Effect of Pleuran (β-glucan from Pleurotus ostreatus) supplementation on cellular immune response after intensive exercise in elite athletes
 
 
Journal Title (Medline/Pubmed accepted abbreviation):  Appl. Physiol. Nutr. Metab .
Year: 2010
Volume: 35
Page numbers: 755-762
doi (if applicable):  10.1139/H10-070

Summary of Background and Research Design

Background: Intense physical activity can depress the immune system. Pleuran (Imunoglukan®) is an insoluble β-glucan that is present in edible mushrooms. β-glucans are available in different varieties; some have been shown to improve the immune system in athletes while others have shown no effect.

Hypothesis/Research Question:Does intake of Pleuran β-glucan for 2 mos. affect the number of peripheral blood cells, lymphocytes, and natural killer (NK) cells after exhausting exercise in elite athletes?

Subjects: 20 winter sport athletes [9 long distance cross-country skiers, 6 figure skaters, 7 sledge (sled) sport athletes] completed the study

Experimental design:Independent groups, random assignment to groups

Treatments and protocol: Treatment: 1 capsule Imunoglukan every morning on an empty stomach for 2 mos. Each capsule consisted of 100 mg Pleuran β-glucan and 100 mg vitamin C. The placebo contained 100 mg fructose and 100 mg vitamin C. 
                To determine the individuals’ maximal oxygen uptake, participants cycled at 80 rpm with a 5 min warm-up at 100 W in 7 probands, at 150 W in 3 probands, and 250 W in 10 probands. The load was subsequently increased by 50 W every 2 min until volitional exhaustion. Venous blood samples were collected once at the start of the study and once at the end.  During the 2 mos., athletes exercised at least 3 times per week at ≤60% of their maximal oxygen uptake for at least 1 hr.
                For experimental measures, blood was acquired before and after 2 mo. supplementation, immediately after, and 1 hr after 20 min of exhaustive cycling.

Summary of research findings:
 Due to hydration during exercise, all blood cell components [erythrocytes/red blood cells, leukocytes/white blood cells, hematocrit (% of solids in the blood), and hemoglobin] increased in concentration but there was no treatment effect on these trends. Lymphocyte count was higher 1 hr after exercise for the β-glucan group (1.86 ± 0.16 x 109/L) compared to the control group (1.81 ± 0.14 x 109/L). 1 hr post-exercise, the natural killer cell activity (NKCA) dropped below baseline in the control group but not the β-glucan group. The authors suggest that the NKCA observation is positive; that the β-glucan prevents the exercise-induced immunosuppression that could lead to a chronically low immune system and therefore more susceptibility to disease.

Interpretation of findings/Key practice applications:

 Regular supplementation of Pleuran β-glucan may counteract the exercise-induced reduction of NKCA in elite athletes. Further studies are needed to support this preliminary finding.

Limitations:

This study only evaluated potential biomarkers of immune system activity. It is not known if the change in NKCA observed would actually translate to a reduction in illnesses associated with suppression of immunity. In addition, the decrease in NKCA in the placebo group was the only statistically significant treatment effect noted-none of the other blood cells were affected. Thus, it is possible that this finding represented a chance observation, as opposed to a true treatment effect.
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