The dose dependent effects of polyphenol supplementation on inflammatory markers following eccentric exercise
MetadataShow full item record
Unaccustomed eccentric exercise can lead to decreases in muscle force production, increases in soreness, swelling, stiffness, and discomfort. The purpose of this study was to test the dose response of pomegranate juice concentrate on serum markers of muscle permeability, inflammation, and total anti-oxidant status. To test this hypothesis, 45 healthy recreationally active males (22.3 ± 0.5 y, 73.8 ± 1.71 kg, 174.9 ± 0.9 cm) were recruited from the local Austin community for participation in this study. Subjects were disqualified from participation in the study if in the past 6 months they were engaged in an exercise training program. Subjects were placed into either the placebo group, the once-daily, or twice-daily pomegranate juice concentrate supplementation group. Subjects performed a total of 8 days of supplementation. On day 4, all subjects came to the laboratory and underwent an eccentric exercise protocol consisting of 2 minutes of downhill running at -10% grade at 7.5 mph repeated 10 times, resulting in ~20 minutes of total downhill running. Thereafter, subjects performed 50 eccentric elbow extensions each lasting 5 seconds using a weight equal to their concentric one-repetition maximum. Blood measures were made pre-exercise (baseline), and 2, 24, 48, 72, and 96 hours post exercise and analyzed for interleukin-6, creatine kinase, myoglobin, and total anti-oxidant status. Creatine kinase was significantly elevated at 96 hours post exercise, but with no significant differences between treatments. Myoglobin was significantly elevated above baseline at 2 and 96 hours, but with no differences between treatments. There was no effect for time or treatment on the total anti-oxidant status of the serum. Il-6 was significantly higher at 2 and 24 hours after exercise, but with no difference between treatments. The percent increase in interleukin-6 from baseline was significantly lower in the twice-daily POM supplementation group versus placebo (124.3 ± 9.4, 188.6 ± 16.0% of baseline; respectively) during the 2-96 hours following eccentric exercise, but no statistical difference between 1x and 2x or 1x and placebo was observed. This suggests that 8 days of supplementation with pomegranate juice concentrate twice a day significantly reduces the percent increase in a marker of inflammation (interleukin-6) during the 96 hours following eccentric exercise; however, neither supplement was different than the placebo in regards to all other measures.