A dietary supplement attenuates IL-6 and CRP after eccentric exercise in untrained males

This study investigated the effects of a dietary supplement on exercise-induced markers of cell damage and the inflammatory mediators C-reactive protein (CRP) and interleukin-6 (IL-6). The supplement contained mixed tocopherols, flavonoids, and docosahexaenoate. Forty healthy, nonsmoking, untrained males (aged 18-35 yr) were randomly assigned to receive either the supplement (N = 20) or placebo (N = 20) during the 14-d experimental protocol. Blood samples were collected on day 0 (baseline), day 7 (eccentric exercise-induced injury), day 10, and day 14. Markers of cell damage (creatine kinase (CK) and lactate dehydrogenase (LDH)) and inflammation IL-6 and CRP were assessed at these time points in conjunction with subjective range of motion (ROM) and perceived pain measurements. Statistical analyses were conducted using nonparametric methods (P < 0.05). Eccentric arm curl exercise was used to induce an acute phase injury response as evidenced by significant (P < 0.0001) increases in CK, LDH, and pain, as well as a decreased range of motion 3 d after the exercise. There were no significant differences between groups in CK and LDH responses. In contrast, there were significant group differences for IL-6 (P = 0.008) and CRP (P = 0.003). At day 10, by Mann-Whitney U test of changes, the placebo group had significantly greater increases in IL-6 and CRP than the treatment group (P = 0.05 and P < 0.01), respectively. This study suggested that exercise-induced inflammation, evaluated by changes in IL-6 and CRP, was significantly reduced by the dietary supplement.