Gut Bacteria: Do They Control Our Brains?

While scientists have studied the interaction between our gut and our brain for many years, some researchers are beginning to think the connection is quite complex. It may be that our brains are significantly influenced by the bacteria in our gut.

Your gut has natural defenses against harmful pathogens. In addition, your gut encourages the growth and survival of healthy bacteria. The majority of these bacteria reside in the colon, which harbors around 1 trillion bacteria in each gram of intestinal content. It is difficult to accurately count the number of bacteria in your gut. However, a good estimate is that your gut is home to around 40 trillion of them. In contrast, your entire body is made up of around 30 trillion cells, not including the bacteria in your gut.

Most of the gut bacteria fall into one of 30 to 40 species. However, there can be up to 1,000 different species. Together, we call this the gut microbiome. Many of those bacteria give us positive benefits. Some species break down dietary fiber into short-chain fatty acids making them easier to absorb. They metabolize many compounds and play a role in the synthesis of vitamins B and K.

Other research shows that dysregulation of the gut microbiome can be a significant factor in inflammatory diseases and autoimmune disorders. As scientists delve more deeply into these interactions, they are finding that our gut bacteria can moderate our brain and behavior.

Why is the gut linked to the brain?

What happens in your gut can literally be a matter of life or death. If the gut is empty, it needs to relay that information to the brain. If the gut is fighting a pathogen, it needs to relay that information as well. The links between brain and gut are immunological, hormonal, and neural with the information relayed over the central nervous system and enteric nervous system, which controls gut functioning. They are termed the gut-brain axis.