How intestinal microbes can affect the brain

We hold 2 to 2.5 kilos of microbes in our gut, there are more microbes in our gut than there are cells in our bodies.

We have a symbiotic relationship with our microbes, they keep us healthy by influencing almost every hormone in the body, providing chemicals such as histamine. Histamine is a powerful neurotransmitter, water regulator and is used by immune cells to combat infection. Our microbes also prevent toxins and pathogens from causing damage to the intestinal wall, which can lead to inflammation and leaky gut.

Cells lining the intestines are in what is called tight junctions. Chemicals, pathogens and foods such as gluten in wheat and other grains can damage the tight junctions, prizing them apart, causing what is commonly known as leaky gut. When this happens toxins and undigested particles of food enter the bloodstream and cause toxicity in the body including the brain.

Gluten can be especially problematic. Gluten breaks down into a morphine like structure called Gluteomorphins. When there is gut permeability Gluteomorphins can leak from the gut into the blood stream. Milk can also break down into casomorphins if it cannot be broken down by the intestinal bacteria. These morphine-like structures fit into opioid receptors in the brain, which can cause an addiction. Research on casomorphins has shown that this opioid is an antagonist to serotonin O. Yu. Sokolov et al, meaning that a high level of casomorphin will displace serotonin making it deficient in the brain. Considering that gluteomorphin attaches to the same receptor sites, it is possible that it has same antagonistic effect. 90 percent of serotonin is made in the gut. Serotonin is known as the happy hormone, it is used by the brain and a deficiency is believed to be a major cause of depression.

Any toxins and pathogens that enter through the mouth will also have an impact when there is dysbiosis (imbalance of gut microbes). The stomach contains hydrochloric acid which kills some unwanted pathogens. When there is dysbiosis there is usually exceptionally low hydrochloric acid in the stomach. Because of this many pathogenic bacteria survive the stomach, creating more dysbiosis. Pathogenic bacteria produce toxins when they die or excrete their wastes, when there is leaky gut these toxins enter the blood stream and negatively affect the brain. Research by Nicole J.YangIsaac M.Chiu has shown that bacteria can negatively affect the central nervous system. Probiotic bacteria protect the gut wall by preventing toxins and pathogens from reaching it.

Our gut microbes are in direct contact with the brain through the vagus nerve. Messages are sent from the brain through the vagus nerve to the gut, and messages from the microbiome (gut bacteria) are sent to the brain. If you have an abundance of pathogens in the gut and very little probiotic bacteria, the signals to the brain will be altered which can lead to mood disorders Paul Forsythe et al.

Alcohol in the form of ethanol and acetaldehyde is made in the gut when there is an overgrowth of yeast. These forms of alcohol are very toxic and can cause inebriation with physical symptoms. Damage to the brain from these toxins can result in lack of self-control, problems with co-ordination, impaired speech development in children, retardation, aggression, stupor and loss of memory. As alcohol molecules are very small, they can penetrate most barriers in the body Dr Natasha Mc bride Page 52.

Psychological problems such as autism, ADHD, schizophrenia, dyslexia, dyspraxia and other brain related problems have a strong link to gut dysbiosis Dr Natasha Mc bride Page 50.

There is a strong link between antibiotic exposure effecting the microbiome, leading to altered brain function, with symptoms ranging from anxiety and panic to major depression, psychosis and delirium. One antibiotic course can increase risk for depression and anxiety, rising with multiple exposures G B Rogers et al.

Recent research has shown associations between the gut microbiome and dementia. This research has also suggested a link to amyloid deposition, a strong risk factor for Alzheimer’s disease Naoki Saji et al.

If you are experiencing any of these problems a protocol can be personally designed for you to heal your digestive tract. Please get in touch with me using the contact form on my web site juliehowesnutrition.com.

References in chronological order

O. Yu. Sokolov, N. A. Pryanikova, N. V. Kost, Yu. A. Zolotarev, E. N. Ryukert & A. A. Zozulya Reactions between β-Casomorphins-7 and 5-HT2-Serotonin Receptors, Accessed online https://link.springer.com/article/10.1007/s10517-006-0030-6 Published November 2005

Nicole J.YangIsaac M.Chiu Bacterial Signaling to the Nervous System through Toxins and Metabolites https://www.sciencedirect.com/science/article/abs/pii/S0022283617300141 10 March 2017

Paul Forsythe 1, John Bienenstock, Wolfgang A Kunze, Vagal Pathways for Microbiome-Brain-Gut Axis Communication, accessed online https://pubmed.ncbi.nlm.nih.gov/24997031/ Reviewed in 2014

Dr Natasha Mc bride, p52, Alcohol intoxication, Book; Gut and psychology syndrome, Printed July 2014 by Medinform publishing.

Dr Natasha Mc bride, p50, Psychological problems, Book; Gut and psychology syndrome, Printed July 2014 by Medinform publishing.

G B Rogers,1,* D J Keating,2 R L Young,3 M-L Wong,4 J Licinio,4 and S Wesselingh From gut dysbiosis to altered brain function and mental illness: mechanisms and pathways Accessed online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4879184/ Published online 2016

Naoki Saji, Kenta Murotani, Takayoshi Hisada, Tadao Kunihiro, Tsuyoshi Tsuduki, Taiki Sugimoto, Ai Kimura, Shumpei Niida, Kenji Toba & Takashi Sakurai Relationship between dementia and gut microbiome-associated metabolites: a cross-sectional study in Japan https://www.nature.com/articles/s41598-020-65196-6 Published online 18th of May 2020