Important Points:
- Diabetes
- Chronic Fatigue Syndrome
- Fatigue
- Multiple Sclerosis
How do gut bacteria affect brain health?
Gut bacteria shape how the brain works. In mice, a germ-free gut lowered anxiety and increased myelination. Myelin is the protective coating that breaks down in multiple sclerosis. Human studies tie gut bacteria to type 2 diabetes and chronic fatigue syndrome.
Our brain is one of the most complex living structures known to man. Until recently, we saw the brain as the sole center of how our body works. But new information tells us the brain might not be working on its own. We would never normally link the brain’s complex work with the system that processes our food. Yet there is a strong connection. How our brain works is heavily shaped by our gut, and by our gut bacteria in particular.
Science has shown that there are good and bad microbiota (bacteria) in our digestive system. Their careful balance matters for our nutrition and, in the end, our survival. According to the study done by the European Academy of Neurology, the job of those bacteria may not be limited to nutrition alone. The researchers found that this microbiota can bring out bravery. It can even trigger the disease process for multiple sclerosis. The research shows that mice with a germ-free gut are relaxed and fairly free from anxiety. That makes them braver. It also showed that a germ-free gut is associated with more myelination, the brain’s protective coating. A lack of myelin, or damage to the myelin sheath, is one of the disease processes behind Multiple Sclerosis.
The strong link between the gut and the brain does not end there. A research finding published by the University of Illinois shows that gut microbiota can change the body’s endocrine (hormone) function. The study found that black males with Type 2 Diabetes have a significantly lower number of good bacteria and more of the bad ones.
Another recent study confirms that a healthy microbiota matters for healthy rest. It was published by Cornell University. In Chronic Fatigue Syndrome, normal activity causes extreme weakness that rest does not relieve. It has stumped doctors for decades. The findings showed that people with the condition have a distinct inflammation in the gut. Further analysis found that people with chronic fatigue syndrome have gut bacteria that can trigger the immune response behind this disabling condition.
Recent studies all point to the significance of the gut in neurologic (brain and nerve), endocrine, and inflammatory diseases. Perhaps a better approach is to look in the gut for the culprits first, instead of focusing on the affected organ. It also opens the door to new classes of drugs that can change the microbiota instead of targeting the brain itself.
Frequently asked questions
What is the gut-brain connection?
The gut-brain connection is the link between your digestive system and how your brain works. Your gut holds both good and bad bacteria. Their balance matters for more than nutrition. Research ties these bacteria to anxiety, multiple sclerosis, type 2 diabetes and chronic fatigue syndrome. That is why the gut is worth checking first, instead of looking only at the organ that is affected.
Can gut bacteria affect anxiety?
Yes, in animal research. The European Academy of Neurology reported that mice kept with a germ-free gut were more relaxed, largely free of anxiety and noticeably braver. The finding shows that the bacteria in your gut can change behavior, not only digestion. It is one reason researchers now look to the gut when they study the brain.
Are gut bacteria linked to multiple sclerosis?
Research points that way. The same European Academy of Neurology work found that gut bacteria can trigger the disease process behind multiple sclerosis. When mice were kept germ-free, their brains built more myelin, the protective coating around nerve fibers. Loss of myelin, or damage to it, is one of the core problems in multiple sclerosis.
Is chronic fatigue syndrome connected to the gut?
A Cornell University study says yes. Chronic fatigue syndrome causes extreme weakness after normal activity that rest does not fix. It stumped doctors for decades. The researchers found that people with the condition carry a distinct inflammation in the gut. They also found that their gut bacteria can set off the immune response behind the illness.
Do gut bacteria play a role in type 2 diabetes?
They appear to. A University of Illinois at Chicago study found that gut bacteria can change the body’s hormone (endocrine) function. Black men with type 2 diabetes in that study had significantly fewer good bacteria and more bad ones. Along with the brain findings, it shows how much of the body’s chemistry runs through the gut.
Related reading
Sources
European Academy of Neurology. (2016, May 29). Connections between gut microbiota and the brain. ScienceDaily. Retrieved July 5, 2016 from www.sciencedaily.com/releases/2016/05/160529174445.htm
University of Illinois at Chicago. (2015, March 6). Gut bacteria may contribute to diabetes in black males. ScienceDaily. Retrieved July 5, 2016 from www.sciencedaily.com/releases/2015/03/150306102752.htm
Cornell University. (2016, June 27). Chronic fatigue syndrome is in your gut, not your head. ScienceDaily. Retrieved July 5, 2016 from www.sciencedaily.com/releases/2016/06/160627160939.htm
Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP
Interventional pain physician, addiction medicine specialist and obesity medicine diplomate.
Licensed in Missouri and Illinois.
Last reviewed June 18, 2026
