A new study published in the journal Food & Function, demonstrated that daily consumption of 9 g of cranberry freeze-dried powder – the equivalent of 100 g of fresh cranberries – for one month improved blood vessel function in healthy men. In addition, researchers identified specific metabolite profiles in plasma that predicted the vascular effects.
"The increases in polyphenols and metabolites in the bloodstream and the related improvements in flow-mediated dilation after cranberry consumption emphasize the important role cranberries may play in cardiovascular disease prevention," explained Dr. Ana Rodriguez-Mateos, senior lecturer at the Department of Nutritional Sciences at King's College London and a co-author on the study.
The study was supported by the Cranberry Institute, the Research Committee of the Medical Faculty of Heinrich-Heine University Dusseldorf and a Susanne Bunnenberg Heart Foundation grant to Dusseldorf Heart Centre.
Beyond the urinary tract
Cranberries are most often associated with urinary tract health, but growing evidence suggests that the benefits of the fruit’s unique and potent polyphenols, known as a-type proanthocyanidins (PACs), extend to the heart.
“There are a number of studies that have looked at the role of cranberry consumption on improving heart health, from increasing good cholesterol levels (HDL) to reducing blood pressure and inflammation,” Amy Howell, PhD, associate research scientist at the Marucci Center for Blueberry Cranberry Research at Rutgers University, told NutraIngredients-USA.
“The results of the current, well-designed study expand the heart-health benefits of daily cranberry consumption by demonstrating positive effects on blood vessel dilation, potentially reducing certain risk factors for stroke and heart attack in the future.”
In the study, the authors noted that to their knowledge this is the first study to investigate improvements in vascular function after daily whole cranberry powder intake in healthy humans.
The power of PACs
To evaluate the effects of daily consumption, the double-blind, parallel-group, randomized controlled trial administered cranberry powder containing 525 mg total polyphenols or a placebo powder without polyphenols to a group of 45 healthy men. Participants were tested after first consumption and after a month of treatment. Flow-mediated dilation (FMD), a sensitive biomarker of cardiovascular disease risk that measures how blood vessels widen when blood flow increases, improved significantly in the cranberry test group.
“These findings are interesting because they demonstrate that even young, healthy men may obtain these heart health benefits after consuming normal serving sizes of cranberry on a daily basis,” Howell said. “The beneficial effects on measures of arterial blood vessel dilation were apparent very quick (after only 2 hours) and continued over the month-long study period.”
The study observed both immediate and chronic benefits but noted a difference in the pattern of metabolites between the two tests.
More benefits to come
The research team recently completed trials investigating how the gut microbiome affects the variability in cardiovascular response to polyphenols. It is currently studying the effects of cranberry consumption on mental health in university students and the role of the gut-brain axis.
Regarding future research, Rodriguez-Mateos said, “It would be very important to further investigate groups including men and women, and young and older individuals, to find more evidence that cranberry polyphenols are effective in maintaining cardiovascular health in the general population.”
Source: Food & Function
March 2022 doi.org/10.1039/D2FO00080F
“Daily consumption of cranberry improves endothelial function in healthy adults: a double blind randomized controlled trial”
Authors: A. Rodriguez-Mateos, et al.