Scientists studied how different diets affect the health and behavior of small rodents called degus. They found that diet dramatically changes which bacteria live in the gut, and these bacteria may influence how well the brain works. One diet improved memory but made animals more anxious, while another diet reduced anxiety but had different effects on thinking. This research shows that what we eat doesn’t just fill our stomachs—it changes the tiny organisms living inside us, which then affects our mood, anxiety, and thinking abilities. The findings suggest that diet choices matter far more than scientists previously realized when studying animal behavior and health.

The Quick Take

  • What they studied: How two different types of food affect the gut bacteria, brain function, and behavior of small rodents called degus
  • Who participated: Captive degus (small rodents similar to guinea pigs) fed one of two standard laboratory diets over a study period
  • Key finding: The diet with added vitamin C improved memory and social interest but increased anxiety, while the plant-based diet reduced anxiety and created more diverse gut bacteria. The connection between gut bacteria and brain function appears to be the key link between diet and behavior.
  • What it means for you: Your diet shapes which bacteria live in your gut, and these bacteria may influence your mood, anxiety levels, and thinking ability. Choosing foods with diverse plants may support better mental health, though more research in humans is needed to confirm this.

The Research Details

Researchers divided degus into two groups and fed each group a different standard laboratory diet for the study period. One diet (LabDiet) contained added vitamin C and was more processed, while the other (Champion) was plant-based with more fiber variety. The scientists measured how well each diet was digested, tested the animals’ behavior and memory, and analyzed the bacteria living in their guts using genetic testing.

They also used a special statistical method called structural equation modeling to map out how diet, gut bacteria, and brain function were all connected to each other. This allowed them to see which factors influenced which other factors, rather than just looking at them separately.

This approach is valuable because it shows not just that diet matters, but how and why it matters—by revealing the chain of events from food choice to brain changes.

Understanding how diet shapes gut bacteria and brain function is important because it explains why the same experiment can give different results in different labs. If one lab uses one diet and another lab uses a different diet, the animals’ behavior might be different not because of the experiment itself, but because of what they ate. This research shows scientists need to pay attention to diet when designing studies.

This study was published in Scientific Reports, a well-respected scientific journal. The researchers used multiple measurement methods (behavior tests, genetic analysis of bacteria, and chemical analysis of gut contents) to verify their findings. The statistical analysis was sophisticated, using structural equation modeling to understand relationships between variables. However, the exact number of animals studied was not specified in the abstract, which limits our ability to assess statistical power. The findings are from one type of rodent and may not directly apply to humans without further research.

What the Results Show

Animals fed the vitamin C-supplemented diet (LabDiet) showed three main changes: they absorbed nutrients more efficiently, they had higher levels of acetic acid in their feces (a chemical produced by beneficial bacteria), and they had more Bifidobacterium bacteria in their guts. These animals performed better on memory tests and showed more interest in social interaction with other animals.

However, these same animals displayed more anxiety-like behaviors, such as freezing or avoiding open spaces. This suggests that while the diet improved some aspects of brain function, it may have increased stress responses.

Animals fed the plant-based diet (Champion) showed a different pattern. They had lower anxiety levels and much greater diversity of bacteria in their guts, with higher amounts of two bacterial groups called Bacteroidota and Tenericutes. The structural equation analysis revealed that diet was the primary driver of changes in gut bacteria, and that acetic acid levels (produced by the bacteria) were positively linked to better memory performance.

Natural behaviors like burrowing and nest-building were not affected by either diet, suggesting that diet influences higher-order brain functions (like memory and anxiety) more than basic instincts. The vitamin C supplementation in LabDiet appeared to be a key factor driving the differences in bacterial composition, as vitamin C is known to influence which bacteria can survive in the gut.

This research builds on extensive previous studies in mice and rats showing that gut bacteria influence brain function through the ‘gut-brain axis.’ However, this is one of the first detailed studies of this relationship in degus, which are increasingly used in aging and neurodegeneration research. The findings align with previous research showing that short-chain fatty acids (like acetic acid) produced by gut bacteria support cognitive function, but extend this knowledge by showing how different diets create different bacterial communities that produce different amounts of these beneficial chemicals.

The study was conducted in captive rodents, so results may not directly apply to humans or wild animals. The specific number of animals in each group was not provided, making it difficult to assess whether the sample size was large enough to detect real differences. The study measured behavior in a laboratory setting, which may not reflect how animals behave in natural environments. The research is observational rather than experimental, meaning we can see associations between diet and outcomes but cannot definitively prove that diet caused the changes. Finally, the study was relatively short-term, so we don’t know if these effects persist over longer periods.

The Bottom Line

Based on this research, eating a diet with diverse plant-based foods appears to support better anxiety management and gut bacterial diversity (moderate confidence). Consuming foods that support beneficial bacteria like Bifidobacterium may support memory and cognitive function (moderate confidence). However, these findings are from animal studies and should not be considered medical advice. Consult with a healthcare provider before making major dietary changes, especially if you have anxiety, cognitive concerns, or digestive issues.

This research is most relevant to scientists designing animal studies, who should standardize diet to ensure reproducible results. It’s also interesting for people concerned about anxiety, memory, or gut health, though human studies are needed to confirm these findings apply to people. People with diagnosed anxiety disorders or cognitive concerns should work with healthcare providers rather than relying on diet alone.

Changes in gut bacteria composition can occur within days to weeks of dietary changes, but stabilization typically takes 2-4 weeks. Behavioral changes like reduced anxiety may take 4-8 weeks to become apparent. Memory improvements might take similar timeframes. Individual variation is significant, so some people may see changes faster or slower than others.

Want to Apply This Research?

  • Track daily food intake by plant diversity (number of different plant-based foods consumed) and monitor weekly anxiety levels using a simple 1-10 scale and mood notes. Also track digestive comfort and energy levels to correlate with dietary changes.
  • Gradually increase the variety of plant-based foods in your diet by adding one new vegetable, fruit, legume, or whole grain each week. Aim for at least 5-7 different plant foods daily. Log which foods you add and note any changes in mood, anxiety, or digestive comfort.
  • Create a 12-week tracking plan: Week 1-2 establish baseline anxiety and mood levels; Weeks 3-8 gradually increase plant food diversity while tracking changes; Weeks 9-12 assess whether anxiety decreased, mood improved, or digestive comfort increased. Use the app to identify patterns between specific foods and mood/anxiety changes.

This research was conducted in rodents and has not been directly tested in humans. The findings suggest associations between diet, gut bacteria, and brain function but do not prove causation. This information is for educational purposes only and should not replace professional medical advice. If you experience anxiety, memory problems, or digestive issues, consult with a qualified healthcare provider before making dietary changes. Do not use this information to self-diagnose or self-treat any medical condition. Individual responses to dietary changes vary significantly based on genetics, existing health conditions, medications, and other factors.