According to a new study published this week ahead of print by the British Journal of Nutrition1, Institut Rosell-Lallemand probiotic formula Probio’Stick® (a combination of Lactobacillus Rosell-52 and Bifidobacterium Rosell-175), significantly alleviates psychological distress in volunteers. These results are supported by a pre-clinical behavioural study also described in the same publication, demonstrating the anxiolytic-like effects of Probio’Stick® in rats. In a previous randomized study, Probio’Stick® was shown as the first probiotic preparation to efficiently reduce stress-induced gastrointestinal symptoms in chronic stress sufferers 2.

The clinical study was supervised by the team of Drs Messaoudi and Bisson in Nancy (France). It assessed the effect of one-month Probio’Stick® administration on anxiety, depression, stress and coping strategies in healthy human volunteers, using a range of psychological self-assessment tests and a biomarker for stress and anxiety (24 hour urinary free cortisol monitoring). The study involved 55 healthy stressed subjects in total.

The randomised study showed that one month daily administration of Probio’Stick® preparation (equivalent to 3X109 CFU/day) had a beneficial effect on general signs of anxiety and depression (in particular the somatisation, depression and anger-hostility components, as shown by Hopkins Symptom Checklist-90,  an instrument used to evaluate a broad range of psychological problems and symptoms of psychopathology).

The probiotic also improved the subject’s ability to cope with the stress of everyday’s life events (The Ways of Coping Checklist). Results of the self-assessment tests were correlated by a decrease of urinary free cortisol levels in the probiotic treated group, a biomarker for stress and anxiety. The investigators reported that it was the first time that free cortisol level was monitored during a probiotic clinical study.

The pre-clinical study that was described in the same publication was based on a rat model of anxiety which is commonly used to screen anxiolytic agents. After two weeks treatment, Probio’Stick® showed a significant anxiolytic-like effect, comparable to that of Diazepam which was used as a positive control.

The researchers commented:
Consumption of Probio’Stick mitigated psychological distress in three tests without displaying any adverse event. These results provide further evidence that gut microflora plays a role in stress, anxiety, and depression, perhaps via the enteric nervous system as well as centrally. Subject to the confirmation of these results, probiotics might offer a useful novel therapeutic approach to neuropathologic disorders and/or as adjunct therapies in psychiatric disorders.

A few months ago, another innovative pre-clinical study was presented by Professor Guy Rousseau at the New York Academy of Science. This behavioural study, performed in rats, showed the positive effects of the same probiotic preparation (Probio’Stick®) on behavioural signs of depression following myocardial infarction.

Possible modes of actions
Three different mechanisms have been invoked to explain the beneficial effects of probiotics on anxiety and depression:

1) Competitive exclusion of gut pathogens by the probiotics (certain gut pathogens produce substances shown to induce anxiety and aggression in animals, e.g. propionic acid).
2) Decrease in pro-inflammatory cytokines (a link has been drawn between depression and high levels of certain inflammatory markers).
3) Direct communication with the central nervous system via vagal sensory fibers, leading to changes in neurotransmitter levels or function.

The authors explain that it has been shown in the past that both Lactobacillus Rosell-52 and Bifidobacterium Rosell-175 exert anti-inflammatory properties on human intestinal epithelial cells3.

Moreover, Lactobacillus Rosell-52 was also recently demonstrated to protect the gut microflora against the invasion of pathogenic bacteria and both strains are well known to reduce intestinal permeability thanks to their “barrier effect” 4.
The combination of these actions could lead to reduce the inflammation and neuro-inflammation caused by stress at the level of the gut mucosa and may explain the clinical effect of Probio’Stick® on both physical and psychological symptoms of stress.

1. Messaoudi M., Lalonde R., Violle N., Javelot H., Desor D, Nejdi A., Bisson J.-F., Rougeot C., Pichelin M., Cazaubiel M. And Cazaubiel J.-M.: Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and humans. Br J Nutr. 2010 Oct 26:1-9.
2. Diop L., Guillou S., Durand H. : Probiotic food supplement reduces stress-induced gastrointestinal symptoms in volunteers: A double-blind, placebo-controlled, randomized trial.  Nutrition Research Volume 28, Issue 1, January 2008. Pages 1-5.
3. Wallace TD, Bradley S, Buckley ND, et al. (2003) Interactions of lactic acid bacteria with human intestinal epithelial cells: effects on cytokine production. J Food Prot 66, 466-472.
4. Wine E, Gareau MG, Johnson-Henry K, et al. (2009) Strain-specific probiotic (Lactobacillus helveticus) inhibition of Campylobacter jejuni invasion of human intestinal epithelial cells. FEMS Microbiol Lett 300, 146-152

Taken from material provided by the Institut Rosell

First Published October 2010

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