Study finds specific gut microbiota signature is associated with vulnerability to food addiction

By Pooja Toshniwal PahariaReviewed by Danielle Ellis, B.Sc.Jul 1 2024

Researchers of a recent study published in Gut explored gut microbial involvement in food addiction-related processes.

Background

Uncontrolled food consumption can lead to obesity and gut microbial alterations. Brain changes associated with behavioral disorders impact the gut microbiome, and gut microorganisms influence brain areas involved in behavioral regulation.

Recent research on gut microbiome profiles linked to addictive eating has sparked interest; however, studies predominantly included rodents, underscoring the scarcity of translational research to confirm human findings using animal models.

About the study

In the present study, researchers examined the functional role of gut bacteria in food addiction and uncontrolled eating.

C57Bl/6J mice were subjected to operant food addiction procedures for six reinforcement sessions using the fixed ratio (FR) 1 and 92 regular FR5 sessions. The researchers used the Yale Food Addiction Scale (YFAS) to assess food addiction among mice and humans.

They functionally confirmed the importance of Blautia microbes, which are most differently expressed among addicted murine and human populations, by providing non-digestible-type carbohydrates such as rhamnose and lactulose and examining their fecal microbiome.

They also used quantitative polymerase chain reaction (qPCR) gene expression in the mouse food addiction technique to validate its functionality with Blautia therapy. Genes evaluated included dopamine receptor type 1 (DRD-1), DRD-2, tyrosine hydroxylase, and dopamine and cyclic adenosine monophosphate-regulated neuronal phosphoprotein (DARPP-32).

The researchers orally administered Blautia wexlerae to mice enduring lengthy food addiction protocols three days per week at a dosage of 1.0 × 109 colony-forming units. They used 16S ribosomal ribonucleic acid (rRNA) sequencing of cecum contents to detect gut microbial profiles linked to uncontrolled eating-like behavior.

The researchers used principal component analysis (PCA) on primary variables such as response persistence, compulsivity, motivation, withdrawal, tolerance, distress, and appetite. Correlational assessments displayed addiction criteria in mice and humans together.

In addition, the researchers used a correlation matrix to investigate the relationship between each addiction criterion and each phenotypic characteristic in murine and human populations. Study covariates included age, body mass index (BMI), and biological sex.

Results

The research identified gut microbiome patterns of food addiction as prospective biomarkers. The gut microbiome profiles related to food addiction were strikingly comparable between the mouse and human groups.

The findings indicated that proteobacteria may negatively impact food addiction development in mice and humans, whereas actinobacteria may have a protective effect.

The researchers discovered a lower Blautia wexlerae relative abundance among addicted individuals and the Blautia genus among addicted mice. Rhamnose and lactulose that promote Blautia development increased Blautia abundance in murine feces while significantly improving food addiction. The team noted comparable improvements following Blautia wexlerae administration, a beneficial microorganism.

Firmicutes and Bacteroidetes dominated the mouse caecal microbiota, accounting for about 90% of the relative abundance in addicted and non-addictive animals. Certain bacteria, such as the Actinobacteria phylum, Erysipelotrichaceae, Coriobacteriaceae families, Enterohabdus, and Lachnospiraceae genera, were shown to be less abundant in addicted mice than in non-addicted mice.

Genus-level analysis showed that the Ruminococcaceae and Gastranaerophilales genera were positively associated with motivation among addicted mice. Lachnospiraceae, Ruminococcaceae, Candidatus arthromitus, Peptococcus, Ruminiclostridium_6, Acetatifactor, Coprococcus_1, and Roseburia showed positive correlations with response persistence among addicted mice.

Diet composition had a minimal impact on gut microbiota data. In mice, the desire for chocolate-flavored pellets was much lower in the rhamnose group than in the lactulose group, demonstrating that non-digestible carbohydrates can help avoid food addiction. Blautia-treated animals had identical response persistence but much lower desire and compulsivity for attractive foods than control mice.

Animals that met food addiction requirements had reduced abundances of numerous essential bacterial groups, indicating possible protective benefits. In contrast, addicted mice had an increase in the relative abundance of the Anaeroplasmagenus and the Gastranaerophilales families, indicating that the effects were unfavorable.

The findings showed that an increased relative abundance of the Enterorhabdus genus (Actinobacteria) in the guts of non-addicted mice may be advantageous, and the Lachnospiraceae genus from the Bacillota or Firmicutes phylum may have a favorable effect on food addiction, consistent with previous research. The qPCR analysis showed non-significant differences in gene expression between Blautia-treated mice in the primary areas of the reward system, including the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC).

Conclusion

The study findings indicated a link between gut microbiota and food addiction risk. The gut microbiome composition was associated with primary addiction characteristics, including motivation and response persistence. Blautia, a non-digestible carbohydrate, was functionally relevant and effective in preventing food addiction development in rats.

The findings indicate that gut microbiota may predispose individuals to food addiction, which might lead to new techniques for creating biomarkers and novel treatments for uncontrolled eating and related disorders.