Sixty nine adults completed a randomized, double blind, placebo controlled trial of 30 billion CFU per day of Pediococcus acidilactici PA53 for eight weeks, out of 75 enrolled.
The headline outcomes were psychological, with a reported 13% improvement in happiness scores and 23% in sleep quality, but the gut endpoints were the cleaner ones: gastrointestinal symptoms down 9.5% and Bristol Stool Scale consistency improved 28%, all as reported.
IL-6 and TNF-alpha fell significantly and IL-25 rose significantly. In 16S microbiota data, Ruminococcus roughly doubled (1.1% to 2.2%) while Blautia (7.6% to 11.4%) and Faecalibacterium (6.9% to 10.6%) each rose by around half, as reported.
The numbers
| GI symptoms, as reported | 9.5% reduction |
| Stool consistency, Bristol Stool Scale, as reported | 28% improvement |
| Happiness and sleep quality, as reported | 13% and 23% improvement respectively |
| Cytokines, as reported | IL-6 and TNF-alpha decreased significantly; IL-25 increased significantly |
| Microbiota genera, as reported | Ruminococcus 1.1% to 2.2%; Blautia 7.6% to 11.4%; Faecalibacterium 6.9% to 10.6% |
What this does not show
- That the numbers are verified. Every figure comes from trade reporting; the published abstract could not be opened during the sweep. The same reporting gives an age range of 55 to 70 and a mean age of 54.4, which cannot both be right, a basic inconsistency that is reason to distrust the secondary numbers generally.
- That the mood effects are solid. The authors state not all psychological measures reached significance, and with this many outcomes the multiple comparisons question is obvious. No correction is mentioned in the reporting.
- What a 28% stool consistency change means. Percentage improvements on ordinal scales such as the Bristol Stool Scale are close to meaningless without baselines and absolute values.
- Anything about athletes. Healthy older adults, not athletes, not under exercise stress. Nothing here transfers to exercise induced GI symptoms without an argument.
- A functional gut effect. Genus level 16S shifts are not evidence of function. No metabolite or short chain fatty acid data appear in the reporting.
- Anything about other strains or products. One strain at one dose for eight weeks, with no dose response and no durability data. Probiotic results do not transfer across strains or to other gut products.
Caveats worth holding
- Verification limit: all figures come from trade reporting of the paper. PubMed was CAPTCHA walled and Europe PMC rate limited by the time this item was worked, so the published abstract could not be opened. Verify every number before use.
- The reported age range (55 to 70) and mean age (54.4) are mutually inconsistent, which undermines confidence in the secondary numbers generally.
- The strain supplier provided product and placebo. Independence of funding, data control and publication decisions is claimed, which is the right disclosure, but the relationship exists, and the coverage sits inside a promotional cycle around the supplier.
- Multiple psychological outcomes with no correction mentioned; the authors state not all reached significance.
- Healthy older adults, single strain, single dose, eight weeks; no dose response, no durability, no athlete relevance.