By the end of the trial, the participants’ job stress scale had reduced significantly from 71.67 to 63.33, with a p-value of 0.003.
Their perceived stress scale scores also decreased by more than 20 per cent as compared to the baseline.
The trial was conducted by Bened, a Taiwan firm that specialises in psychobiotics – probiotics that address mental wellbeing. Researchers from the MacKay Medical College, MacKay Memorial Hospital, Taipei Veterans General Hospital were also involved in this study.
Bened’s flagship strain, Lactobacillus plantarum PS128, isolated from spontaneously fermented mustard greens, has previously been shown to benefit children with autism spectrum disorder, triathletes, and patients with major depressive disorder.
This time round, the probiotic was tested in IT professionals who perceived themselves to be under high stress due to the nature of their work. The IT professionals with a perceived stress scale of 27 or higher were recruited into the study.
This study is part of a larger trial, where the researchers also examined the efficacies of Bened’s other psychobiotics PS128, PS23, and PS23 on reducing stress and mood symptoms among high stress nurses.
Writing in the Frontiers in Nutrition, the researchers found that Lactobacillus plantarum PS128 supplementation in IT professionals could provide stress and gastrointestinal symptoms relief.
The open-label, single-arm, baseline-controlled study recruited IT professionals from a particular company located in Northern Taiwan, with 32 completed the study.
Subjects had to take two capsules containing PS128 powder, equivalent to a daily intake of 20bn CFU, for eight weeks.
They had to answer a questionnaire assessing their perceived stress scale, job stress scale, quality of life etc before and after the trial.
Their biological samples, such as their salivary levels of stress biomarkers, namely cortisol, beta-amylase, immunoglobulin A, lactoferrin, and lysozymes were also measured before and after the trial.
Supplementation of the psychobiotic was found to reduce insomnia and bring about positive mood, and this was correlated by a reduction in the subjects’ salivary amount of the stress hormone cortisol.
Findings showed that the subjects’ insomnia severity index (ISI) decreased from the mean baseline of 12.83 to 8.94 after the trial.
The researchers highlighted that the reduction in insomnia was accompanied by an actual drop in their salivary amount of cortisol, the stress hormone.
At baseline, the highest cortisol level amongst the subject was more than 0.8 μg/dL, but by the end of the trial, it was below 0.8 μg/dL, with more subjects having cortisol amount below 0.4 μg/dL.
“Our finding that the reduction in insomnia severity was complemented by the decrease in salivary cortisol levels, which might indicate possible correlations between probiotic use and sleep improvements through the HPA axis,” the researchers said.
The decrease in cortisol level was also associated with an increase in positive emotions when subjects assessed their quality of life before and after the trial.
“It has been suggested that possible mechanisms for the positive effects of probiotics on the CNS may include their ability to regulate mood or emotions by influencing the HPA axis, altering neural signaling pathways, or CNS neurotransmitters levels of serotonin and gamma-aminobutyric acid (GABA), or regulating inflammatory or immune responses by the gut microbiota.”
However, apart from cortisol, all other stress- and anxiety-related biomarkers, such as such as α-amylase, IgA, lactoferrin, and lysozyme were not significantly altered after the intervention.
“The lack of a significant change in objective measures of stress, including IgA, lactoferrin, lysozyme, or attentional performance after probiotic treatment might indicate other underlying mechanisms that we were unable to determine in the current study.
“Explanations for our findings may be restricted by the small sample size and the open-label design, and future investigations that assess more objective biological plasma biomarkers or brain imaging studies are warranted,” the researchers said.
Another finding was that the psychobiotic had improved gastrointestinal symptoms.
For instance, there was better appetite and lower incidence of constipation and diarrhoea.
The score for decreased appetite lowered significantly from a mean of 2.50 to 1.33, with a p-value of 0.019.
The incidence of constipation and diarrhoea also reduced from 2.86 to 2.06 and 2.78 to 1.36, with a p-value of 0.010 and 0.002 respectively.
For future studies, the researchers suggested that larger-scale randomised, placebo-controlled trials will be required.
Source: Frontiers in Nutrition
Psychobiotic Supplementation of PS128TM Improves Stress, Anxiety, and Insomnia in Highly Stressed Information Technology Specialists: A Pilot Study.
Authors: Ying-Chieh Tsai and et al