Supplements of Lactobacillus casei strain Shirota may ease
symptoms of anxiety in people with chronic fatigue syndrome
(CFS), according to new research funded by Yakult.
Two months of supplementation with the bacterial strain from
a sachet was associated with a decrease in anxiety symptoms,
according to findings published in the open-access journal Gut
These results lend further support to the presence of
a gut-brain interface, one that may be mediated by microbes
that reside or pass through the intestinal tract, wrote
the authors, led by Venket Rao from the University of Toronto.
The researchers admitted the research was preliminary and raises
many questions regarding the mechanism of action. The
results of the present study should be viewed simply as a stimulus
for further research, they added.
The study was described as interesting by probiotic
expert Professor Gregor Reid from the Canadian R&D Centre
for Probiotics at the Lawson Health Research Institute, and
The University of Western Ontario. He also agreed that the study
raises many questions.
Do the gut microbiota (and probiotics) influence energy
levels (which our own studies of HIV patients indicates is true)
and by doing so is there an indirect effect on the brain and
perception of how we feel? Do probiotics cause direct gut to
brain signaling or indirectly via alterations in the overall
microbiota that influence serotonin uptake? The latter seems
unlikely as depression per se was not altered, Prof Reid
The Toronto-based researchers recruited 39 CFS patients and
randomly assigned them to receive daily supplements of either
Lactobacillus casei strain Shirota (24 billion colony forming
units) or placebo for two months.
At the end of the study, the researchers reported significant
increases in the faecal levels of both Lactobacillus and Bifidobacteria
in people receiving the bacterial strain, compared to placebo.
A significant reduction in the symptoms of anxiety was also
recorded in the Lactobacillus group.
Follow-up studies with probiotics should further examine
specific gut microbes, intestinal structure and function as
well as physiological markers associated with anxiety and depression,
wrote the researchers. These may include inflammatory
cytokines and other immune chemicals, blood tryptophan levels
and urinary metabolites of neurotransmitters.
Commenting on the findings, Professor Reid added: I hope
the researchers study each subject to try to understand when
changes in anxiety occurred, what the triggers were and if these
triggers occurred while on probiotics or placebo.
Information from responders and non-responders could
provide valuable insight into how real these findings are, and
how confirmatory studies should be designed, he said.
Commenting on the study, Dr Kudo, chief of science at Yakult
Europe told NutraIngredients.com: "This is a very interesting
study exploring how the axis between the gut and brain can affect
health and mood. Positive outcomes were shown for chronic fatigue
sufferers taking Lactobacillus casei Shirota (the probiotic
strain in Yakult). A previous study in the UK with our strain
also reported an association between consumption of this probiotic
and improved mood in certain subjects.
It should be noted that this was a pilot study but the
results certainly indicate the need for further research in
this area, and highlight the wide-ranging potential benefits
that come from good gut health.
This area of enteric neuroscience, which will be discussed
further in June at the international Yakult symposium in Amsterdam,
is very exciting. Prof. Bienenstock from McMaster University
of Canada will discuss how the gut microbiota works together
with the brain and nervous system to promote health and well-being.