Psychobiotics - From Gut to Brain

Samahita Retreat offers an insight into the connection between gut health and our mental well-being. 

Probiotics are well known throughout the health and wellness community for having many benefits. Other than simply assisting the digestive system, they also impact our immune system by fighting harmful bacteria and producing antimicrobial compounds. However, it is not just the gut that is positively affected by probiotics. Studies have shown that there is a strong correlation between the positive role of gut microbes on mental health, particularly for depression, anxiety and brain-related illnesses such as Alzheimer's disease through the gut-brain-axis.

The gut-brain axis refers to the channel of communication from the gut to the brain. The microbiome within the gut communicates with the brain through the production of neurotransmitters such as serotonin, dopamine and gamma-aminobutyric acid. This is then passed through the innervation of the vagus nerve and the HPA axis.

Psychobiotics

The correlation between the brain and the gut is what can affect your mental wellbeing. When eaten, prebiotics can induce mental health benefits by preventing the circulation of pro-inflammatory cytokines. In one study it was discovered that by taking the probiotic Lactobacillus during and after pregnancy, it lowered the levels of postnatal depression.  It is also clear in other studies that probiotics improve response to stress tests and induce effects comparable to antidepressants.

Gut Microbiota Diversity

The composition and diversity of the microbiota in our gut can be improved through dietary changes alone. An example being if you eat foods such as kimchi, miso soup and water kefir  you7 will increase your guts microdiversity. In addition, eating a wide range of fibrous foods such as fruit, veg and grains will ensure a better supply of prebiotics. 

Probiotics & Prebiotics Avaliable At Samahita

After considering the benefits that probiotics can have on your mental well-being, you would then consider which specific microbes or probiotics can be used to help your mental well-being. The gut contains millions of varying strains which can not be altered outside of the body. For some probiotics that are available as supplements, it is best to search for bifidobacteria and lactobacilli, however it has also been said that prebiotics may have a greater effect. Prebiotics (non-digestible carbohydrates such as galactooligosaccharides GOS and fructooligosaccharides FOS) act as a source of nutrition for Bifidobacteria and Lactobacilli. FOS and GOS are metabolized and fermented by these microbes within the gastrointestinal tract thus increasing production of Butyrates (a short-chain fatty acid, SCFA) and the neurotransmitter gamma-aminobutyric acid (GABA)(7) among others. 

Butyrates have a varying role in the human body, one of these roles being they bolster the brain’s natural defenses by preventing breakdown of the blood-brain-barrier(BBB) and promote neurogenesis (production of neurones). This prevents the passage of pathogens and inflammatory molecules into the brain and so preventing cognitive diseases such as Alzheimer's. 

It is not fully understood why gut originated neurotransmitters are able to cross the blood-brain barrier and so the direct effect on the brain is in fact inconclusive. However, there is strong evidence on its ability to affect our moods through the HPA axis and through communication with the brain via the vagus nerve. Other studies to support the effect of GABA on mental health have shown that people suffering from depression display altered diversity and composition of gut microbiota with lower levels of GABA compared to people who are not suffering. Which is why GABA producing probiotics are seen as potential treatments for some mental health disorders.