Sweeter Steps: Cocoa May Boost Walking Ability in PAD

Could something that is not a drug, is noninvasive, and tastes delicious actually help patients with PAD walk further and faster? Based on the results of a small pilot project, researchers say they believe flavanol-rich chocolate may have a role in this setting and is worth further study.

“Our main finding was that participants who took a cocoa flavanol drink for 6 months had significant improvement in their 6-minute walk distance compared to those who took a placebo,” Mary M. McDermott, MD (Northwestern University Feinberg School of Medicine, Chicago, IL), told TCTMD. “Also of interest was the fact that MRI measures of blood flow to the legs improved, as did several measures of skeletal muscle function.”

The study builds on minimal data in the literature suggesting that chocolate, specifically dark chocolate, improves walking ability. Most of those studies involved a single dose of chocolate followed by testing to look for immediate effects. McDermott’s study, known as COCOA-PAD, randomized 44 PAD patients to the therapeutic hot cocoa or a similar hot beverage for 6 months and included calf-muscle biopsies.

“In addition to the 6-minute walk test, there were four other measures that significantly improved over time,” McDermott added. “That suggests that this this may be something real.”

In an accompanying editorial, Reiko Matsui, MD, and Naomi M. Hamburg, MD (both from Boston University School of Medicine, MA), say although the findings do not represent conclusive evidence of a link between chocolate consumption and walking performance in those with peripheral disease, they do provide support for moving ahead with a definitive study.

“Additional clinical studies are warranted to evaluate the clinical efficacy of cocoa and other polyphenol-based therapies in patients with PAD,” they write. “Someday, we may be able to prescribe eating more chocolate to our patients with PAD.”

The study was published February 14, 2020, ahead of print in Circulation Research.

Evidence of Durable Benefit

At baseline and 6 months, all participants had a 6-minute walk test at 2.5 hours after consuming their study beverage and again at 24 hours after consuming the beverage. Compared with placebo, the cocoa group improved their walking distance by 42.6 meters at the 2.5-hour mark (P = 0.005) and by 18 meters (P = 0.12) at 24-hour mark.

Muscle biopsies showed improvement in capillary density in the cocoa group, as well as improvement in mitochondrial cytochrome c activity. “Overall the muscle biopsy findings bolster the concept that cocoa may have persistent protective effects in patients with PAD,” Matsui and Hamburg write.

For McDermott, the idea of encouraging therapeutic chocolate intake in PAD patients, while premature, may not be a bad thing.

“There's virtually no adverse effects other than potential for weight gain if people drink a high-caloric cocoa,” she observed. “So, there's really not much downside, and if it might work then why not take it with a caution to attend to the additional calories. We didn't see overall weight gain in either group in our study.”

McDermott also noted that most chocolate is alkalized to improve its taste, so reading labels is important. Although it is possible that the same benefit can be gained from chocolate in a different fashion, such as squares or bars, the nonalkalinized hot cocoa had the combination the researchers were looking for and that’s why it was used in the study.

“Hershey made the product for us, and they tell us that the natural cocoa powder that you can buy is pretty much what we used and it would have the same amount of cocoa and flavanols,” she said. Specifically, people in the study consumed 15 grams of cocoa plus 75 milligrams of epicatechin daily.

McDermott said her group has applied for more grant funding to pursue their chocolate hypothesis further.