Purpose: The effect of brewers' yeast (1,3)-(1,6)-beta-D-glucan consumption on the number of common cold episodes in healthy subject was investigated.
Methods: In a placebo-controlled, double-blind, randomized, multicentric clinical trial, 162 healthy participants with recurring infections received 900 mg of either placebo (n = 81) or an insoluble yeast (1,3)-(1,6)-beta-D-glucan preparation (n = 81) per day over a course of 16 weeks. Subjects were instructed to document each occurring common cold episode in a diary and to rate ten predefined infection symptoms during an infections period, resulting in a symptom score. The subjects were examined by the investigator during the episode visit on the 5th day of each cold episode.
Results: In the per protocol population, supplementation with insoluble yeast (1,3)-(1,6)-beta-glucan reduced the number of symptomatic common cold infections by 25% as compared to placebo (p = 0.041). The mean symptom score was 15% lower in the beta-glucan as opposed to the placebo group (p = 0.125). Beta-glucan significantly reduced sleep difficulties caused by cold episode as compared to placebo (p = 0.028). Efficacy of yeast beta-glucan was rated better than the placebo both by physicians (p = 0.004) participants (p = 0.012).
Conclusion: The present study demonstrated that yeast beta-glucan preparation increased the body's potential to defend against invading pathogens.