Influence of a polyphenol-enriched protein powder on exercise-induced inflammation and oxidative stress in athletes: a randomized trial using a metabolomics approach

Abstract

Objectives: Polyphenol supplementation was tested as a countermeasure to inflammation and oxidative stress induced by 3-d intensified training.

Methods: Water soluble polyphenols from blueberry and green tea extracts were captured onto a polyphenol soy protein complex (PSPC). Subjects were recruited, and included 38 long-distance runners ages 19-45 years who regularly competed in road races. Runners successfully completing orientation and baseline testing (N = 35) were randomized to 40 g/d PSPC (N = 17) (2,136 mg/d gallic acid equivalents) or placebo (N = 18) for 17 d using double-blinded methods and a parallel group design, with a 3-d running period inserted at day 14 (2.5 h/d, 70% VO2max). Blood samples were collected pre- and post-14 d supplementation, and immediately and 14 h after the third day of running in subjects completing all aspects of the study (N = 16 PSPC, N = 15 placebo), and analyzed using a metabolomics platform with GC-MS and LC-MS.

Results: Metabolites characteristic of gut bacteria metabolism of polyphenols were increased with PSPC and 3 d running (e.g., hippurate, 4-hydroxyhippurate, 4-methylcatechol sulfate, 1.8-, 1.9-, 2.5-fold, respectively, P<0.05), an effect which persisted for 14-h post-exercise. Fatty acid oxidation and ketogenesis were induced by exercise in both groups, with more ketones at 14-h post-exercise in PSPC (3-hydroxybutyrate, 1.8-fold, P<0.05). Established biomarkers for inflammation (CRP, cytokines) and oxidative stress (protein carbonyls) did not differ between groups.

Conclusions: PSPC supplementation over a 17-d period did not alter established biomarkers for inflammation and oxidative stress but was linked to an enhanced gut-derived phenolic signature and ketogenesis in runners during recovery from 3-d heavy exertion.

Trial registration: ClinicalTrials.gov, U.S. National Institutes of Health, identifier: NCT01775384.

Conflict of interest statement

Competing Interests: Mary Ann Lila has a 6% equity in the Nutrasorb company (i.e., the company supplying the product for this study). The Rutgers University patent number for the Nutrasorb supplement is: PCT/US2011/28347. METHODS OF OBTAINING NATURAL PRODUCTS FROM COMESTIBLE FLUIDS AND METHODS OF USE. Provisional Application Filing date: March 15th 2010. PCT filed March 14th, 2011. Entered national phase September 2012. Kirk L. Pappan is an employee of Metabolon, Inc. Nicholas D. Gillitt and Fuxia Jin are scientists for Dole Foods, the company that funded the study. There are no further patents, products in development or marketed products to declare. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials.

Figures

Figure 1. Subject flow diagram.

Figure 2. Serum 12,13-hydroxyoctadec-9(Z)-enoate (DHOME) (time effect, P

For all figures: PSPC = red bars; placebo = gray;+ = mean; ____ = median; ○ = extreme data points; box = upper and lower quartiles; whiskers = maximum and minimum of distribution; * = group contrast difference P<0.05. The vertical axis represents the median scaled intensity.

Figure 3. Serum cortisol (time effect, P

Figure 4. Serum 3-hydroxybutyrate (group contrast at 14-h recovery, P = 0.005, Q = 0.246).

Figure 5. Serum acetoacetate (group contrast at 14-h recovery, P = 0.0105, Q = 0.265).

Figure 6. Serum hippurate (interaction effect, P = 0.0245; group contrasts immediately- and 14-h-post-exercise, P = 0.006 and 0.022, respectively; Q = 0.116 and 0.2648, respectively).

Figure 7. Serum 4-methylcatechol sulfate (interaction effect, P = 0.0017; group contrasts 14-days supplementation, P = 0.002, and immediately- and 14-h-post-exercise, P

Figure 8. Serum 4-hydroxyhippurate (interaction effect, P = 0.0014; group contrast immediately-post-exercise, P = 0.0014).

Figure 9. Serum cinnamoylglycine (interaction effect, P = 0.0017; group contrasts immediately- and 14-h-post-exercise, P = 0.008 and 0.009, respectively; Q = 0.1421 and 0.265, respectively).

Figure 10. Serum arabinose (interaction effect, P

Figure 11. Serum caffeine (interaction effect, P