The US Agricultural Research Service (ARS) has launched a database on the web for phytonutrients known as 'proanthocyanidins' - a subclass of flavonoids - in 206 selected foods.
Phytonutrients - the most common being vitamin E, carotenoids, flavonoids, isoflavones and phytosterols - are beneficial compounds found in plant-based foods and are widely studied by the scientific community because of purported health benefits.
Proanthocyanidins are abundant in certain fruits, nuts, beverages (such as red wine and purple grape juice) and even some chocolates. Those in cranberries, for example, may help protect against urinary tract infections. Other health associations of these powerful antioxidants include a reduced risk of cardiovascular diseases, cancer and blood clotting.
Scientists with ARS' Beltsville Human Nutrition Research Center released the food-composition resource this month on the web. Collaborators include scientists at the ARS-funded Arkansas Children's Nutrition Center (ACNC), Mars, and cranberry supplier Ocean Spray Cranberries.
ARS researchers, led by chemist Ronald Prior at ACNC, adapted an earlier method for analysing proanthocyanidins in foods. They used it to analyse them in nationally representative food samples procured by the NDL. "The new compilation is based on acceptable data extracted from reviews of existing scientific literature, as well as data analysed by researchers at ACNC," said the scientists in a statement this week.
Mars said that the ARS study shwoed that the proprietary handling and processing techniques its used to produce some of its cocoa and chocolate products - principally the Dove and CocoaVia bars - were the most effective at promoting heart-healthy chocolate.
Dr Mark A. Kelm, a research chemist with Mars who has been working with the ARS scientists for several years, released more detailed information from the database research which showed that Dove Dark Chocolate Bars, CocoaVia Bars and Cocoapro cocoa powder contain much higher amounts of flavonoids than the averages that appear in the comparable food categories detailed in the USDA-ARS database.
"Mars applauds the tremendous scientific effort and teamwork represented by the release of this USDA-ARS database," said Dr Harold Schmitz, director of science at Mars. "Not only did Mars help develop the methodology to test for these compounds which was then adopted by ARS, but this partnership has helped Mars better understand the value of preserving flavonoids in cocoa and chocolate products."
He added: "This database allows consumers who are interested in heart healthy compounds like flavonoids to more easily find foods that can contribute them to the diet." Which will, of course, do no harm to Mars' profits in today's health-conscious environment.
As if to underline this point, Schmitz stressed that all chocolate was not created equal, suggesting that rival products (including, it should be said, others produced by Mars itself) would not necessarily have the same high flavonoid content.
"We are releasing more data because we want to tell the rest of the story," he said. "Mars has spent nearly 15 years researching cocoa flavonoids to develop the patented and proprietary Cocoapro cocoa process to retain much of the naturally occurring flavonoids in our products. This additional data bears that out."
The new database complements several other databases, including a flavonoids database developed earlier by the NDL, and will impact previous estimates of the total flavonoids in foods. For example, the range of proanthocyanidins (PAC) in various small apples is between 70 and 140 milligrams each, but the sum of other known subclasses of flavonoids in the same samples is only about 5 to 13 mg.
PACs, or condensed tannins, have been identified as the active component responsible for inhibiting the adhesion of certain bacteria to cell walls. This has been postulated as the mechanism behind the cranberry fruits's ability to fight urinary tract infections. These are caused by bacteria in the stool and foods that alter the properties of the foecal bacterial flora may be able to reduce the risk of the disease.