Targeting the Microbiota, from Irritable Bowel Syndrome to Mood Disorders: Focus on Probiotics and Prebiotics

The crosstalk between the gut and the brain has revealed a complex communication system responsible for maintaining a proper gastrointestinal homeostasis as well as affect emotional mood and cognitive functions. Recent research has revealed that beneficial manipulation of the microbiota by probiotics and prebiotics represent an emerging and novel strategy for the treatment of a large spectrum of diseases ranging from visceral pain to mood disorders. The review critically evaluates current knowledge of the effects exerted by both probiotics and prebiotics in irritable bowel syndrome (IBS) and mood disorders such as anxiety and depression.

Relevant literature was identified through a search of MEDLINE via PubMed using the following words, "probiotics", "prebiotics", "microbiota", and "gut-brain axis" in combination with "stress", "depression", "IBS", and "anxiety". A number of trials have shown efficacy of probiotics and prebiotics in ameliorating both IBS related symptoms and emotional states. However, limitations have been found especially due to the small number of clinical studies, studies design, patient sample size, and placebo effect.

Nonetheless, current finding supports the view that beneficial manipulation of the microbiota through both probiotics and prebiotics intake represents a novel attractive strategy to treat gut-brain axis disorders such as IBS and depression.