Reason For Enjoying Dark Hot Chocolate Made Sweeter

In this study, published in the journal Circulation Research, participants with common peripheral artery disease who drank dark hot chocolate three times a day for six months were found to be able to walk significantly further in a walking test; the effect is thought to be due to the epicatechin compounds found in dark chocolate helping to improve blood flow to the participant’s calves that allowed them to walk the extra distance. 

PAD/peripheral artery disease is a narrowing of the arteries which affects one fifth of those over the age of 60 to some degree within the UK causing pain, tightness and cramping of leg muscles while walking. 

“Few therapies are available for improving walking performance in people with PAD,” says study author Professor Mary McDermott, at Northwestern University in Chicago.

“Patients with PAD have difficulty walking that is as bad as people with advanced heart failure. Leg muscles don’t get enough blood supply in PAD leading to injury and in this study, cocoa appeared to be protecting the muscle and improving metabolism. We know that exercise therapy helps people with PAD walk farther, and this early study suggests that cocoa may turn out to be a new way to treat people with PAD,” said Dr Naomi Hamburg, chair of the American Heart Association’s Peripheral Vascular Disease Council.

“We will need larger studies to confirm whether cocoa is an effective treatment for PAD, but maybe, someday, if the research supports it, we may be able to write a prescription for chocolate for our patients with PAD.”

44 participants were involved in this study who were randomly assigned to drink either a placebo or unsweetened cocoa containing 15 grams of cocoa and 75 mgs of epicatechin three times a day for six months. Treadmill testing and walking performance was measured at the beginning of the study and again at six months twice at 2.5 hours and at 24 hours after drinking. Participant blood flow to legs was measured using an MRI scan, and those who consented also had calf muscle biopsy to evaluate muscle health. 

Results showed that those in the cocoa group could walk up to 42.5 metres further in the final six minute walking test compared to the placebo group that suffered a 24.2 metre decline at the end of six months. These findings are consistent with that from other studies in which those with PAD experienced deteriorations in walking distance over time. 

Other improvements found to muscle health included boosts in mitochondrial activity helping cells to convert energy from food, and capillary density factors in delivering oxygen to tissues during exercise. According to the researchers regular chocolate which is often laden with sugar would not be expected to have the same effect as the dark cocoa used in this study. 

 “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 Professor McDermott.