing that higher levels of tryptophan and tyrosine in the blood are associated with this virus. Tryptophan and tyrosine are precursors for serotonin and dopamine, neurotransmitters crucial for mood and pleasure regulation, which are involved in addiction mechanisms, including reward systems and satiety regulation.
Researchers emphasize the need to include viruses in gut microbiota studies, as the virome—an ecosystem of intestinal viruses—is unique and stable for each individual. This could lead to personalized strategies for treating food addiction, according to Jordi Mayneris-Perxachs, head of the IDIBGI's Systems Medicine and Integrative Biology group and a co-author of the study.
Co-author José Manuel Fernández-Real, who leads the Nutrition, Eumetabolism, and Health group at IDIBGI, stated that these findings enhance existing knowledge on the microbiota-brain relationship and clarify the role of components like Microviridae.
The conclusions were validated across three independent groups totaling 264 participants and align with results from another analysis involving 942 individuals, which found a link between Microviridae and reduced inhibitory control.
This association was also tested in mice and fruit flies. In collaboration with UPF researchers, transferring microbiota from patients with high Microviridae presence to mice resulted in increased food addiction and altered metabolism of tryptophan, serotonin, and dopamine, along with typical food addiction behaviors such as motivation, compulsivity, and persistence.
Rafael Maldonado, head of the UPF Neuropharmacology laboratory, noted that identifying this mechanism related to loss of control over food intake could lead to significant advancements in therapeutic strategies for effectively addressing eating disorders and associated complications like obesity.
Metabolomic analysis of patient blood confirmed that the presence of Microviridae was linked to lower concentrations of anthranilic acid, suggesting that this substance may prevent typical food addiction behaviors. To validate this hypothesis, anthranilic acid was administered to mice and fruit flies. In mice, UPF observed that supplementation with anthranilic acid reduced food addiction and altered pathways related to neurotransmitter metabolism and synthesis.
Experiments with fruit flies, led by IDIBGI researcher Anna Castells-Nobau, demonstrated that anthranilic acid regulated feeding behavior through dopamine metabolism.