Featured Research

First Human Trial to Show Metabolic Afterburn, Enhanced Polyphenolic Absorption Following Exercise

August 09, 2013

Scientists at the North Carolina Research Campus (NCRC) in Kannapolis have discovered in a human trial enhanced polyphenolic absorption via the colon into the blood stream. The same human study also found that polyphenolic supplementation in combination with exercise creates a long-lasting spike in polyphenolic metabolism. The study provides clear evidence of an alternate route of bioavailability and a 14-hour afterburn effect from a combination of polyphenols and exercise.


About the Study

The paper, Influence of a Polyphenol-Enriched Protein Powder on Exercise-Induced Inflammation and Oxidative Stress in Athletes: A Randomized Trial Using a Metabolomics Approach1, was published in  PlosOne on August 15, 2013. The lead author is David Nieman, DrPH, FACSM, director of the Appalachian State University (ASU) Human Performance Laboratory and co-authors are Mary Ann Lila, PhD, director of the North Carolina State University Plants for Human Health Institute (PHHI) and Nicholas Gillitt, PhD, director of nutrition research for Dole Food Company.Polyphenols are a class of bioactive compounds in fruits and vegetables that are linked to numerous health benefits such as lowering blood pressure and blood glucose, reducing inflammation and fighting off the damaging effects of free radicals.

“Everybody thinks polyphenols get through by being absorbed in the small intestine, classic bioavailability if you like, but research shows hardly any polyphenols get through that way,” commented Gillitt.  “What we have observed is that they actually make it further down into the colon and get into the system that way. It is an alternative explanation to why these compounds might be in concentrations that could be beneficial to the body.”

The study tested polyphenol supplementation as a countermeasure to inflammation and oxidative stress. Long-distance runners were given either a soy protein complex infused with polyphenols from blueberries and green tea or just the protein complex. The runners ingested the soy protein complex for two weeks and during three days of running for two-and-a-half hours each day.  Each dose was the equivalent of consuming three cups of blueberries and just over a cup of brewed green tea.

Polyphenolic Signature

One finding of the study was that the runners in the treatment group had a polyphenolic signature in their blood that was characteristic of gut microbial metabolism of berry and green tea polyphenols.“Following intensive and prolonged running, athletes experience transient inflammation, oxidative stress and immune dysfunction,” explained Nieman. “Metabolomics, a new technology that simultaneously measures changes in hundreds of metabolites, showed that the majority of the polyphenols went to the colon where the bacteria broke them down into smaller pieces. The intense exercise increased gutpermeability, promoting their transfer into the body in much higher amounts then before the exercise.”

The finding is relevant, Nieman added, because combining polyphenol intake with exercise not only increases gut permeability and allows more polyphenols into the body, the specific polyphenols that were found are known to have anti-oxidant and anti-inflammatory effects.

Metabolic Afterburn

An equally significant finding was that the runners in the treatment group showed a longer spike in their metabolism after exercise. “Burn fat while you sleep is a great message,” emphasized Lila. “We showed that the metabolism is stimulated by exercise, but we saw fatty acid oxidation and ketogenesis with more ketones at 14 hours post exercise in the treatment group. The placebo group went back to normal levels.”

Ketogenesis is the production of biochemicals called ketones from the breakdown of fatty acids in the liver that provide energy to the body, especially the heart and brain.

Nieman views these effects as complementary to a study from 2011 conducted with the UNC Chapel Hill Nutrition Research Institute (NRI), also at the NCRC. Using the NRI’s metabolic chamber, the study showed that the metabolism after 45 minutes of intense exercise stayed elevated in the participants for over 14 hours, accounting for an additional 190 calories above the energy burned directly from the exercise2

Lila is one of the inventors in partnership with scientists at Rutgers University of the soy protein isolate technology used in this study. She has published previous research demonstrating the capacity of the sorption technology to concentrate polyphenols at efficacious levels.3,4 The collaborative study with ASU and Dole proved to be an important step forward in the development of the technology.

“It was the first really strong evidence of bioavailability from this product, which is great because we had a lot of animal models and cell culture but nothing in humans,” Lila said.

The findings reinforce the potential benefits of consuming fruits and vegetables before and after exercise. “It is useful to show in human clinical trials that when you eat fruits and vegetables, these compounds can flood into the system, even if it is not by the classic way everyone thought they did,” Gillitt stressed. “We have already shown the carbohydrates in bananas provide a good source of energy during exercise5. This study shows the polyphenols found in fruits and vegetables could also be helpful to athletes who experience high levels of oxidative stress and inflammation.”

These NC Research Campus scientists are planning additional collaborative studies to build on their findings in order to better understand the physiological mechanisms at play and the potential applications for athletes and consumers.

For more information about this study, contact:

David NiemanNicholas Gillitt  or   Mary Ann Lila

For more information about the NC Research Campus, these research programs and additional scientific discoveries in the areas of human health, nutrition and agriculture, visit the following websites:
ASU Human Performance Laboratory
Dole Food Company
Dole Nutrition Institute
NCSU Plants for Human Health Institute

1 Influence of a Polyphenol-Enriched Protein Powder on Exercise-Induced Inflammation and Oxidative Stress in Athletes: A Randomized Trial Using a Metabolomics ApproachPlosOne, August 15, 2013. David C. Nieman, Appalachian State University (ASU) Human Performance Laboratory at the NC Research Campus, Kannapolis, NC (NCRC); Nicholas D. Gillitt, Dole Nutrition Research Laboratory at the NCRC; Amy M. Knab, ASU Human Performance Laboratory; R. Andrew Shanely, ASU Human Performance Laboratory;  Kirk L. Pappan, Metabolon; Fuxia Jin, Dole Nutrition Research Laboratory; Mary Ann Lila, NC State University Plants for Human Health Institute at the NCRC.

2 A 45-minute vigorous exercise bout increases metabolic rate for 14 hoursMedicine and Science in Sports and Exercise. September 2011. Knab AM, Shanely RA, Corbin KD, Jin f, Sha W, Nieman DC. Human Performance Laboratory, Appalachian State University, North Carolina Research Campus, Kannapolis.

3 Efficient sorption of polyphenols to soybean flour enables natural fortification of foods. Food Chemistry.  April 2012. Diana E. Roopchand, Mary H. Grace, Peter Kuhn, Diana M. Cheng, Nathalie Plundrich, Alexander Poulev, Amy Howell, Bertold Fridlender, Mary Ann Lila, Ilya Raskin. Rutgers, The State University of New Jersey, School of Environmental and Biological Sciences, Foran Hall, 59 Dudley Road, New Brunswick, NJ; Plants for Human Health Institute, North Carolina State University, NC Research Campus; Marucci Center for Blueberry & Cranberry Research, Rutgers University, Chatsworth, NJ.

4 Stable Binding of Alternative Protein-Enriched Food Matrices with Concentrated Cranberry Bioflavonoids for Functional Food ApplicationsJournal of Agricultural and Food Chemistry. Mary H. Grace, Ivette Guzman, Diana E. Roopchand, Kristin Moskal, Diana M. Cheng,Natasha Pogrebnyak, Ilya Raskin, Amy Howell, Mary Ann Lila. Plants for Human; School of Environmental and Biological Sciences, Foran Hall, Rutgers, The State University of New Jersey, New Brunswick, New Jersey; Marucci Center for Blueberry and Cranberry Research, Rutgers University, Chatsworth, New Jersey.

5 Bananas as an Energy Source During Exercise: A Metabolomics ApproachPLoS One. May 2012. Nieman DC, Gillitt ND, Henson DA, Sha W, Shanely RA, Knab AM, Cialdella-Kam L, Jin F.  Appalachian State University Human Performance Lab and Dole Nutrition Research Lab.

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