Do you know that human adult gut is populated by 10–100 trillion microbes that encapsulate approximately 150 times more genetic material than the human genome itself. Yes! It’s shocking! Now there is increasing evidence that gut microflora can influence the brain, but the scientists still figuring out how they do it. They do know however that regular intake of probiotic (good bacteria) reduces levels of anxiety and depression-like behavior. They believe that good bacteria are capable of inducing changes in the GABAergic system in regions of the brain that are known to be involved in modulation of moods and behaviors.
What are psychobiotics?
Psychobiotics are live bacteria (probiotics) which, when ingested, confer mental health benefits through interactions with commensal gut bacteria. This also includes prebiotics, which enhances the growth of beneficial gut bacteria. Psychobiotics exert anxiolytic (anti-anxiety) and antidepressant effects characterized by changes in emotional, cognitive, systemic, and neural indices. Bacteria–brain communication channels through which psychobiotics exert effects include the enteric nervous system (Gut-Brain Axis) and the immune system.
The bacteria most frequently exploited as probiotics are the Gram-positive Bifidobacterium and Lactobacillusfamilies. Bifidobacteria and Lactobacilli do not possess pro-inflammatory lipopolysaccharide chains, and so their presence and colonization in the gut do not trigger inflammatory action of our immune system nor cause infections. It should be noted, however, that Gram-positive bacteria are not always beneficial, and some species, such as the Clostridia family, may be pathogenic.
What is Microbiome-Gut-Brain Axis (“The Gut Feeling”)
The gut microbiome comprises all microorganisms inhabiting the intestinal tract. Gut–brain axis through early colonisation and through which the brain and gut jointly maintain an organism’s health.
A pivotal study found that mice raised in sterile environments (lacking indigenous bacteria) showed exaggerated physiological reactions to stress compared to normal controls. The abnormal reactions were reversible through probiotic-induced bacterial recolonization.
Gut bacteria have since been found to participate in the regulation of varied and important physiological processes, including immunomodulation (regulation of immune response against invaders), adiposity (regulation and distribution of fat tissue in the body), and metabolism as well as the modulation of nervous system in the gut.
What are the clinical experiments to support the benefits of probiotics on anxiety and depression? – “In the pursuit of happiness”
Most studies are based on rodent models to induce life stress and behavioral changes. Findings of the studies are summarized below;
Probiotics increase production of Serotonin (“Happy Hormones”) (Journal of Psychiatric Research, 2008) – Sprague-Dawley rats treated for 14 days with Bifidobacteria infantis have higher level of the serotonergic precursor, tryptophan by bifidobacteria treatment, provides encouraging evidence in support of the proposition that this probiotic may possess antidepressant effects.
Probiotics vs. Antidepressant Study (Neuroscience, 2010) – Probiotic Bifidobacterium infantis supplementation in rats (maternal-separation model) normalizes the anxiety and depressive behaviours in the rats and the effects of probiotics were noted to be comparable to effects of citalopram (anti-depressant).
Probiotics effects on brain (National Academy of Sciences of the United States of America, 2011) – Rats fed with Lactobacillus rhamnosus showed fewer depressive and anxious behaviours. These changes were accompanied by a blunted corticosterone response to stress, suggesting that the probiotic downregulated HPA-axis activity. Probiotics differentially altered expression of inhibitory GABA receptors in specific brain areas via Vagus Nerves (nerves that connect the gut to the brain).
Probiotics reduce anxiety and improve learning (The Sages College, New York, 2013) – Healthy mice fed Mycobacterium vaccae displayed reduced anxiety in a maze-learning task. Probiotic-fed mice completed the maze faster and with fewer errors, The benefits persisted at 1 week, but not 3 weeks, after supplementation.
Any latest Human Researches?
Fermented milk drink containing Lactobacillus casei Shirota (Yakult, Japan) vs. placebo -supplementation resulted in significantly more participants self-rating as happy rather than depressed, relative to placebo (European Journal of Clinical Nutrition, 2006).
In conclusion, there are significant benefits of probiotics in improving the moods and reducing anxiety levels, therefore next time instead of binging on alcohol, try probiotic drink instead. Try to consume probiotics daily and consistently either by consuming probiotics yogourt, yogourt drink or even taking the capsule of probiotics daily. Dairy free-options includes Kefir and fermented vegetables such as Kimchi.
Enjoy and “Chillax” the healthy way!