Effects of dark chocolate and cocoa consumption on endothelial function and arterial stiffness in overweight adults

Abstract

The consumption of cocoa and dark chocolate is associated with a lower risk of CVD, and improvements in endothelial function may mediate this relationship. Less is known about the effects of cocoa/chocolate on the augmentation index (AI), a measure of vascular stiffness and vascular tone in the peripheral arterioles. We enrolled thirty middle-aged, overweight adults in a randomised, placebo-controlled, 4-week, cross-over study. During the active treatment (cocoa) period, the participants consumed 37 g/d of dark chocolate and a sugarfree cocoa beverage (total cocoa ¼ 22 g/d, total flavanols (TF) ¼ 814 mg/d). Colour-matched controls included a low-flavanol chocolate bar and a cocoa-free beverage with no added sugar (TF ¼ 3 mg/d). Treatments were matched for total fat, saturated fat, carbohydrates and protein. The cocoa treatment significantly increased the basal diameter and peak diameter of the brachial artery by 6 % (þ2 mm) and basal blood flow volume by 22 %. Substantial decreases in the AI, a measure of arterial stiffness, were observed in only women. Flow-mediated dilation and the reactive hyperaemia index remained unchanged. The consumption of cocoa had no effect on fasting blood measures, while the control treatment increased fasting insulin concentration and insulin resistance (P¼0·01). Fasting blood pressure (BP) remained unchanged, although the acute consumption of cocoa increased resting BP by 4 mmHg. In summary, the high-flavanol cocoa and dark chocolate treatment was associated with enhanced vasodilation in both conduit and resistance arteries and was accompanied by significant reductions in arterial stiffness in women.

The Impact of Repetitive Long-duration Water Immersion on Vascular Function

“…Previous studies have documented changes in arterial stiffness following both acute and chronic interventions, and acute changes have been detected in response to many stimuli other than diving or immersion [57,58,59,60,61]. Acute aerobic exercise (rowing) caused stiffness to decrease [62], and acute sprint interval exercise caused increased compliance but no change in brachial artery stiffness [63].…”

Relation of Habitual Chocolate Consumption to Arterial Stiffness in a Community-Based Sample: Preliminary Findings

“…In a randomized, cross-over study, Vlachopoulous et al [23] examined the immediate effects of the consumption of 100 g of dark chocolate in 17 young healthy adults and found no significant change in PWV, despite increased flow-mediated dilation. In contrast, West et al [24] examined the effect of daily cocoa and dark chocolate consumption (22 g/day of natural cocoa) for 4 weeks on endothelial function and arterial stiffness in 30 overweight adults in a placebo-controlled, randomized, crossover study. Significant reductions in peripheral arterial stiffness were observed in women only.…”

“…Observational cross-sectional findings with regard to cocoa/chocolate intakes and arterial stiffness have been inconsistent to date [20,21]. Similarly, a few randomized trials examining the short-term effects on arterial stiffness from chocolate/cocoa consumption ranging from a single dose to daily consumption over a number of weeks have shown mixed results [22,23,24,25]. We have not identified any cohort studies that have examined associations between longer-term habitual chocolate intake over a period of years and measures of arterial stiffness.…”

Cocoa, Blood Pressure, and Vascular Function

“…Moreover, the positive effect of cocoa consumption on endothelial function was not associated with weight gain (48). Conversely, in a subsequent study, an increase in basal and peak brachial artery diameter, with no consequent change in FMD, was assessed in a group of 30 overweight patients after 30 days high-flavanol chocolate intake (71). In a diabetic population, high-flavanol cocoa consumption was associated with statistically significant improvement in vascular function both acutely (after 2 h) and chronically (30 days) in two different studies (72,73).…”