The Connection Between Gut Microbiota and the Human Brain

What Is gut microbiome?

Gut microbiota is a complex community of micro-organism species that live within the digestive tract. It is the largest reservoir of micro-organisms mutual to both humans and animals. The Gut microbiome consist of as many as 1,000 types of bacteria. The microbiome also consists of as many as 10 times the amount of cells and roughly as many as 150 times as many genes as the human genome contains. The microbiome has a symbiotic relationship with its human host and it co-evolves. The gut microbiome is a finely tuned eco-system, but its development depends on a number of factors, such as:

  • If a person is subject to anti-bodies
  • The food a person consumes
  • Infections
  • Which micro-organisms a person absorbs from the mother’s birth-canal at birth
  • Stress
  • Genetic predisposition

Studies have shown that gut microbiota is involved in the regulation of many brain functions, such as:

  • Anxiety
  • Pain
  • Cognition
  • Mood

The intestinal microbiome is in place at birth. It is initially influenced by the delivery and feeding, and reaches a mature adult like state within the first few years of life.

The influence of the brain by gut microbiota

An increasing amount of research suggests, that the importance of the gut-brain axis for neurology and indicates that the triggers for a number of neurological diseases may be located in the digestive track. It is possible that the gut microbiome may in fact, influence the central nervous system as well as the development of the nerve cells and the immune system. The gut brain axis refers to signaling taking place between the gastrointestinal tract and the nervous system.

The Human gut microbiome is the aggregate of gut micro-organisms, consisting of all of its bacteria, archaea, viruses, and fungi. It has previously been thought that the connection between the microbiome and the possibility that it could also be responsible for processes outside of the digestive tract, were unimaginable. However, more and more studies are revealing more in depth detail on the matter. While scientist are working to prove the connection, it has been proven that the gut and the brain do in fact communicate. They do this through multiple routes, such as, the vagus nervous system, the immune system, the enteric nervous system and by way of the microbial metabolic system. An example of the gut and the brain communicating, is the intestinal bacteria converting carbohydrates into short chain fatty acids, in order to strengthen the connection of the cells and reinforce the blood brain barrier. The blood brain barrier serves as a cell based wall to protect the brain from inflammation and infections.

Many of the studies involving the link between gut microbiota and the brain, are influenced by Autism spectrum disorder. Research shows that approximately 90% of children diagnosed with autism spectrum disorder also have severe to moderate gut issues. Studies have shown that those with Autism, had far fewer types of bacteria, thus making the gut more vulnerable to attack for disease causing pathogens. Studies have also noted that there was a difference in the bacteria found of those with Autism Vs. those without. Discovering the connection between gut microbiota and the brain could help researches discover what causes Autism and how to treat it in the future.

Microbiome’s role in regulating the brain process

Neurologist firmly believe that the gut microbiome regulates important brain processes that are necessary to the development of neurological diseases. The scientific research being conducted on gut microbiome is, in all possibility, a door to discovering the cure for Multiple Sclerosis. The gut brain axis is an emerging concept that could lead to developing new therapies and treatments for central nervous system disorders by modifying the gut microbiota. The possibilities for evolving medical care are endless within the research of gut microbiota and the brain.

The studies conducted are done so using germ free animals. The study then compares the germ free animals to normal animals that were later exposed to pathogenic bacterial infections, probiotic bacteria and antibiotic’s. Scientist then compare the differences of many aspects and functions in order to report data and gain further information on the gut microbiota and brain function.

Gut microbiotas ability to communicate with the brain and effect behaviors is a progressive concept. Microbiota interacts with the host forming essential relationships that govern homeostasis. Despite the unique bacterial combination of each individual, there seems to be, a specific balance to reach in order for it to be beneficial to our health. It is also suggested, that a decrease in the desirable gastrointestinal bacteria will lead to deterioration in the gastrointestinal neuroendocrine, or immune relationships and lead to disease.


Some research has suggested that probiotics, such as those found in yogurt, may alter the signals from the gut to the brain when you are afraid or anxious. Studies have shown a dampened response from people with depression, they exhibited muted response in areas involving processing and sensation. The long term goal of studies such as this, is to determine if taking probiotic supplements or eating probiotic yogurt, regularly can have a positive effect on the balance of bacteria in your gut and possible alter emotional responses to negative situations. Like most areas focusing on the study of microbiota and the human gut, far more research is still needed and quite possibly, under way.

The range of diseases linked to gut microbiota is vast, some of the effected diseases could range from autoimmune disease, metabolic disease, gastrointestinal disease, brain disorders, type 2 diabetes, psychiatric disorders and autism spectrum disorder, just to name a few. That’s not even counting the other effects that microbiota could possibly have on the body such as: mood, learning, emotion, appetite, satiety, and memory. The growing research that is being directed at microbiota and its connection to the human brain could help provide many answers, therapies, and possibly even cures for an outstanding amount of diseases and illnesses. The further research and scientific findings are a great achievement for the scientific community and could mean many helpful steps forward for the coming generations. Understanding how microbiota can affect our brain and contribute to so many diseases and changes in the human body is a very hot topic across the scientific community and we can expect to see more and more research and findings, as the curiosity continues to grow.


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