The gut-brain connection is something that’s been talked about for thousands of years since Hippocrates said ‘all disease begins in the gut’. However it’s only been in the last two decades, if that, that we’ve really seen science come to the table with strong evidence of the positive effect that probiotics & improved gut health can have on the functioning of the brain. 

As I’m often fond of saying, your gut is like a central dashboard within the body, communicating constantly with various extensions such as your immune system, your nervous system, your skin, your heart & of course your brain. If you have imbalances or malfunctions in that central dashboard, you can expect malfunctions in the parts reliant on the proper functioning of it (i.e. the aforementioned list). Correct the initial malfunction at the source & expect better functioning along the line, so to speak. 

Now, with so many studies pointing to the gut as the source of our ailments, it is important to put into perspective why this seems to be the case. And it would seem, through logic, that if so many people (supported with studies) are benefiting from taking probiotics or making positive alterations to gut function, it would suffice to say that so many people are out of balance in the gastrointestinal tract. Remember that nature always strives for balance in the first place so arguably depression, anxiety & mood swings are not intended in any way but rather come as a result of an imbalance somewhere in the body. 

This begs the question then, why are we so out of balance? 

One could not look past our frivolous use of antibiotics over the past 80 years as being the main culprit of such an imbalance. Antibiotics, as we well know, not only kill off pathogenic microbes but also beneficial ones – the first to grow back in most cases? The pathogenic species. The unfortunate thing about antibiotics (which have been life saving in many cases) is that we now have a population who’s microbiomes (those microbes we talked about) are completely & permanently altered. We don’t really know what an ideal microbiome is anymore – all we know is that ours have changed completely since the use of antibiotics & we are seeing a huge rise in disease as a result.

When it comes to microbes & our brains the science is quite clear – microbes manufacture our brains most important chemicals known as neurotransmitters within the gastrointestinal tract – up to 90% of them in fact. So that serotonin you’ve been wanting, that dopamine to help you feel happy & that all important melatonin to help you fall asleep are all dependent on gut microbes – interesting huh? 

Another factor in the gut-brain connection, it seems, is the management of inflammation by the actions of gut microbes & the immune system. Our gut bugs are literally talking with our immune cells, teaching them from the first time you enter the world how to behave cordially & appropriately. Naturally, if our gut bugs are imbalanced, we can experience numerous immunological challenges. This, according to the research, seems to stem from increased intestinal permeability, a situation where the thin membrane of the gut (used for diffusing nutrients from the gut into the blood) becomes too leaky & open. This is akin to a fly screen with large holes & tears in it; it doesn’t exactly work. Alongside macromolecules of food, pathogenic microbes & other such intruders now in the bloodstream, a specific marker has been noted to be particularly damaging on the body and brain & that is LPS – lipopolysaccharide. LPS has been found to be in extremely high levels in Alzheimer’s disease & is known to cause neuron damage in the brain. 

These factors may be extremely instrumental in the development of such mental illnesses as depression, anxiety & mood swings as the brain becomes inflamed & less capable of processing information. In fact this has been supported with studies where researches have administered probiotics to mice & noted striking differences in behaviour – mice who receive probiotic treatment & then experience stressful situations report less cortisol development (a stress hormone) & bhevaiourally seem to be ‘more chilled’. Further, this experiment has been replicated in humans where probiotic treatment regularly reduces qualitative anxiety scores.

Dr Natasha Campbell-McBride goes as far as saying that Autism is the manifestation of a gut which has become a source of toxicity instead a source of nutrition during developmental years. According to her, if the condition is treated early enough the autistic symptoms can be reversed. This opinion is supported by research which shows that autistic children are regularly found to have different gut microbes to their healthy counterparts, specifically having higher levels of microbes like E.coli & clostridia.

SO what does all this mean?

It means that if we want to experience great mental health, then considering an approach which looks at the gut might be a good move. By taking a sensible, long-term approach such as taking probiotics regularly & eating a wholefoods, high fibre diet, both of which support gut-health, may be the key in attaining a more balanced brain.

I would also say that this research suggests that we may heighten our respect for the human body which seems to respond well to holistic treatment available from nature. As science continues to uncover the specifics of disease & the microbiome, & how we can pinpoint specific bugs for specific conditions, expect huge improvements in the symptom-based approach of western medicine.

But also expect some interesting products entering the market from big-pharma…because you can’t patent naturally occuring microbes 😉


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Sources for this article include 

Jones, N. (2011). Friendly bacteria cheer up anxious mice. Nature.

Perlmutter, D. (2008). Neuro-Inflammation Induced By Lipopolysaccharide Causes Cognitive Impairment Through Enhancement Of Beta-Amyloid Generation. [online] David Perlmutter M.D. Available at: 

ScienceDaily. (2016). Do microbes control our mood?. [online] Available at: [Accessed 24 Oct. 2016].

Disclaimer: Remember to always work with your well qualified, nutritionally-versed practitioner when it comes to the management & treatment of illness. The information contained on this page is for informational purposes only & should not be considered medical advice.