The struggle is real: that powerful, almost magnetic pull toward a bag of chips or a candy bar, even when you know you shouldn’t. For years, scientists and doctors have pointed to the brain as the culprit—a complicated network of reward systems that can get hooked on processed foods just like they do on drugs. But a new study points to a surprising and completely different source for our eating habits: the trillions of bacteria living in our gut.
Researchers from an international team have found a direct link between specific types of gut bacteria and the development of food addiction in both mice and humans. Even more surprising, they discovered a “good” type of bacteria that seems to act like a shield, protecting against the behaviors that define this disorder. This research could be a huge step forward in treating food addiction, a condition that currently has no effective medical solutions.
The Link Between Brain and Bacteria
To figure out the biological connection, the research team, led by Professors Rafael Maldonado and Elena Martín-García, studied two groups of both mice and humans. To see if the mice were “addicted” to food, they trained them to press a lever for a sugary chocolate pellet. The researchers then watched to see which mice showed the most signs of food addiction, such as being obsessed with getting the pellets, working harder and harder for them, and being unable to stop. The mice that fit this description were categorized as “addicted,” even though they didn’t eat more or gain more weight than their non-addicted counterparts. This is an important detail; it shows that food addiction is more about the behavior than just overeating.
In the human part of the study, the researchers had 88 patients fill out a 35-question survey called the Yale Food Addiction Scale. This widely used tool helped them identify and classify patients who had a high risk for developing food addiction.
The results were a stunning match between species. When the scientists analyzed the gut bacteria of both the mice and humans, they found that those with food addiction had a completely different microbial profile than those without it. Addicted subjects had a higher number of bacteria from a group called Proteobacteria, which are often seen as less beneficial. At the same time, they had far fewer bacteria from a “good” group called Actinobacteria. It appears that a specific type of bacteria in this group, called Blautia, was particularly low in both the addicted mice and humans.
Can a Supplement Stop Cravings?
The scientists weren’t satisfied with just finding a connection; they wanted to see if they could prove it. In a crucial experiment, they gave the addicted mice a type of non-digestible carbohydrate known to boost the growth of the beneficial bacteria, Blautia. The result was remarkable: the mice’s addictive behaviors were significantly reduced. They saw the same positive change when they gave the mice direct oral doses of the Blautia bacteria itself. This experiment provides compelling evidence that the gut bacteria aren’t just an indicator of food addiction but are actively involved in causing it.
The researchers noted that the study only used “extreme subpopulations” of mice and humans, which means that the findings may not apply to everyone. The study also had a small sample size for the mice, with 13 addicted mice and 11 non-addicted mice, which may limit the broad application of the findings. These details are essential for any scientific inquiry.
The Future of Food
The implications of this research are significant. It reveals that the key to overcoming food addiction might not be as simple as strengthening willpower or treating psychological issues alone. Instead, a targeted treatment could involve restoring the balance of helpful bacteria in our gut through a dietary supplement or a specialized probiotic. In a world grappling with a global obesity crisis, these findings offer a new and hopeful path forward. They show us that the food we eat doesn’t just feed us—it also feeds a microscopic world within us that might be influencing our choices more than we ever thought.
Paper Summary
Methodology
This study used a dual-cohort design involving mice and humans to investigate the relationship between gut bacteria and food addiction. In mice, researchers used a 98-day operant training protocol with chocolate pellets to identify subjects with addiction-like behaviors. They then used the Yale Food Addiction Scale (YFAS 2.0) to classify 88 human patients. The gut microbiota of both addicted and non-addicted cohorts were analyzed to identify differences in bacterial signatures. Finally, they conducted a functional experiment on the mice to see if administering beneficial microbes or non-digestible carbohydrates would reverse the addiction-like behavior.
Results
The study found that both mice and humans with food addiction had a lower relative abundance of bacteria from the Actinobacteria phylum and a specific genus called Blautia. Conversely, they had a higher abundance of bacteria from the Proteobacteria phylum. The researchers demonstrated that giving addicted mice either non-digestible carbohydrates that promote Blautia growth or direct oral doses of the microbe led to a “dramatic improvement” in their addiction-like behaviors.
Limitations
The study notes that food addiction is a controversial concept. The mouse study had a small sample size (11 non-addicted and 13 addicted mice), and the researchers used “extreme subpopulations” of both mice and humans. The study also notes that it does not demonstrate the functional relevance of gut microbiota in the loss of eating control and food addiction.
Funding and Disclosures
The publication is protected by copyright and re-use is permitted under CC BY-NC. The authors list multiple affiliations, including the Universitat Pompeu Fabra in Barcelona, Spain. The paper was published by BMJ.
Publication Information
- Title: Gut microbiota signatures of vulnerability to food addiction in mice and humans
- Authors: Solveiga Samulėnaitė, Alejandra García-Blanco, Jordi Mayneris-Perxachs, et al.
- Journal: Gut
- DOI: 10.1136/gutjnl-2023-331445
