Carbohydrate supplementation during intense exercise and the immune response of cyclists

• Published in: Clinical nutrition (Edinburgh, Scotland) Scotland), 2002-10, Vol.21 (5), p.423-429
• Main Authors: BACURAU, R.F.P., BASSIT, R.A., SAWADA, L., NAVARRO, F., MARTINS, E., COSTA ROSA, L.F.B.P.
• Format: Article
• Language: English
• Subjects: Adult; Analysis of Variance; Antibody Formation - immunology; Biological and medical sciences; Blood Glucose - immunology; carbohydrate supplementation; Carbohydrates; cortisol; Cross-Over Studies; cyclist; Cytokines - blood; Cytokines - immunology; Dietary Carbohydrates - administration & dosage; Dietary Carbohydrates - immunology; Dietary Supplements; Exercise - physiology; Exercise Test; Fundamental and applied biological sciences. Psychology; glutamine; Glutamine - blood; Glutamine - immunology; Humans; Hydrocortisone - blood; Hydrocortisone - immunology; immunodepression; Insulin - blood; Insulin - immunology; Lactic Acid - blood; Lactic Acid - immunology; Male; Metabolisms and neurohumoral controls; Sweat - immunology; Sweat - physiology; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Weight Loss - immunology; Weight Loss - physiology
• ISSN: 0261-5614; 1532-1983
• DOI: 10.1054/clnu.2002.0576

Objective: To evaluate the effect of carbohydrate supplementation upon some aspects of the immune function in athletes during intense indoor cycling. Methods: Twelve male athletes cycled for 20 min at a velocity corresponding to 90% of that obtained at the anaerobic threshold and rested for 20 min. This protocol was repeated six times. The athletes received, during the trial, water ad libitum, or a solution of carbohydrate (95% glucose polymers and 5% fructose) at 10% (w/v), 1 g kg h every 20 min, starting at the 10th minute of the first exercise period, plus extra water ad libitum. Results: Exercise induced a reduction in peripheral blood mononuclear cell proliferation (37%) as well as in the production of cytokines by cultured cells (interleukin-1 (IL-1), interleukin-2 (IL-2), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), by 37%, 35%, 26% and 16%, respectively). All of these changes were prevented by the ingestion of a carbohydrate drink by the athletes, except that in IFN-γ production, which was equally decreased (17%) after the second trial. The concentration of plasma glutamine, an important fuel for immune cells, was decreased in the placebo group but maintained in the group that received carbohydrate. Conclusion: Carbohydrate supplementation affects positively the immune response of cyclists by avoiding or minimizing changes in plasma glutamine concentration.