Cocoa and Flavanols Make Walking Easier for PAD Patients

Mary McDermott, MD

Results of a phase 2 clinical trial suggest increased consumption of cocoa might have therapeutic effects and allow patients with peripheral artery disease (PAD) to walk easier.

The study found increased intake of cocoa and epicatechin—a major flavanol component of cocoa—was tied to significant improvements in six-minute walking distance as well as increasing capillary density and muscle perfusion in patients with PAD when compared with placebo.

“If our results are confirmed in a larger trial, these findings suggest that cocoa, a relatively inexpensive, safe and accessible product, could potentially produce significant improvements in calf muscle health, blood flow, and walking performance for PAD patients,” said lead investigator Mary McDermott, MD, professor of medicine and preventive medicine at Feinberg School of Medicine at Northwestern University in Chicago, in a statement.

With no effective therapeutic options available to patients with PAD, McDermott and a team of colleagues designed the COCOA-PAD to assess whether the impact of cocoa flavanols could improve walling performance in people with PAD. Investigators noted previous research linked consumption of dark chocolate to increased walking distance, but no studies had examined the impact of cocoa on walking ability in people with PAD.

The study was designed as a double-blind, randomized, pilot study to assess the impact of consuming a cocoa beverage on the six-minute walking distance at 6 months compared to placebo. Participants were randomized to receive either a powder packet containing a mixture of cocoa and epicatechin or a placebo powder packet 3 times daily for 6 months. Investigators noted participants in the intervention group received 15 grams of cocoa and 75 mg of epicatechin daily and the powder packets given to participants were manufactured by The Hershey Company.

The primary outcomes in the trial were change in six-minute walk distance measured 2.5 hours and 24 hours after consumption of a study beverage at six-month follow-up. To be included COCOA-PAD participants were required to be at least 60 years of age and have the presence of PAD, which was defined as an ankle brachial index of 0.90 or greater in either leg or vascular laboratory of angiographic evidence of PAD.

A total of 118 participants consented to partake in the study, of which 44 were randomized—23 to intervention and 21 to placebo. Of the 44 participants included, 40 completed at least 1 of the six-month follow-up measures. Investigators pointed out analyses were adjusted for baseline differences including BMI, smoking status, and race.

Results of the intention to treat analyses revealed participants in the intervention group improved six-minute walk distance at six months by 42.6 meters at 2.5 hours (CI, +22.2 to +∞; P = .005) and by 18 meters at the 24 hours (90% CI, -1.7 to +∞, P = .12) compared to participants in the placebo group.

Calf muscle biopsies, which involved the removal of 250 mg of muscle, were successfully performed in 21 participants and revealed more about the potential impact of cocoa consumption. Results of these biopsies indicated participants receiving the cocoa intervention experienced improved mitochondrial cytochrome c oxidase activity (P = .013), increased capillary density (P = .014), improved calf muscle perfusion (P = .098), and reduced central nuclei (P = .024) compared to participants receiving placebo.

Multiple limitations were noted by investigators. Limitations included small sample size, imbalance of BMI, sex, and race as a result of randomization, and the presence of multiple study outcomes means some findings could be due to chance. McDermott and colleagues assert the results of the study warrant further investigation into the potential impact of cocoa on walking performance in people with PAD.

“While we expected the improvements in walking, we were particularly pleased to see that cocoa treatment was also associated with increased capillary density, limb perfusion, mitochondrial activity, and an additional measure of overall skeletal muscle health,” McDermott said, in the aforementioned statement.

This study, “Cocoa to Improve Walking Performance in Older People With Peripheral Artery Disease: The Cocoa-Pad Pilot Randomized Clinical Trial,” was published online in Circulation Research.