Lost in translation? The potential psychobiotic Lactobacillus rhamnosus (JB-1) fails to modulate stress or cognitive performance in healthy male subjects.
Level 2 - randomized trial
Randomized, placebo-controlled crossover clinical trial in humans
PubMed 27865949 · doi:10.1016/j.bbi.2016.11.018
What was done
An 8-week randomized, placebo-controlled, crossover trial evaluated the effects of the putative psychobiotic Lactobacillus rhamnosus (JB-1) in 29 healthy male volunteers. Researchers evaluated self-reported stress, mood, anxiety, sleep quality, cognitive performance (visuospatial memory, attention switching, rapid visual information processing, emotion recognition), resting EEG, plasma cytokines (IL-10, IL-1β, IL-6, IL-8, TNFα), TLR-4-stimulated cytokine release, and salivary cortisol and subjective stress during a socially evaluated cold pressor test (SECPT).
What was found
The abstract reports no exact numerical values or effect sizes. Lactobacillus rhamnosus showed no significant differences compared to placebo on mood, anxiety, baseline stress, sleep quality, subjective stress or HPA axis response to the SECPT, cognitive metrics, EEG patterns, or basal and stimulated cytokine levels.
Why it matters
Despite robust preclinical evidence showing stress reduction and central GABA receptor changes in mice, this strain failed to demonstrate psychotropic or anti-inflammatory effects in healthy human participants, underscoring translational barriers in microbiome research.
Limits
The sample size was small (n = 29) and restricted strictly to healthy males, precluding assessment in females or clinical cohorts with existing anxiety, mood, or stress-related disorders where baseline dysregulation might allow therapeutic effects to emerge.
Cited by
- contradicts Lactobacillus rhamnosus probiotic strains have been shown to reduce anxiety in human clinical trials.