N-3 polyunsaturated fatty acids do not affect cytokine response to strenuous exercise

Abstract

The aim of the present study was to investigate whether fish oil supplementation was able to modulate the acute-phase response to strenuous exercise. Twenty male runners were randomized to receive supplementation ( n = 10) with 6.0 g fish oil daily, containing 3.6 g n-3 polyunsaturated fatty acids (PUFA), for 6 wk or to receive no supplementation ( n = 10) before participating in The Copenhagen Marathon 1998. Blood samples were collected before the race, immediately after, and 1.5 and 3 h postexercise. The fatty acid composition in blood mononuclear cells (BMNC) differed between the fish oil-supplemented and the control group, showing incorporation of n-3 PUFA and less arachidonic acid in BMNC in the supplemented group. The plasma levels of tumor necrosis factor-α, interleukin-6, and transforming growth factor-β1 peaked immediately after the run, the increase being 3-, 92-, and 1.1-fold, respectively, compared with resting samples. The level of interlukin-1 receptor antagonist peaked 1.5 h after exercise, with the increase being 87-fold. However, the cytokine levels did not differ among the two groups. Furthermore, supplementation with fish oil did not influence exercise-induced increases in leucocytes and creatine kinase. In conclusion, 6 wk of fish oil supplementation had no influence on the acute-phase response to strenuous exercise.