In my last blog “Leaky Gut – What’s Happening?”, (Click HERE to Read) – we discussed how a myriad of health conditions are related to the health of your gut lining, but you still might be wondering how a Leaky Gut can lead to mental health concerns?
Quick reminder: An imbalanced microbiota, thinning of the mucus lining and damaged microvilli can lead to undigested particles of food and possible pathogens leaking into the bloodstream where the body will launch a pro-inflammatory attack.
Although this is a relatively new field of study and a complicated one at that – I’ll do my best to present what we currently understand about this topic in a ‘digestible’ manner – (excuse the pun). Let’s take a look at Five Ways The Gut Can Impact Mental Health:
The Vagus Nerve
The vagus nerve (it’s actually a series of nerves) connects your gut and brain. It’s through the vagus nerve that inflammation, in the form of pro-inflammatory cytokines can travel to the brain, pass through the blood brain barrier and wreak havoc on brain function, by producing chemicals that can damage mitochondrial cells (the energy centre of the cell) and microglial cells (immune cells of the brain).
Until recently it was believed that anxiety and depression contributed to gastrointestinal symptoms such as constipation, diarrhea, bloating, pain and stomach upset, but studies now show that it may be the other way around, that 90% of the information travels from the gut to the brain while only 10% goes the other way.
Hormonal
A series of hormones are released in the gut when food is ingested, some of which help to improve gut hyperpermeability (leakiness). Many of these hormones can cross the blood brain barrier and impact the regulatory centre of the brain which manages satiety and hunger. Many of these hormones also have a role in mood disorders such as anxiety and depression.
Neural (central nervous system and enteric nervous system)
If you’ve ever ‘had a gut feeling’ that’s because of the enteric nervous system (ENS), the nervous system of the gut. It’s sometimes referred to as the ‘second brain’.
Your brain has approximately 100 billion neurons, interestingly your gut contains about 500 million neurons which are connected to your brain through your central nervous system. These neurons in the gut control the motor function (digestion/absorption/elimination) of the gastrointestinal system and communicate through many neurotransmitters similar to the ones found in the brain such as acetylcholine (memory), dopamine (reward/motivation) and serotonin (mood enhancing). In fact, almost 90% of the serotonin in the body is made in the gut by immune cells with the help of gut microbes, (the microbiome). We know that the serotonin produced in the gut impacts mental health as studies show that a lack of residential microbes can negatively influence mood and behaviour.
Nutrient Deficiencies
This ‘crosstalk’ in communication between the brain and the gut is not the only way that mental health is impacted by the health of your gut lining. Important nutrients such as iron, B Vitamins, and magnesium (to name only a few) are needed to make mood enhancing neurotransmitters that support and improve brain function, mood and cognition. If the gut is leaky, it can result in a reduced ability to absorb nutrients from food and potentially result in a deficiency of much-needed brain nutrients.
In Conclusion
The science is clear, there are many ways that leaky gut is linked with brain function, can impact symptoms of ADHD and mood disorders such as depression and anxiety. The answer lies with going upstream, improving microbiome diversity, mucus lining and ultimately gut health. Lifestyle modifications (targeted nutrition, supplementation and stress management) can go a long way toward addressing the health of the gut.
Stay tuned for my next blog – “How To Fix A Leaky Gut”
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REFERENCES:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6587489/
https://www.caltech.edu/about/news/microbes-help-produce-serotonin-gut-46495
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4393509/
https://academic.oup.com/innovateage/article/3/Supplement_1/S87/5616656
https://www.sciencedirect.com/science/article/abs/pii/S0028390820301842