Respiratory tract infections (RTI) represent the most common cause of sickness in children, especially in those who live in area with extreme contaminations of the environment, such as coal mine, heavy chemical industry and power stations, and high contamination particles from car exhausts due to high frequency of automobile traffic.
It has been well known that strennious physical challenge might suppress immune mechanisms and result in higher risk of respiratory infections, which are a direct result of the lower activity of immune cells (such as macrophages and natural killer cells), antigen presentation and other immune mechanisms.
In recent years, large number of studies has been published on the effect of beta-glucans, the natural polysaccharides isolated from yeast. The current evidence suggests that beta-glucans has significant effects on non-specific immunomodulation.
In a randomised, double-blind, placebo-controlled clinical trial, scientists evaluated the effect of yeast beta-glucans in 77 children (average age = 10 yrs) with chronic respiratory problems. These children were randomly assigned to receive either a beta-glucan (100 mg/day) or a placebo for 4-week duration. Saliva IgA (sIgA) level, and physical activity using a 6-minute walking test were measured before and after the 4-week supplementation.
The study found that children in the beta-glucan supplement group had a significant increase in walking distance when compared with those in the placebo group, and this improvement is also more significant in girls than boys.
Although there was no significant change in sIgA levels in children who took beta-glucan for 4 weeks, the sIgA levels are significantly lower in children taking a placebo.
Therefore, short-term oral supplementation with yeast beta-glucan improves physical endurance in children with respiratory problems, and helps their mucosal immunity via stabilization of the sIgA levels.
Source: Josef Richter J. et al. Ann Transl Med 2015; 3(4):52