A new study reveals for the first time that a unique class of cranberry polyphenols, Type-A proanthocyanidins (PACs), are found in human urine after consumption of a cranberry beverage. The study, led by Jeffrey Blumberg, PhD, at Tufts University (Boston, MA) and supported by the Ocean Spray Cranberries, Inc, offers a breakthrough insight into the bioavailability and metabolism of cranberry bioactives.
In test tube studies, Type-A PACs have been shown to prevent bacteria from adhering to cells, a mechanism that may underlie the association between cranberry consumption and reduced risk of certain types of infection. This is consistent with clinical studies that have found a decrease in urinary tract infections after drinking cranberry juice. The positive results of the current discovery open up the possibility of using cranberry PACs as a biomarker of compliance for future clinical trials.
The study participants, healthy men and postmenopausal women aged 50-70 years, consumed a low polyphenol diet for three days followed by a serving of a cranberry beverage equivalent to two servings of Ocean Spray Cranberry Juice Cocktail. Collected at set intervals, urine samples were assessed for flavanols, phenolic acids, anthocyanins and Type-A PACs. Along with the presence of the first three classes of compounds, the results also revealed a measurable concentration of PAC phenolic compounds in the participants’ urine samples. The Tufts’ study suggests that different phenolic constituents found in cranberry juice are absorbed and metabolized at different locations along the gastrointestinal tract in healthy adults.
Jeffrey Blumberg, PhD, professor of nutrition science and policy and director of the Antioxidants Research Laboratory at Tufts University commented: “In the past, many observational studies have attributed various health benefits to the North American cranberry, including protection against urinary tract infections and stomach ulcers as well as promotion of cardiovascular health. This new evidence provides another step toward supporting the findings of past in vitro studies investigating the anti-adhesion mechanism of cranberry PACs, demonstrating how the high polyphenol content of cranberry juice may help maintain urinary tract health.”
Christina Khoo, PhD, senior manager, Ocean Spray, added: “We are very excited about the results of this study that confirms cranberry’s significant levels of Type-A PAC content. Our support of this research underpins Ocean Spray’s commitment to advancing the science of cranberries. Following our recent strategic partnership with Artemis International, a specialty provider of nutraceutical ingredients, we will continue to deliver high quality, innovative ingredients to the nutraceutical marketplace worldwide.”