Eight weeks of supplementing the diet with a cranberry juice containing 173 mg of phenolic compounds per serving was associated with significant reductions in C-reactive protein (CRP), diastolic blood pressure, and blood sugar levels, according to findings published in the Journal of Nutrition.
“The magnitude of the significant changes is consistent with the magnitude of changes achieved with other dietary and lifestyle interventions,” wrote the researchers, led by Janet Novotny.
“Lifestyle characteristics, such as consumption of healthful food items, should be encouraged to improve health, reduce incidence of chronic disease and associated morbidities, and ultimately lower health care costs. Consumption of high-polyphenol products such as cranberry juice is a sustainable lifestyle practice that holds notable promise for improving health.”
Cranberry and heart health
While the majority of the science supporting the health benefits of cranberries is for urinary tract health, a growing body of data supports the cardiovascular potential of the berries.
For example, a 2013 study by scientists at the Mayo Clinic and College of Medicine found that two glasses of cranberry juice a day may protect against the development of hardening of the arteries. Writing in the European Journal of Nutrition (Vol. 52, pp 289-296), the Mayo Clinic researchers reported that no effect was observed on the function of the cells lining the arteries (endothelial cells), but cranberry juice may reduce the number of endothelial cells that produce a compound called osteocalcin, which has been linked to hardening of the arteries.
The new study assessed the potential of a low-calorie cranberry juice (sweetened with sucralose) to influence cardiometabolic risk in 56 men and women (mean age of 50, mean weight of 79 kg, and a mean BMI of 28 kg/m2). The participants were assigned to receive either the cranberry juice or a placebo beverage twice per day for eight weeks.
Results of the double-blind, placebo-controlled, parallel-arm study indicated that the cranberry juice lowered fasting serum triglyceride levels, CRP levels (44% lower than placebo), diastolic blood pressure (average of 2.4 mmHg lower), and fasting plasma glucose. The cranberry intervention also experienced improvements in insulin resistance, said the researchers.
“The magnitude of the change in BP observed in this study is consistent with that obtained with recommended dietary patterns to reduce BP, such as the Dietary Approaches to Stop Hypertension Trial diet or with a low-sodium diet,” said the researchers. “The magnitude of the change observed in the current study could be associated with a 15% decrease in risk of stroke and a 10% decrease in risk of coronary heart disease.”
“Because fresh cranberries are not typically consumed raw because of their tart and astringent taste and because cranberries are consumed almost entirely as juice in the US diet, our study used juice. It is unknown whether the benefits observed here would translate to whole fruit, which would provide fiber in addition to the polyphenols.”
'Achieved with reasonable serving sizes'
Commenting independently on the research, Amy Howell, PhD, Associate Research Scientist at the Marucci Center for Blueberry Cranberry Research, Rutgers University, told NutraIngredients-USA: "This well-designed study with a sufficiently long intervention period of 8 weeks, twice-daily dosing and a tightly controlled diet clearly showed that cardiovascular risk factors can be reduced following consumption of low-calorie cranberry juice on a daily basis.
"Cranberry contains a broad-array of polyphenolic compounds that appear to have effects that reach will beyond maintenance of urinary tract health. The multiple health benefits of cranberry juice that are achieved with reasonable serving sizes should encourage its use in the daily diet."
Source: Journal of Nutrition
Published online ahead of print, doi: 10.3945/jn.114.203190
“Cranberry Juice Consumption Lowers Markers of Cardiometabolic Risk, Including Blood Pressure and Circulating C-Reactive Protein, Triglyceride, and Glucose Concentrations in Adults”
Authors: J.A. Novotny, D.J. Baer, C. Khoo, S.K Gebauer, C.S. Charron