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Pilot Randomized Clinical Trial of Cocoa for Peripheral Artery Disease
Study Questions:
Does 6 months of daily cocoa improve walking performance in people with peripheral artery disease (PAD) as compared to placebo?
Methods:
The authors performed a double-blinded randomized clinical trial of patients with documented PAD comparing daily use of cocoa beverage versus placebo. The cocoa beverage contained 15 grams of cocoa and 75 mg of epicatechin. The two primary outcomes were change in 6-minute walk distance measured at 2.5 hours and 24 hours after study beverage consumption (both measured after 6 months of study drug consumption). Outcomes were adjusted for smoking status, race, and body mass index. Calf muscle biopsies were performed to assess mitochondrial cytochrome c oxidase activity, capillary density, calf muscle perfusion, and central nuclei presence.
Results:
The authors randomized 44 patients (mean age 72.3 ± 7.1 years) with mean ankle-brachial index of 0.66 ± 0.15. Most patients (91%) completed the 6-month follow-up. Adjusted 6-minute walk distance at 6 months improved by 42.6 meters (90% confidence interval [CI], +22.2 to + ∞; p = 0.005) at 2.5 hours after final study beverage consumption. Adjusted 6-minute walk distance at 6 months improved by 18.0 meters (90% CI, -1.7 to + ∞; p = 0.12) at 24 hours after final study beverage consumption. Calf muscle biopsy demonstrated improvements in mitochondrial cytochrome c oxidase activity, increased capillary density, improved calf muscle perfusion, and reduced central nuclei, as compared to placebo.
Conclusions:
The authors concluded that preliminary results from this pilot randomized trial suggest a potential therapeutic effect of cocoa on walking performance in patients with PAD.
Perspective:
Cocoa flavanols, including epicatechin, are present in dark chocolate and may increase limb perfusion and skeletal muscle mitochondrial activity/regeneration. This pilot clinical trial suggests potential benefit from daily cocoa consumption as measured by the 6-minute walk distance performed 2.5 hours after study drink consumption. While the 6-minute walk distance measure was not statistically significant when performed 24 hours after drink consumption, the pilot study was likely underpowered to detect such a difference. However, declines in the 6-minute walk at 2.5 hours following placebo drink consumption were greater than expected, and may have influenced the measured benefit when compared to the cocoa-treated group. While the clinical outcome measures were suggestive of a potential benefit, the calf muscle biopsy findings explain a possible mechanism. Before regular dark chocolate consumption can be recommended for patients with PAD, larger confirmatory studies must be performed.
Clinical Topics: Diabetes and Cardiometabolic Disease, Geriatric Cardiology, Prevention, Vascular Medicine, Atherosclerotic Disease (CAD/PAD), Exercise, Smoking
Keywords: Ankle Brachial Index, Beverages, Biopsy, Body Mass Index, Bone Regeneration, Cacao, Catechin, Food, Geriatrics, Muscle, Skeletal, Outcome Assessment, Health Care, Perfusion, Peripheral Arterial Disease, Primary Prevention, Smoking, Vascular Diseases, Walking
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