One hundred patients with mild knee osteoarthritis were randomized to receive Latilactobacillus sakei LB-P12, 10 billion CFU once daily (n=50), or identical placebo (n=50) for 12 weeks. The primary outcome was change in total WOMAC; secondary outcomes included WOMAC subscales (pain, stiffness, function), VAS pain, inflammatory markers (CRP, ESR, IL-1β, IL-6, TNF-α), COMP, radiographic joint space width, and EQ-5D-5L. Outcomes were assessed at baseline and 12 weeks, with per-protocol as primary and ITT as supportive analyses. Overall, the results showed greater improvement with LB-P12 for WOMAC total and subscales, larger reductions in VAS pain, a greater decrease in IL-1β, and a relative preservation of EQ-5D-5L versus placebo; safety signals were absent. These findings suggest that LB-P12 may modestly reduce symptoms and systemic IL-1β in mild knee OA, warranting confirmation in larger, longer trials.