Knab, A. M., Gillitt, N. D., Ciadella-Kam, L., Nieman, D. C., & Shanely, R. A. (2012). Polyphenol rich juice supplementation in Olympic swimmers does not alter inflammation or immune biomarkers. Presentation 1396 at the 59th Annual Meeting of the American College of Sports Medicine, San Francisco, California; May 29-June 2, 2012.

This study investigated the effects of consuming a juice blend made from whole fruits and vegetables on innate immunity and chronic and acute inflammation in elite swimmers training three hours per day and compared to non-athletic controls. Male swimmers (N = 9) and controls (N = 7) were recruited and compared before and after a 10-day study period. Swimmers were randomized, and completed 10 days of supplementation with or without 16 fl oz of the juice ingested pre- and post-workout, with a three-week wash out period between supplementation periods. Blood samples were taken pre-supplementation, post-10-days supplementation, and immediately post-exercise on the 10th day.

Age was not different between swimmers and controls. Swimmers were significantly fitter compared to controls. All pre-exercise measures of inflammation and immune function were not different between swimmers and controls. The patterns of change (chronic) in inflammatory cytokines and innate immune function were not different between juice and non-juice conditions over the 10-day study period. A single training bout at the end of the 10-day supplementation period caused a small but significant increase in plasma IL-6 (0.3 ± 0.1 to 0.8 ± 0.1 pg/ml with juice, and 0.5 ± 0.1 to 0.8 ± 0.1 pg/ml with no juice) and IL-10 (but not other cytokines), with no differences between juice and non-juice conditions. The training bout caused a small but significant increase in phagocytosis and oxidative burst activity, with no differences between juice and non-juice conditions.

Implication. Contrary to expectations, high-level training in elite swimmers was not associated with chronic inflammation or dysfunctional innate immunity, and acute changes post-3-hours aerobic/anaerobic training bouts were mild or indicative of immune stimulation. The mixed fruit-vegetable juice supplement is a nutritious addition to the training diet, but has no influence on inflammation and innate immune measures that could be considered already at favorable levels.

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