Clinical Efficacy of Probiotics for Relieving Cold Symptoms in Healthy Individuals: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial.

Colds are widespread infectious diseases that affect daily life, increasing healthcare costs and limiting productivity. : The aim of this study was to investigate the effects of a dietary supplement containing specific probiotic strains ( PBS067, PBS066, BL050) on cold symptom relief, immune response enhancement, and quality of life. This randomized, double-blind, placebo-controlled trial included 65 healthy volunteers (age range: 18-44 years), divided into two groups: 40 received the probiotic treatment (with vitamins and bulking agents), and 25 received placebo (vitamins and bulking agents only) for 12 weeks. Cold symptoms and systemic inflammation were assessed at three time points (baseline T0, post-treatment T1, and 6 weeks after treatment T2). Probiotics were associated with a shorter average duration of cold symptoms (4.5 6.7% for Placebo, < 0.05). At T1, fever and muscle pain occurred in 20% of participants in the Probiotic group 28% and 44% in the Placebo group, respectively ( < 0.05 for muscle pain Placebo). For muscle pain, a trend was maintained also at T2 (17.5% 20%). The pro-inflammatory cytokine IFN-γ levels significantly decreased in the Probiotic group T0 ( < 0.0001 at T1 and < 0.01 at T2), while they increased in the Placebo group (22.279 ± 3.538 19.432 ± 3.143 pg/mL, = NS). Although not statistically significant, at T1 the Probiotic group had higher levels of IL-10 . T0 (266.98 ± 78.432 240.967 ± 70.238, pg/mL = NS). The probiotic mix effectively alleviated cold symptoms and reduced pro-inflammatory cytokine levels, suggesting anti-inflammatory effects.