A Double-Blind, Randomized, Placebo-Controlled Nutritional Study Using an Insoluble Yeast Beta-Glucan to Improve the Immune Defense System

Abstract

Purpose: In a placebo-controlled, double-blind, randomized clinical trial, the effect of an insoluble yeast beta-glucan preparation on the incidences of common colds and its effect on common cold symptoms were compared to placebo. Methods: 100 healthy participants with recurring infections were randomly assigned to receive either placebo or yeast beta-glucan (Yestimun®; n = 50 each group) over a period of 26 weeks. The subjects had to document each common cold episode in a diary, and rate 6 predefined infections symptoms on a 3-point rating scale during an infection period, resulting in an infection score. The common cold episodes were confirmed by the investigators. Results: A total of 171 common cold episodes were documented. Of these, 76 were experienced by 38 subjects in the beta-glucan group and 96 were experienced by 48 subjects in the placebo group (p = 0.406). The beta-glucan group had significantly more subjects without incidences of common cold than the placebo group (15.6% vs 2.0%; p = 0.019). During the most intense infection season (first 13 weeks of the study), the beta-glucan group had significantly less infections compared to placebo (p = 0.02). Beta-glucan significantly reduced the typical cold symptoms (“sore throat and/or difficulty swallowing”, “hoarseness and/or cough” and “runny nose”) as opposed to placebo. Conclusion: The present study demonstrates a prophylactic effect of yeast beta-glucan on the occurrence of common colds as opposed to placebo. In addition, when these episodes occurred, they were from the beginning less pronounced and subsided faster

Effects of orally administered yeast‐derived beta‐glucans: A review

“…Orally administered Y‐BG seems to be well tolerated in healthy subjects . For short‐term treatment at doses of up to 400 mg daily, there were no changes in biochemical‐ or hematological parameters or on heart rate and blood pressure .…”

“…Six of the studies are addressed to effects on upper respiratory tract infections (URTI) . Following heavy exercise, athletes are susceptible to URTI due to a weakened immune system.…”

“…However, during the common cold period, 13 weeks from November to March, authors reported lower total number of infections in the beta‐glucan group (per protocol [PP] population) compared to the placebo group,( p = 0.045). The average number of infections was 29% lower in the beta‐glucan intention to treat population (ITT) compared to the placebo group ( p = 0.022) . The study, however, suffered from several drawbacks; it was not based on a sample size calculation, there was no adjustment for multiple testing and the definition of ITT did not seem to follow the predefined definition, since drop‐outs during intervention were excluded from ITT and were higher in the glucan group ( n = 5) compared to the placebo group ( n = 1).…”

“…After 180 days given 900 mg daily, clinical parameters such as body weight, temperature, heart rate, and blood pressure did not change significantly in healthy subjects, and adverse events reported were considered unlikely connected to beta‐glucan intake . Two cases of rashes and one with gastric pressure were probably related to Y‐BG intake .…”

The Common Cold: Potential for Future Prevention or Cure

“…Beta-glucans are natural polysaccharides of the cell walls of Saccharomyces cerevisiae, fungi and some bacteria and they seem to have immunostimulatory effects [109]. In two recent trials they were able to reduce the occurrence of symptomatic common cold infections and reduced severity [109,110].…”