A daily probiotic powder taken for six months improved memory and thinking scores in older adults with early memory problems, and lowered a blood marker linked to Alzheimer's, in a small placebo-controlled trial. Researchers say it's early, but it adds to evidence that gut health affects your brain.

r/science (shared by u/mvea) reports: a small placebo-controlled trial shows that daily intake of a specific multi-strain probiotic powder (code KL-P301, containing three strains: Bifidobacterium longum subsp. animalis, Lactobacillus fermentum, and Lactobacillus brevis) for six months improved memory and thinking scores in older adults with early memory problems, and reduced an Alzheimer's-related blood biomarker (plasma pTau181). The comments section is abuzz: u/5H17SH0W lists the three strains, u/TolerableSimulacra and others share personal improvement experiences with fermented foods/kefir, u/Status-Secret-4292 raises concerns about patenting of strains and accessibility, and u/Justkeepbreathing123 calls for stronger supplement regulation in the US. On the facts: the study is indeed a real double-blind RCT: Seo et al., based on the Korean GARD cohort, 87 participants (probiotic 40/placebo 47) completed 24 weeks; the probiotic group showed a significant drop in plasma pTau181 (p<0.001) and CDR improvement, published in 2026 in the Journal of Alzheimer's Disease (medRxiv preprint doi:10.64898/2026.02.01.26345102). On the speculative level, this is a preliminary positive signal in an early (prodromal) population, not evidence of a cure; moreover, the paper is a preprint and needs to await peer review and validation in larger samples.

Checked 🔗 Needs re-verification: the study is real — Seo