Psychobiotics… An attractive word suggesting an improvement in mental state through the consumption of ingredients of interest. Newcomers to the world of ‘Biotics’, they are not easy to identify. How can they be defined? How do they work? What are their health benefits?
Psychobiotics: an emerging concept
It is only in 2013 that the term “psychobiotics” appears. Its creators, clinical psychiatrist Professor Ted Dinan and neuroscientist Professor John Cryan, define it as “live organism that, when ingested in adequate amounts, produces a health benefit in patients suffering from psychiatric illness”. At that time, they were only applying the definition to a subset of probiotics.
Subsequently, scientists proposed to expand their definition in 2016 to include any other substance that may modify the microbiome for the purpose of improving mental health, even indirectly. According to these new data, this would now include :
- Prebiotics, capable of promoting the growth of bacteria conferring mental health benefits. Among them, FOS, GOS…
- Synbiotics, combining pre- and probiotics with psychobiotic potential.
In addition, it was also envisaged to extend it to food supplements, antibiotics, antipsychotics, physical exercise… or any other parameter that would be able to act on “psychiatric” effect bacteria.
However, current studies seem to focus mainly on psychobiotic pre- and probiotics.
What are their mechanisms of action?
Not all prebiotics and probiotics can claim to be psychobiotics. Indeed, psychobiotic bacteria produce and stimulate specific molecules that manipulate signals between the gut and the brain via the vagus nerve, to help improve the psychological profile of consumers. However, the mechanisms of action are not yet fully understood. Nevertheless, they are believed to be able to produce and metabolise a wide range of :
- Neurotransmitters, such as serotonin, gamma-aminobutyric acid, dopamine, noradrenaline and acetylcholine;
- Neuroactive substances, such as melatonin, kynurenic acid and quinolinic acid;
- Cytokines (increase anti-inflammatory and reduce pro-inflammatory);
- Short-chain fatty acids: propionate, butyrate, lactate, acetate.
These actions can also be achieved indirectly through the consumption of prebiotics, by increasing the growth of commensal bacteria that influence the mental state.
What are the interests of psychobiotics?
Psychobiotics have significant therapeutic potential. Acting on the bacteria responsible for mental health could optimise the management of mental disorders and illnesses, ranging from simple mood swings to serious diseases such as Parkinson’s or Alzheimer’s.
Thus, scientific evidence points to their benefits in the case of disorders:
- Psychological: mood swings, stress, anxiety, depression, insomnia;
- Neurodevelopmental: autism, attention deficit hyperactivity disorder (ADHD), Tourette’s syndrome;
- Neurodegenerative: Parkinson’s disease, Alzheimer’s disease
To conclude, psychobiotics are of real therapeutic interest in the field of mental health. Recent publications provide encouraging results, opening up the hope of an improvement in psychological disorders through the manipulation of the intestinal microbiota, a key player in gut-brain communication. Further studies on the subject are obviously expected to clarify the modes of action of these promising pre- and probiotics.
LC
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