Effects of cranberry juice consumption on vascular function in patients with coronary artery disease.

ABSTRACTBackground: Cranberry juice contains polyphenolic compoundsthat could improve endothelial function and reduce cardiovasculardisease risk.Objective: The objective was to examine the effects of cranberryjuice on vascular function in subjects with coronary artery disease.Design: We completed an acute pilot study with no placebo (n = 15)and a chronic placebo-controlled crossover study (n = 44) thatexamined the effects of cranberry juice on vascular function insubjects with coronary artery disease.Results: In the chronic crossover study, subjects with coronaryheart disease consumed a research preparation of double-strengthcranberry juice (54% juice, 835 mg total polyphenols, and 94 mganthocyanins) or a matched placebo beverage (480 mL/d) for 4 wkeach with a 2-wk rest period between beverages. Beverage orderwas randomized, and participants refrained from consuming otherﬂavonoid-containing beverages during the study. Vascular functionwas measured before and after each beverage, with the follow-uptesting 12 h after consumption of the last beverage. Mean (6SD)carotid-femoral pulse wave velocity, a measure of central aorticstiffness, decreased after cranberry juice (8.3 6 2.3 to 7.8 6 2.2m/s) in contrast with an increase (8.0 6 2.0 to 8.4 6 2.8 m/s) afterplacebo (P = 0.003). Brachial artery ﬂow-mediated dilation, digitalpulse amplitude tonometry, blood pressure, and carotid-radial pulsewave velocity did not change. In the uncontrolled pilot study, weobserved improved brachial artery ﬂow-mediated dilation (7.7 62.9% to 8.7 6 3.1%, P = 0.01) and digital pulse amplitude tonom-etry ratio (0.10 6 0.12 to 0.23 6 0.16, P = 0.001) 4 h after con-sumption of a single 480-mL portion of cranberry juice.Conclusions: Chronic cranberry juice consumption reduced carotidfemoral pulse wave velocity—a clinically relevant measure of arte-rial stiffness. The uncontrolled pilot study suggested an acute beneﬁt;however, no chronic effect on measures of endothelial vasodilatorfunction was found. This trial was registered at clinicaltrials.gov asNCT00553904. Am J Clin Nutr doi: 10.3945/ajcn.110.004242.INTRODUCTIONEpidemiologic studies have shown that consumption of ﬂa-vonoid-containing foods and beverages is associated with re-duced cardiovascular disease risk (1, 2). Whereas the mechanismsaccounting for this beneﬁt remain incompletely deﬁned, clinicalstudies have identiﬁed many relevant effects. For example,consumption of grapes, cocoa, and other ﬂavonoid-containingfoods may reduce blood pressure (3), platelet aggregation (4),insulin resistance (5), and cholesterol concentrations (6). Invitroand biomarker studies suggestthat such foods have antiin-ﬂammatory effects (2, 7). Recently, there has been particularinterest in the possibility that ﬂavonoids also reduce cardiovas-cular disease risk by reversing endothelial dysfunction.Endothelial dysfunction is a key mechanism in the patho-genesis of atherosclerotic vascular disease (8, 9). Risk factorsdecrease the bioavailability of endothelium-derived nitric oxideand induce a proinﬂammatory endothelial phenotype that pro-motes atherosclerosis and arterial stiffness. Risk-reduction ther-apies and lifestyle changes improve endothelial function (9).Prior studies have shown favorable effects of tea, cocoa, grapejuice, and other dietary sources of ﬂavonoids on endothelialfunction in patients with coronary disease and other risk factors(10–12).Cranberry juice is a rich source of polyphenolic compounds,particularly anthocyanins (13, 14). Investigators have proposedthat cranberry consumption might have protective effects againstcardiovascular disease by reducing inﬂammation and serumlipids (15, 16). The present study was designed to investigatewhether consumption of cranberry juice would improve vascularfunctionandreduceinﬂammation.Weusednoninvasivemethodsto examine the effects of cranberry juice on multiple measuresof vascular function in different vascular beds, including endo-thelium-dependent vasodilation and arterial stiffness in patientswith coronary artery disease.