What is the evidence for Lactobacillus (L.) Plantarum PS128 in treating medical conditions?

Evidence for Lactobacillus plantarum PS128 in Medical Conditions

There is currently insufficient evidence to recommend Lactobacillus plantarum PS128 for treating any medical condition, as it is not included in any major clinical guidelines and lacks high-quality clinical evidence supporting its efficacy for improving morbidity, mortality, or quality of life.

Current Evidence for L. plantarum PS128

The American Gastroenterological Association (AGA) clinical practice guidelines do not mention L. plantarum PS128 specifically in their recommendations for probiotic use 1, 2. The AGA guidelines only provide recommendations for specific probiotic combinations with stronger evidence bases, particularly for preventing necrotizing enterocolitis in preterm infants and for pouchitis management.

Neuropsychiatric Applications

Several small studies have investigated L. plantarum PS128 for neuropsychiatric conditions:

• A pilot study in Parkinson's disease (n=25) reported improvements in motor scores after 12 weeks of supplementation, but this was an open-label, single-arm trial without a placebo control 3
• A preliminary 8-week open trial in patients with major depressive disorder (n=11) showed decreased depression scores, but had no placebo control and found no significant changes in inflammatory markers or gut microbiota 4
• Animal studies suggest potential effects on:
  • Anxiety-like behaviors in germ-free mice with increased striatal serotonin and dopamine 5
  • Tic-like behaviors in rats via modulation of dopaminergic pathways 6

Gastrointestinal Applications

• One animal study showed L. plantarum PS128 reduced visceral hypersensitivity in a rat model of irritable bowel syndrome 7
• No human clinical trials have been published on PS128 for gastrointestinal conditions

Limitations of Current Evidence

1. Lack of high-quality human studies: Most evidence comes from small, open-label trials or animal studies
2. Absence from clinical guidelines: PS128 is not mentioned in AGA guidelines, which only recommend specific probiotic combinations with stronger evidence
3. No comparative efficacy data: No studies compare PS128 to established treatments or other probiotic strains
4. Small sample sizes: Human studies have included very few participants
5. Lack of placebo control: Available human studies lack proper placebo controls

Clinical Perspective

When considering probiotics for clinical use, the AGA recommends specific combinations with stronger evidence bases:

• For necrotizing enterocolitis prevention in preterm infants: combinations of Lactobacillus spp. and Bifidobacterium spp. (High CoE) 1, 2
• For pouchitis management: an 8-strain combination including L. paracasei, L. plantarum (not PS128 specifically), L. acidophilus, L. delbrueckii, B. longum, B. breve, B. infantis, and S. thermophilus (Very Low CoE) 1, 2

Conclusion

While preliminary research on L. plantarum PS128 shows some potential, particularly for neuropsychiatric applications, the current evidence is insufficient to recommend its use for any medical condition. Clinicians should prioritize probiotic strains and combinations with stronger evidence bases as recommended in established clinical guidelines.

For patients interested in probiotics, it would be more appropriate to consider probiotic strains and combinations that have been evaluated in larger, well-designed clinical trials and are recommended in clinical practice guidelines for specific conditions.