Background: The purpose of the present investigation was to determine the effects of EPA/DHA supplementation on resting and exercise-induced inflammation and oxidative stress in exercise-trained men. Fourteen men supplemented with 2224 mg EPA+2208 mg DHA and a placebo for 6 weeks in a random order, double blind cross-over design (with an 8 week washout) prior to performing a 60 minute treadmill climb using a weighted pack. Blood was collected pre and post exercise and analyzed for a variety of oxidative stress and inflammatory biomarkers. Blood lactate, muscle soreness, and creatine kinase activity were also measured.
Results: Treatment with EPA/DHA resulted in a significant increase in blood levels of both EPA (18 +/- 2 micromol x L(-1) vs. 143 +/- 23 micromol x L(-1); p < 0.0001) and DHA (67 +/- 4 micromol x L(-1) vs. 157 +/- 13 micromol x L(-1); p < 0.0001), while no differences were noted for placebo. Resting levels of CRP and TNF-alpha were lower with EPA/DHA compared to placebo (p < 0.05). Resting oxidative stress markers were not different (p > 0.05). There was a mild increase in oxidative stress in response to exercise (XO and H2O2) (p < 0.05). No interaction effects were noted. However, a condition effect was noted for CRP and TNF-alpha, with lower values with the EPA/DHA condition.
Conclusion: EPA/DHA supplementation increases blood levels of these fatty acids and results in decreased resting levels of inflammatory biomarkers in exercise-trained men, but does not appear necessary for exercise-induced attenuation in either inflammation or oxidative stress. This may be due to the finding that trained men exhibit a minimal increase in both inflammation and oxidative stress in response to moderate duration (60 minute) aerobic exercise.