Written by Chrystal Moulton, Staff Writer. Polyphenol rich blueberries and green tea supplementation reduced the exercise induced inflammation and oxidative stress that occurred during intense exercise in this study of 35 long distance runners.
Polyphenolic compounds are generally praised for their ability to combat free radicals caused by oxidative stress and inflammation. In the world of nutrition, certain foods are especially encouraged because of their polyphenolic content. This includes but is not limited to blueberries, acai, green tea, and even red wine. (1)
In this study, researchers wanted to test the effects of a blueberry green tea soy protein compound on the effects of intense exercise. They hypothesized that this particular mix of high polyphenolic foods would be effective in combating the inflammation and oxidative stress induced by intense exercise.
In order to test whether the antioxidant mixture could ameliorate inflammation and stress caused by exercise, researchers designed the study in a double-blind placebo controlled protocol. Their test sample included 38 long distance runners aged 19-45 years old. All of the 38 runners underwent a baseline test to determine eligibility for the study. Researchers tested for their maximum oxygen use (VO2max) during a graded treadmill test. Of them 35 who passed the baseline examination were randomized into two groups: placebo, who received a soy protein isolate with non-polyphenolic colorings and experimental group, who received a 3:1 blueberry green tea polyphenol soy protein complex. Over the 17 day period of the study, participants were given 20 grams (one tablespoon) of either the placebo mixture or treatment dissolved in 237 ml of water in the morning and at lunch time. For 14 days of the test period, athletes underwent normal training routines. During the last 3 days of the study, training exercise was intensified. For the 3 day period, in the morning, subjects consumed the normal supplement amount with breakfast. At noon, they were given the nutritional drink, Boost Plus. Blood was drawn at 2:30pm from all participants and supplement was given once again. At 3pm, volunteers ran on treadmills for 2.5 hr at 70%VO2 max. Water was provided throughout the exercise drill. After 1 hour of exercise, subjects were supplemented once more and oxygen consumption and ventilation was measured. Also every 30 minutes, each subject’s heart rate and distance ran were recorded. They were also asked about their level of tiredness during the workout. This schedule was repeated for the next two days without the 2:30pm blood draw. On the third day after completion of intense exercise and in the following morning, 14 hours later, blood was taken. After the test period, subjects were given a symptom log to determine overall well-being.
Researchers used blood samples taken from volunteers during the study to determine plasma concentration of six inflammatory cytokines, serum chemistry, complete blood count, and protein carbonyl concentration.
In the end, participants were 100% compliant to the study protocol. Supplementation of 40 g/d of the green tea polyphenol soy protein complex provided 2,136 mg gallic acid equivalents and 1,001 mg of green tea flavan-3-ols, antioxidant species found in blueberries and green tea. There was no significant difference in weight, oxygen consumption, heart rate, and rate of perceived exertion during the 3 day period of intense exercise between treatment and placebo groups. Inflammatory markers were not significantly different from the treatment to the placebo. In both groups, there was a significant increase in oxidative stress and inflammation. The polyphenol soy protein complex did not reduce biomarkers of oxidative stress and inflammation produced as a result of the 3-day intense exercise. However, post-exercise values show a 1.75 fold increase in hydroxybutyrate and a 1.60 fold increase in acetoacetate (p<0.01) 14 hours after the completion of the intense exercise regimen. Changes in these metabolites indicate an exercise induced significant increase in gut permeability, fatty acid oxidation, and ketone synthesis in the treatment group versus placebo (p<0.01).
Source: Nieman, David C., Nicholas D. Gillitt, Amy M. Knab, R. Andrew Shanely, Kirk L. Pappan, Fuxia Jin, and Mary Ann Lila. “Influence of a polyphenol-enriched protein powder on exercise-induced inflammation and oxidative stress in athletes: a randomized trial using a metabolomics approach.” PLoS One 8, no. 8 (2013): e72215.
© 2013 Nieman et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Posted October 22, 2014.
Chrystal Moulton BA, PMP, is a 2008 graduate of the University of Illinois at Chicago. She graduated with a bachelor’s in psychology with a focus on premedical studies and is a licensed project manager. She currently resides in Indianapolis, IN.
References:
- Polyphenols: food sources and bioavailability. Manach C, Scalbert A, Morand C, et al. Am J Clin Nutr May 2004 vol. 79 no. 5 727-747.
- Influence of a polyphenol-enriched protein powder on exercise-induced inflammation and oxidative stress in athletes: a randomized trial using a metabolomics approach. NiemanDC, GillittND, Knab AM, et al. PLoS One. 2013 Aug 15; 8(8):e72215. doi: 10.1371/journal.pone.0072215.
