Acute effect of cocoa on vascular function in chronic kidney disease patients: a pilot study
University of Delaware
Chronic kidney disease (CKD) is associated with an increased prevalence of cardiovascular disease (CVD) and these individuals often die of CVD before reaching end-stage kidney disease. Dysfunction of the endothelial lining of the blood vessels may cause a worsening of kidney function and increase the CVD risk in this population. Dietary polyphenol consumption, specifically flavonoids, has been associated with reduced CVD risk. Cocoa is a rich source of flavanols, a flavonoid subclass, and has been shown to improve vascular function and prevent CVD in several populations, but not yet in CKD. The aim of this study was to determine the effects of acute cocoa ingestion on endothelial-dependent dilation in subjects with CKD. We hypothesized that brachial artery flow-mediated dilation (FMD), a measure of endothelial function would increase and arterial stiffness and wave reflection would decrease from baseline to two hours following ingestion of 26 g of cocoa (CO) as compared to a placebo (PL). Seven patients with CKD (4M/3F; 53.7 ± 5.1 y) completed the randomized, double-blind, placebo-controlled trial. FMD at baseline (CO 3.96 ± 0.8%, PL 5.05 ± 1.6%) and 2 h post ingestion (CO 5.12 ± 0.9%, PL 7.6 ± 2.8%) was not significantly different between the conditions (p>0.05). Further, the delta change in FMD was not different (CO δ 1.16 ± 0.9 %, PL δ 2.55 ± 1.7%; p>0.05). Arterial stiffness as assessed by carotid-femoral pulse wave velocity did not significantly differ over time (CO δ -0.61 ± 0.7 m/s, PL δ 0.66 ± 0.4 m/s; p>0.05) nor did wave reflection as assessed by augmentation index (CO δ -1.43 ± 2.7, PL δ 1.71 ± 1.5%; p>0.05). In conclusion, our pilot study did not find any significant change in vascular function following ingestion of 26 g of cocoa suggesting that this dose may not be sufficient to rescue vascular dysfunction in this group of patients with CKD.