Study Shows that Gut Bacteria Changes Your Mood and Behavior

What are Macros, and Should You Count Them?


  • In a recent study, scientists made the connection between specific strains in the gut bacteria of rats, and their mood and behavior.
  • Researchers found that high conflict rats had a different gut bacteria profile than rats who lived in a relaxed environment.
  • Researchers also found that transplanting the bacteria of stressed rats into the gut of relaxed rats made them take on stressed and depressive behaviors.
  • Keep reading to learn more about the connection between your microbiome and your mood.


In a recent study, scientists made the connection between specific strains in the gut bacteria of rats, and their mood and behavior.[ref url=””]

Rats were split into two groups — one group got to chill in a relaxed environment, and the others were grouped with aggressive rats to rile them up. Within the high conflict group, rats were categorized as resilient or vulnerable, depending on how quickly they backed down to the aggressive rats. After a few days of frequent conflicts, researchers analyzed the gut bacteria profile of fecal samples of both groups.

Researchers found that vulnerable rats had more Actinobacterium, Bacillus, and Clostridium strains and less Bacteroidetes than the rats who experienced zero conflict. The microbiome of resilient rats, who displayed confidence in the face of adversity, more closely resembled that of relaxed rats.

The research team took it a step further and tested whether or not transplanting the bacteria of high-conflict rats into relaxed rats changed their behavior. They found that relaxed rats who received transplants from vulnerable rats started to show behavioral signs of depression.

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Gut bacteria, mood, and behavior in humans

Although this was a rat study, it gives a larger picture of how gut bacteria influence your mood and behavior. It’s not the first study of its kind — the body of knowledge around the gut-brain connection is expanding every day. You can read about how your gut bacteria control your mind here, and here’s an article about the connection between gut bacteria, stress, and mood.

One of the best things you can do for your physical and mental health is to fix leaky gut, a condition where certain overgrowths lead to weak spots in intestinal walls, and to encourage a diversified gut microbiome. Here’s how to get started.





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