While it’s widely understood that our gut health impacts digestion, you may be unaware that your microbiome is connected to your brain. An unhealthy gut is linked to mood issues and neurodegenerative disease.

Scientists study the effect of the gut microbiome on the brain.
Scientists study the effect of the gut microbiome on the brain.
Photo Credit: National Cancer Institute

The human body contains trillions of bacteria, viruses, and fungi, which are known collectively as the microbiome.  Some bacteria are associated with disease, while many others are necessary for optimal function of the immune system, heart, and brain.

What Is the Gut Microbiome?

The term microbiome refers to all of the organisms residing in our intestines. The microbiome is considered a separate organ, and it is crucial to our health.  Most of these microbes reside in the large intestine, especially in the cecum or “pocket.”

The human body contains trillions of bacteria.
The human body contains trillions of bacteria.
Photo Credit: Unsplash

How Does the Gut Microbiome Affect the Rest of the Body?

From birth and throughout our lives, the gut microbiome controls the digestion of food, the immune system’s ability to fight pathogens, the delivery of information to the central nervous system, and many other bodily functions.

How Does the Gut Microbiome Affect the Brain?

Emerging research has shown that the gut microbiome plays a significant role in determining brain function.

Studies have demonstrated that changes in the composition of the gut microbiome influence normal physiology and contribute to inflammation and a host of diseases ranging from depression to Alzheimer’s.

Accumulating data now indicate that the gut microbiome communicates with the brain through nerve cells and various chemicals. This is known as the gut-brain axis and it influences mood and behavior.

The gut has been called the "second brain."
The gut has been called the “second brain.”
Photo Credit: Pixabay

Does Gut Health Impact the Risk of Neurodegenerative Disease ?

Scientists now think that an imbalance of the microbiome could be one of the root causes of brain dysfunction. What’s the link? An unhealthy gut produces less of the short-chain fatty acid butyrate. Less butyrate leads to increased intestinal permeability, also known as “leaky gut.”  This, in turn, triggers inflammation, which can travel throughout the body, including the brain.

When the nerves of the brain are inflamed, we are at a greater risk of depression. Gut microbiome imbalance is also linked to conditions such as autism and insomnia, both of which exacerbate emotional challenges like anxiety and depression.

The theory of a gut-brain axis suggests that by altering the balance of bacteria in the gut, we may be able to devleop therapies to treat complex central nervous system disorders.

Dr. David Perlmutter, a neurologist who has studied this issue extensively, notes in his recent book that there is a strong link between changes in the microbes of the gut and their metabolites and the risk of:

  • Alzheimer’s disease
  • Autism
  • Multiple sclerosis
  • Mood disorders

Putting It All Together

The gut microbiome acts as an organ, controlling bodily functions like digestion, immunity, and brain health.  The microbiome also with the brain, influencing its function and our behavior. As research in this area continues, we will likely discover dietary and lifestyle interventions that can favorably alter gut balance and optimize brain health.