Beverage Containing Dispersible Yeast β-Glucan Decreases Cold/Flu Symptomatic Days After Intense Exercise: A Randomized Controlled Trial
Biofortis, Mérieux NutriSciences, Addison, IL, USA
Objective: In this double-blind, randomized, placebo-controlled parallel study, we examined the effect of dairy-based beverages (250 mL/day) containing 250 mg of dispersible baker’s yeast b-glucan (Wellmune) compared to a macronutrient- and calorie-matched control on upper respiratory tract infection (URTI) in marathon runners.
Methods: Healthy adults running in the 2017 Austin Marathon consumed either b-glucan (N¼ 132) or control (N ¼ 225) for the 45 days prior to, day of, and 45 days after the marathon (91 days total). Participants completed a daily online survey assessing compliance, training status, and URTI symptoms.
Results: URTI occurrence and severity were evaluated using the Jackson Index and confirmed by the study physician. No significant differences in average duration and number of URTI episodes were found between b-glucan and control. However, those who completed the study per protocol on the b-glucan beverage reported significantly fewer URTI symptomatic days (3.43 ± 6.44 days, max 27 days) compared to those on control beverage (3.84 ± 6.84 days, max 49 days). Total URTI severity was significantly lower for b-glucan (4.52 ± 1.61) compared to control (5.60 ± 2.23). Specifically, lower (p< .05) severity ratings for nasal discharge and sore throat were reported for b-glucan compared to control. Average missed post marathon workout days due to URTI were significantly less for b-glucan (0.09 ± 0.38 days, max 2 days) compared to control (0.36 ± 1.40 days, max 10 days).
Conclusion: Overall, consumption of dairy-based beverages containing dispersible yeast b-glucan decreased URTI symptomatic days, severity of specific URTI symptoms, and missed post marathon workout days due to URTI, without affecting duration and number of URTI episodes.