What Does the Intestine Have to do with the Brain?
Lined by 100 million nerve cells, the human gut is practically a brain of its’ own. The gut communicates with the brain often through the release of chemical mediators into the bloodstream. Recent studies show that the gut is connected directly to the brain through neural circuits and is therefore able
to transmit information to the brain in mere seconds. This connection is what is popularly referred to as the gut brain axis. The gut is able to tell us how hungry we are, why we shouldn’t have one more pizza or why it craves so much for juice at a specific time. The gut is able to transmit signals rapidly to the brain through the gut brain axis. The gut brain axis controls anxiety and is best demonstrated in the phrase “butterflies in the belly.”
The connection between your intestines and your brain is both hormonal and neural. Your body has a central nervous system which comprises the brain and the spinal cord. The digestive tract has its own nervous system called the intrinsic nervous system. Communications between these two systems are often referred to as the gut-brain-axis. Scientists believe these communications account for some of the impairment observed in both the gut and the brain during certain disease states. The gut-brain axis is also the primary site exploited for treatment of many disease conditions including obesity, nutritional deficiencies, eating disorders, depression, autism and several bowel syndrome.
How the Brain is Connected to the Intestines
The intestines are linked to the brain through a neural circuit that transmits signals up to the brain and down to the gut in seconds. The intestine also has connections with the brain through the endocrine system and the gut microbiome.
- Vagus Nerve Stimulation: Out of the twelve cranial nerves, there is one – vagus nerve – that runs all the way to the intestines. The vagus nerve brings commands from the brain that regulate secretions in the gut in response to various stimuli. Also, specialized cells that line the walls of the intestines send signals to the vagus nerve when they are stimulated by food nutrients.
- Microorganisms in the Gut: The intestinal tract contains trillions of microorganisms. Different strains of bacteria secretes chemicals called neurotransmitters which send signals to the nervous system. Certain species of bacteria help reduce stress and improve memory. This is the basis for faecal transplant.
- Hormones in the Gut: The presence of certain food types in the intestinal tract stimulate the secretion of hormones like cholecystokinin which is responsible for satiety. Also, serotonin, a hormone responsible for “good mood”, is produced more than ninety percent of the time in the gut.
The Gut-Brain Axis and Disease
Scientists now believe there is more than a passing relationship between the state of a person’s gastrointestinal tract and the person’s overall health. By paying attention to our gut, we can improve our health in predictable ways.
▪ Inflammatory Bowel Syndrome (IBS): This is a condition affecting the intestines which makes them inflamed. Scientists now have evidence to show that IBS results from disruption of the intestinal microbial flora. In the intestinal tract of every individual, there are bacteria that begin to grow from the person’s birth. These bacteria are not harmful in the gut where they live. Rather, they confer a number of benefits on their host. They aid absorption of nutrients and protect the intestinal walls from being colonized by harmful bacteria. As useful as this community of bacteria is, it varies from one person to another and is grossly interfered with throughout a person’s lifetime. Consumption of antibiotics, infections in the gut and other conditions alter the nature and concentration of the organisms. Major upsets in the balance of the bacteria in the gut is said to cause IBS as well as changes in a person’s mood.
▪ Autoimmune Diseases. Scientists believe that disruption in the microbiome of an individual’s gut can lead to autoimmune diseases. Changes that alter the bacterial flora can lead to leaky gut with harmful microorganisms and their products invading the enteric nervous system and causing an alteration in the functioning of the body’s immune system. This alteration leads to autoimmune diseases in which the body’s immune system attacks its own tissues by mistaking them for foreign tissues. Studies have associated altered gut microbiome with Alzheimer’s disease, Parkinson’s disease, multiple sclerosis and cerebrovascular disease.
▪ Diet Modification: A person’s diet interferes significantly with the microbial composition of the person’s gut. Dietary intake of fermentable foods is especially noted to alter people’s microbiome. These foods include wheat, honey, milk and onions. A reduction in their consumption coupled with an increased intake of fibre-rich foods and probiotics is known to improve the symptoms in people with IBS.
▪ Minimal Antibiotics Consumption: Consumption of certain drugs like NSAIDs can lead to the destruction of the gut mucosa. Restricting antibiotic consumption to only when specifically prescribed by your doctor is a good habit that will limit alterations in the composition of your microbiome. Practices that facilitate the destruction of the microbial lining of your gut are not to your benefit.
▪ Stress Management: Physical and psychological stress have been found to affect the composition of the gut microbiome. There are therapies in place to help with stress management which have shown improved symptoms in persons with IBS.
The gut-brain axis is an important part of the intrinsic nervous system. Good habits like adequate night rest, regular exercise, and consumption of healthy food, fruits and fresh water would help maintain the smooth relationship between the gut, its environment and the brain. 80% of disease proliferation begins with the gut, therefore, you need a balance in the gut-brain axis to remain healthy and happy at all times. A health gut is a healthy you!
Understanding the Basics of the Gut-Brain Connection. Retrieved from https://dukeintegrativemedicine.org/DHWBlog/understanding-the-basics-of-the-gut brain-connection/
Linda Said. (June 16, 2020). How to Improve the Gut-Brain Connection: 4 Ways to Keep Retrieved from https://www.goodpath.com/learn/gut-brain-connection
Pedro, M. B. and Egberto, R. B. (August 7, 2020). The Gut Brain-Axis in Neurological Diseases. Retrieved from https://www.scielo.br/scielo.php?pid=S2359-56472020000500528&script=sci_arttext