The power of blueberries

Dr. David Nieman, director of the Appalachian State University Human Performance Lab, shows an experimental, polyphenol-rich product at his lab on the North Carolina Research Campus on Wednesday.

KANNAPOLIS, N.C. -- Blueberries have taken center stage again at the North Carolina Research Campus in Kannapolis, this time as part of a discovery researchers say enhances the scientific understanding of nutrient absorption and exercise.

Blueberries have high concentrations of polyphenols, a class of bioactive compounds in fruits and vegetables that help to lower blood pressure and blood glucose, reduce inflammation and fight off the damaging effects of free radicals, according to information provided by the N.C. State University Plants for Human Health Institute.

A new collaborative study involving the N.C. State lab, the Dole Nutrition Research Laboratory, Appalachian State University’s Human Performance Lab and Rutgers University has shown that exercise enhances the absorption of these polyphenols.

The clinical trial was conducted at the Research Campus, and the results were published in PLOS ONE, an open-access, peer-reviewed journal, on Aug. 15.

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 complex for two weeks and during three days of running for two-and-a-half hours each day.

Such intense exercise causes transient inflammation, stress and immune dysfunction, said Dr. David Nieman, director of the Human Performance Lab and lead author on the study. But the study showed the exercise increased permeability in the colon, allowing absorption of a greater amount of polyphenol byproducts.

The study involved the emerging field of metabolomics, a way to measure the unique chemical signatures of specific cellular processes.

“We would not have made this discovery without it,” Nieman said.

That technology allowed scientists to better understand the absorption of polyphenols, which they now believe are absorbed mostly by the colon instead of the small intestine as previously thought.

“Nearly all of the polyphenols … go down to the colon,” Nieman said. “Very little gets through the small intestine.”

His study revealed exercise causes increased gut permeability and greater absorption of polyphenol byproducts

“Exercise helped the polyphenols get right through the colon wall,” Nieman said. “It’s a novel discovery. No one has ever shown that before.”

An equally significant finding was that the runners in the treatment group demonstrated a longer spike in their metabolism after exercise, known as metabolic afterburn.

The treatment group showed increased metabolism for as long as 14 hours after the exercise.

"Burn fat while you sleep is a great message," Dr. Mary Ann Lila, director of the Plants for Human Health Institute, said in a statement. “The findings reinforce the potential benefits of consuming fruits and vegetables, and in particular blueberries, before and after exercise.”

Lila was one of the inventors, in partnership with scientists at Rutgers University, of the technology used to develop nutrient-enhanced food ingredients used in the study.

Earlier this year, Lila and her lab developed kale- and muscadine-infused ingredients for U.S. Army rations utilizing this technology.

Rutgers University is working on developing a product related to the blueberry and green tea substance.

“These kinds of products, they make it easier for mobile people to get the polyphenols,” Nieman said. “I think more and more that’s going to happen in the future. Because carrying around a lot of fresh blueberries and green tea is not easy. It’s just like cellphones and everything else. … I think that’s a product that will kind of fit that context.”

He agreed with Lila that the study adds to a growing body of evidence that blueberries and other fresh produce have a crucial role to play in any successful fitness regime.

People who are thin, exercise regularly and eat lots of fruits and vegetables develop a synergism between exercise and nutrition, he said.

“They have all sorts of reductions in diseases,” he said, including heart disease and colon and breast cancer. “Many of the diseases that plague modern humans are decreased by these polyphenols over a long term.”

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