Drinking a polyphenol-rich juice every day for four weeks was associated with a change in the expression of a range of proteins linked to coronary artery disease towards a “healthy state”, report researchers from the University of Glasgow, Mosaiques diagnostics GmbH (Germany), and Coca-Cola.
Using a technique called proteomics, the researchers report a four-fold or more difference in the levels of 27 polypeptides between people consuming the polyphenol-rich juice and a placebo. Seven of these polypeptides have been reported to be markers of coronary artery disease (CAD).
“Our data suggest that the polyphenol rich drink may have beneficial effects on urinary biomarkers of CAD,” wrote the researchers in the Journal of Agricultural and Food Chemistry.
“The data encourage the planning of future prospective studies, aimed at investigating significant effects of polyphenol rich dietary products.”
Rising to the challenge
Polyphenols are receiving extensive research due to their potent antioxidant activity, their ability to mop-up harmful free radicals, and the associated health benefits. Many have also been implicated in possible protection against diseases such as cancer and cardiovascular disease, while some have been reported to potentially offer protection from Alzheimer's.
Despite this interest, Ming Hu from the University of Houston recently issued "a call to arms" for more relevant research into the bioavailability and utilisation of the antioxidants, particularly polyphenols, in order to help "the successful development of polyphenols as chemopreventive agents in the future" (Molecular Pharmaceutics, Vol. 4, pp. 805-806).
The new study builds on early research by the same scientists, published last year in Molecular Nutrition & Food Research (doi: 10.1002/mnfr.200900611), which verified that polyphenols are absorbed into the blood stream when consumed from a beverage.
Study details
The new study involved 39 middle aged overweight people and randomly assigned them to receive either 500 mL per day of polyphenol-rich juice or placebo for four weeks.
The juice contained green tea flavan-3-ols, citrus flavanones, grape seed and pomace procyanidins, procyanidins and chlorogenic acid, apple dihydrochalcones, and grape anthocyanins.
The juice contained 1,052 micromoles of phenolic and polyphenolic compounds and 157 mg of procyanidins per 500 mL.
Results showed that, of the 93 polypeptides identified as marker candidates, 27 polypeptides had levels that were at least four-fold different between the placebo and juice groups.
Expression of seven of these – previously linked to CAD – moved in a direction that was “closer to the healthy state” in people in the polyphenol group, said the researchers, while people in the placebo group showed a movement “closer to CAD state”.
Caution
While the results are encouraging, the researchers note that this is only a pilot study and that properly controlled studies to evaluate the potential effects of polyphenols on cardiovascular disease are needed in the future.
“If such effects could be substantiated, then the results would further advance the notion that specific food supplements may indeed possess some beneficial effects on the development of cardiovascular pathology.”
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, Articles ASAP (As Soon As Publishable), doi: 10.1021/jf203369r
Authors: W. Mullen, J. Gonzalez, J. Siwy, J. Franke, N. Sattar, A. Mullan, S. Roberts, C. Delles, H. Mischak, A. Albalat