A Probiotic to Reduce Physiological Effects of Stress and Anxiety: Clinical Trial Results

Today’s good news is brought to you by researchers in Finland and Germany who are looking for natural means of alleviating the development of mood and stress-related disorders.[i]  I don’t know about the rest of you, but I sure as hell could use some improvement in my current stress levels!

The opening paragraph of the paper points out that while short-term stress is a “beneficial adaptation” to normal stressors, chronic stress is a whole different story:  it is a “…major risk factor for the development of a wide range of physical and mental disorders.”  How about this for a staggering statistic?  According to the American Psychological Association, as of 2018, nearly 75% of adults in the country experience at least 1 physical or emotional stress in the last month, and about 50% of people report stress levels higher than what is regarded as acceptable.  And that was before COVID!

The authors assert that the evidence supporting the connection between the gut  microbiota and health is “overwhelming.”  Lacticaseibacillus paracasei, formerly known as Lactobacillus paracasei, has shown promise in previous studies in preventing chronic stress-associated behaviors from developing.

This double-blind, placebo-controlled clinical trial was conducted on 117  healthy adults, aged 18 through 45, who were broken up into groups, one control, one treatment.  The experimental group received 1.75 billion (low potency – I am not sure why as there’s no explanation given) units of a very specific strain of the probiotic Lacticaseibacillus paracasei  (Lpc-37) one time per day for 5 weeks.  The primary goal was to see if the probiotic affected heart rate in response to a stress test but they also looked at different biomarkers and self-reported symptoms.

The results are interesting.  LPC-37 reduced heart rate in those with low levels of chronic stress but strangely, it was significantly higher in those with high levels of chronic stress.  In the discussion section, they authors state that they cannot as yet explain the phenomenon. The probiotic also had no effect on salivary cortisol level, which is a marker for stress and actually, the probiotic had little effect in many of the parameters being tested but in looking at certain subgroups, clinically significant differences were noted.  For example,  during the stress testing, blood pressure in the women in the experimental group increased markedly less than those in the placebo arm.  Why?  No one knows yet.   Two more notes of interest on the results:  the probiotic did significantly reduce the “perceived exhaustion/fatigue” in response to the stress test in those with low levels of chronic stress.  This may be related to the reduced heart rate also seen in this group.  Also, the Lpc-37 significantly decreased blood pressure (both diastolic and systolic) in those with high levels of stress and in women.  In previous research, which I have covered (see here), this probiotic has been shown to decrease blood pressure after 4 weeks of treatment.

So even more good news on the targeted probiotic front.  It really does feel like some progress is being made.


[i] Patterson, E, Griffin, SM, Ibarra, A, Ellsiepen, E, Hellhammer, J. Lacticaseibacillus paracasei Lpc-37 improves psychological and physiological markers of stress and anxiety in healthy adults: a randomized, double-blind, placebo-controlled and parallel clinical trial (the Sisu study). Neurobiology of Stress. 2020:13.   https://doi.org/10.1016/j.ynstr.2020.100277

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