Journal Title (Medline/Pubmed accepted abbreviation): Eur. J. Appl. Physiol.
Page numbers: 2033-2040
doi (if applicable): 10.1007/s00421-011-1837-z
Summary of background and research design:
Background: High frequency, high intensity physical activity can suppress the immune system and make a person more susceptible to disease. β-Glucans are dietary fibers that include specific linkages between the glucose molecules. They are found naturally in foods including yeast, grains, and some mushrooms, and have shown to enhance immune functions.
Research question: Does β-glucan supplementation reduce the incidents of upper respiratory tract infections (URTIs) and/or impact immunological parameters in athletes?
Subjects: Males (n = 26) and females (n = 24) from 7 different sports were recruited from the Slovokian National Sports Centre.
Experimental design: random, double-blind, placebo-controlled design
Imunoglukan® (pleuran): 200 mg β-glucan + 200 mg vitamin C per day
Placebo: 200 mg vitamin C per day
Protocol : The athletes were randomly assigned to one of the two treatment groups. They consumed the supplement for 3 mos. The participants completed questionnaires regarding illness symptoms related and unrelated to URTIs (nasal congestion, fatigue, etc.) before intervention, after intervention, and 3 mos following intervention.
Summary of research findings:
- Pleuran significantly reduced URTI symptoms during the 3 mo of intervention compared to pre-intervention and the 3 mos post-intervention. The placebo showed a slight but non-statistically different reduction in symptoms.
- Phagocytosis, which is the act of the immune system engulfing foreign cells, was reduced 5% with the placebo but not with pleuran. This implies that the immune system was reduced slightly in the placebo group.
- Pleuran supplementation significantly increased natural killer (NK) cell count compared to pre-intervention and the placebo, implying a more active immune system.
Key practice applications:
Supplementation of 200 mg pleuran per day may attenuate the susceptibility of athletes to infections.
Vitamin C was included both the pleuran supplement and in the placebo. It is unknown what benefits the supplement could impart without vitamin C. Also, because a non-athletic control group was not part of this study design, it is unknown if the supplement acted against exercise-induced immunosuppression, immunosupression in general, or both.