The Influence of Long-Term Supplementation with Lactiplantibacillus plantarum LP28 on NK Cell Activity and Upper Respiratory Symptoms in Middle-Aged and Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial

In a 12-week randomized double-blind trial in 102 adults aged 50–75, Lactiplantibacillus plantarum LP28 reduced cold incidence (34.78% vs 52.00%) and increased NK cell cytotoxicity.

• Why it matters: Aging-related immunosenescence increases infection susceptibility, and evidence is needed for whether long-term probiotic supplementation can both prevent common colds and shift systemic immune biomarkers.
• What they did: Participants received 5 × 10^9 CFU L. plantarum LP28 per capsule (two capsules daily) or placebo for 12 weeks; cold incidence and WURSS symptom severity were measured alongside flow cytometry, ELISAs, and NK cytotoxicity assays.
• The result: Supplementation increased serum IL-12 and NK cell cytotoxicity while lowering CRP, implying enhanced innate immune defense and reduced systemic inflammatory stress in this middle-aged and older cohort.

AI summary of the abstract · may contain errors · not medical advice · read the paper.