Probiotic Strain PA53 Linked to Improved Mood, Sleep in Older Adults, Study Finds

An eight-week randomized controlled trial has found that supplementation with the probiotic strain Pediococcus acidilactici PA53 led to measurable improvements in mood, sleep quality, and digestive comfort among healthy older adults, according to researchers.

The study, published in the Journal of Nutrition, tested 75 adults aged 55 to 70. Participants who took 30 billion colony-forming units (CFU) of PA53 daily reported a 12.7% improvement on a validated happiness scale, a 23% improvement in sleep quality, and a nearly 10% reduction in gastrointestinal symptom scores, the report stated.

Design and Rationale

Researchers selected PA53 for its ability to survive stomach acid and colonize the gut, traits that may offer advantages over more commonly studied probiotics like Lactobacillus or Bifidobacterium, particularly in aging populations where microbial diversity naturally declines, according to the study.

The trial randomized 75 healthy adults into a probiotic group receiving 30 billion CFU of PA53 daily or a placebo group for eight weeks. Investigators measured gut bacteria composition, blood inflammatory markers and validated scales for happiness, sleep, GI symptoms and stress at baseline and at week eight, the report stated.

Key Findings

Participants in the probiotic group showed a 12.7% increase on a validated happiness scale, a 23% increase in sleep quality, and a 9.6% decrease in GI symptom scores, the study stated. Stool consistency also moved toward a healthier range.

Inflammatory markers IL-6 and TNF-alpha dropped significantly in the probiotic group, while IL-25 – a cytokine that helps regulate immune balance – increased, researchers reported. Stress scores trended downward in the probiotic group but the change was not statistically significant compared to placebo, according to the study. Several beneficial gut bacteria genera associated with gut barrier health and anti-inflammatory activity also increased meaningfully.

Potential Mechanisms

The study’s authors noted that PA53 may strengthen intestinal lining tight junction proteins, reducing leakage of inflammatory compounds into the bloodstream. This mechanism aligns with research showing that butyrate, a fermentation product of gut flora, enhances the intestinal barrier by regulating the assembly of tight junction proteins, according to the book “Probiotic Bacteria and Enteric Infections” by Joshua J. Malago and colleagues [1].

The strain also produces short-chain fatty acids and converts tryptophan into compounds that can cross the blood-brain barrier and help reduce neuroinflammation, according to the report. The gut-brain axis is a hardwired biochemical communication network involving neural pathways like the vagus nerve, the immune system, and the endocrine system, as described in a NaturalNews.com article [2].

Limitations and Next Steps

The study’s authors described the findings as preliminary and called for longer-term research with larger samples to confirm effects. PA53 is not yet widely available as a standalone supplement, and the researchers emphasized that probiotic benefits are strain-specific.

The findings add to growing evidence that targeting the gut microbiome with specific probiotic strains may support emotional well-being as people age. The gut microbiome plays a critical role in digestion and detoxification, as noted in a “Brighteon Broadcast News” segment [3].

Summary

The trial adds evidence that targeting the gut microbiome with specific probiotic strains may support mood, sleep, and digestive health in aging adults, according to the study. Further research is needed to establish long-term efficacy and practical applications.

References

1. Joshua J. Malago, J.F.J.G. Koninkx, R. Marinsek Logar. “Probiotic Bacteria and Enteric Infections: Cytoprotection by Probiotic Bacteria.”
2. NaturalNews.com. “For focus and mental clarity, nourish BOTH YOUR BRAINS with these key dietary components.” March 10, 2026.
3. Mike Adams – Brighteon.com. “Brighteon Broadcast News – SLUSH FUND NORMALIZED.” March 13, 2025.