The power of the gut

Everybody’s talking about “healing the gut”, “gut health” or even “leaky gut”. Why so much talk about the gut? The importance of the gut goes far beyond the process of food going in and out. Here are a few areas which are closely impacted by the health of your gut.

The Microbiota

When referring to the gut, most people are referring to the gut microbiota, the trillions of bacteria that reside in the gastrointestinal tract. We often think of bacteria as something we want to get rid of, but when it comes to the gut, there are many bacteria that are doing wonders for our health.

Preliminary studies suggest the gut microbiota has a role in conditions ranging from intestinal motility disorders, visceral pain, depression, anxiety, Parkinson’s Disease, Alzheimer’s Disease, Multiple Sclerosis (MS), ischemic stroke, and presentation of Autism Spectrum Disorder.¹

Mental health and the gut are intrinsically linked

The bacteria in the gut have been to produce or consume an array of neurotransmitters, which are paramount for mental health.  These include dopamine, norepinephrine, serotonin and GABA.²

Serotonin, which most people recognise as our happy hormone, but plays a role in reducing anxiety, insomnia and improving feelings of self-worth, is found in abundance in the gastrointestinal tract; as much as 90-95% is found in epithelial enterochromaffin cells.³

Many bacteria have been proclaimed to produce GABA, an amino acid that functions as a main inhibitory neurotransmitter in the body, reducing feelings of anxiety.  Bacteria from both the Bifidobacterium and Lactobacillus genera, have been shown to produce GABA.  Lactobacillus rhamnosus JB-1 is the most cited as shown in mice to reduce depressive and anxiety-like behaviour with changes in cerebral GABAergic activity.⁴

Evidence is growing to show that the gut microbiota influences neurogenesis, brain development and interacts with the enteric and central nervous systems via the “gut-brain-axis”.  Preliminary studies shown that the gut microbiota influences depression, anxiety, and even Autism Spectrum Disorder.¹

Considering all of this, it should be clear that optimising gut function is crucial to optimising mental health.  Conveniently, the best way to optimise the gut microbiota is through fibrous, whole plant foods.

The gut and the immune system

Another relationship which gets a fair amount of press, is between the immune system and the gut.⁵ Not only is good digestion imperative for the absorption of the nutrients required for optimum immune health, but the integrity of the microbiome directly influences inflammation in the body and the accumulation of opportunistic, pathogenic bacteria.

A well-functioning gut mucus membrane is one of the most important defences against pathogens, and as we’ll see when we discuss intestinal permeability, a poor functioning barrier can allow bacterial endotoxins or viral fragments to pass through into the blood stream.

The gut and autoimmunity

There is a strong connection between autoimmune conditions and gut health with compromised gut function either initiating or aggravating existing autoimmune conditions.

High saturated fat and high sugar diets, or even high stress levels, or antibiotic use (though potentially life-saving when required) can lead to increased intestinal permeability (commonly known as “leaky gut”).  This leaky gut allows various proteins, bacterial endotoxins and viral fragments which are not supposed to enter the blood stream to do so leading to a myriad of health consequences.

When dairy is consumed, due to a process called “molecular mimicry”, the body can get confused and can respond by attacking the beta cells of the pancreas (as in type 1 diabetes), or it can attack the collagen in joints.  The amino acid residues 141-157 of bovine albumin are practically identical to those found in human collagen in the joints.⁶  Consequently, antibodies created to attack the cow’s milk proteins mistakenly also attack the cartilage of the joints.

A similar event takes place with Type 1 diabetes, where bovine insulin from milk can lead to antibodies which attack the pancreas.  This does not appear to hold true for A2 milk, however there are plenty of other reasons why drinking cow’s milk is far from ideal for humans.  Keep your eyes peeled for more information on why this is in future blogs.

The gut and weight loss

As we explore in detail in the vegan weight loss blog, there is a tremendous association between gut health and weight loss.

The gut microbiome can not only influence energy balance, but influence satiety and gut inflammation.  Incredibly, the Bacteroidetes taxa has been associated with reduced obesity compared to Firmicutes.  One randomised cross over trial showed a 20% increase in Firmicutes bacteria to associate with around 150 greater kilocalories absorbed, compared to a 20% increase in Bacteroidetes associating with around 150 fewer kilocalories absorbed.⁷

So now you know WHY you want to optimise your gut health, upcoming blogs with look at some specific foods and techniques you can use to optimise your gut health.

If you’re on a vegan diet and struggling with gut problems, make sure you read the upcoming blog “4 Truths and Commonly Held Misunderstandings about Vegan Gut Health”. As ever, if you want specialised, individualised help in optimising your health, feel free to check out my services page.  It would be an honour to be able to help you on your plant based journey. 💕

References

1. Strandwitz P. Neurotransmitter modulation by the gut microbiota. Brain Res. 2018;1693(Pt B):128-133. doi:10.1016/j.brainres.2018.03.015
2. Mayer EA, Knight R, Mazmanian SK, Cryan JF, Tillisch K. Gut microbes and the brain: Paradigm shift in neuroscience. J Neurosci. 2014;34(46):15490-15496. doi:10.1523/JNEUROSCI.3299-14.2014
3. Gershon MD, Tack J. The Serotonin Signaling System: From Basic Understanding To Drug Development for Functional GI Disorders. Gastroenterology. 2007;132(1):397-414. doi:10.1053/j.gastro.2006.11.002
4. Bravo JA, Forsythe P, Chew M V., et al. Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proc Natl Acad Sci U S A. 2011;108(38):16050-16055. doi:10.1073/pnas.1102999108
5. Lynch S V., Pedersen O. The human intestinal microbiome in health and disease. N Engl J Med. 2016;375(24):2369-2379. doi:10.1056/NEJMra1600266
6. Pérez-Maceda B, López-Bote JP, Langa C, Bernabeu C. Antibodies to dietary antigens in rheumatoid arthritis–possible molecular mimicry mechanism. Clin Chim Acta. 1991;203(2-3):153-165. http://www.ncbi.nlm.nih.gov/pubmed/1723358. Accessed October 20, 2018.
7. Jumpertz R, Le DS, Turnbaugh PJ, et al. Energy-balance studies reveal associations between gut microbes, caloric load, and nutrient absorption in humans. Am J Clin Nutr. 2011;94(1):58-65. doi:10.3945/ajcn.110.010132