Efficacy and safety of Cationic Whey Protein Fraction in preventing common colds in children aged 3-7 years: A randomized, double-blind, placebo-controlled study

Introduction: Children are particularly susceptible to common cold due to their immature immune systems and frequent group exposures. A cationic whey protein fraction (IDP®) rich in lactoferrin, lactoperoxidase, and other bioactive peptides demonstrated immunomodulatory potential in preclinical studies, but clinical evidence in children is lacking. Objective: To evaluate the efficacy and safety of daily supplementation with 50 mg or 200 mg of IDP® in reducing the frequency, duration, and severity of common colds in healthy children aged 3–7 years. Methods: This randomized, double-blind, placebo-controlled study enrolled 350 healthy children aged 3–7 years (Registration number: ChiCTR2500114986). Participants were randomly assigned (1:1:1) to receive a standard IDP® dose (50 mg/day), an advanced IDP® dose (200 mg/day), or a placebo for 16 weeks. Parents completed weekly respiratory symptom questionnaires. The primary endpoints were the weekly frequency and duration of common cold episodes. Secondary endpoints included symptom severity, antibiotic use, absenteeism, and safety. Results and Discussion: After accounting for 31 dropouts, the final data set comprised 103, 107, and 109 children in the standard-dose, advanced-dose, and placebo groups, respectively. Daily supplementation with 200 mg IDP® significantly reduced the frequency and duration of common colds. Although the magnitude of benefit was smaller at 50 mg compared with 200 mg, the standard-dose group exhibited statistically and clinically relevant improvements relative to baseline and favorable trends compared to placebo, particularly in reducing cold frequency and duration during the early intervention period. Both doses of IDP® were well tolerated and had a favorable safety profile. Novelty: This clinical trial provides a novel insight into the effect of IDP® on the incidence and duration of common colds in children aged 3–7 years. The findings provide clinical evidence supporting the potential role of a cationic whey protein fraction as a nutritional intervention for respiratory health in children and provide preliminary evidence of a dose-dependent effect. Conclusion: Daily supplementation with 200 mg of IDP® cationic whey protein fraction is an effective and safe nutritional strategy for reducing the incidence and duration of common colds in children, providing a practical approach to mitigating this widespread health burden. Keywords: cationic whey protein; children; common cold; symptom; safety; randomized controlled trial