In a new study, researchers found that consumption of cocoa may improve walking performance for patients with peripheral artery disease.
In the study of 44 peripheral artery disease patients over age 60, the team found those who drank a beverage containing flavanol-rich cocoa three times a day for six months were able to walk up to 42.6 meters further in a 6-minute walking test, compared to those who drank the same number and type of beverages without cocoa.
Those who drank the flavanol-rich cocoa also had improved blood flow to their calves and some improved muscle function compared to the placebo group.
The research was conducted by a team at Northwestern University.
Peripheral artery disease or PAD, a narrowing of the arteries that reduces blood flow from the heart to the legs, affects over 8.5 million people 40 years of age and older nationwide.
The most common symptoms are pain, tightness, cramping, weakness, or other discomforts in leg muscles in while walking.
Few therapies are available for improving walking performance in people with PAD.
In addition to reduced blood flow to the legs, people with peripheral artery disease have been shown to have damaged mitochondria in their calf muscles, perhaps caused by the reduced blood flow.
Mitochondria are known as the powerhouse of the cell, converting food to energy.
Previous research has shown that better mitochondrial health and activity are associated with better walking performance and improving the health of damaged mitochondria could lead to walking improvements.
In the study, the team hypothesized that epicatechin, a major flavanol component of cocoa, may increase mitochondrial activity and muscle health in the calves of patients with lower extremity peripheral artery disease, potentially improving patient walking ability.
Epicatechins and flavanols also have the potential to improve blood flow.
Study participants were randomly assigned to drink milk or water mixed with the contents of a powder packet containing flavanol-rich cocoa (15 grams of cocoa and 75 mg of epicatechin daily) or a placebo powder packet without cocoa or epicatechin three times daily over six months.
The cocoa used in the study is commonly available natural unsweetened cocoa powder., which is rich in the flavanol epicatechin, found in larger quantities in dark chocolate (>85% cacao) than in milk chocolate.
The researchers found that the patients who consumed cocoa showed significant improvement — walking an average of almost 43 meters further in the 6-minute walking test compared to their baseline results during the test performed at 2.5 hours after the final study beverage.
They also found increased mitochondrial activity, increased capillary density, and other improvements to muscle health in those who consumed the cocoa.
Patients who drank the placebo beverage had a decline of 24.2 meters in their walking distance at 2.5 hours after the final study beverage compared to their baseline results.
This is consistent with other studies, in which people with PAD without treatment have declined in their six-minute walk distance over time.
The team says cocoa treatment was also linked to increased capillary density, limb perfusion, mitochondrial activity, and an additional measure of overall skeletal muscle health.
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.
One author of the study is Mary McDermott, M.D., the Jeremiah Stamler professor of medicine and preventive medicine.
The study is published in Circulation Research.
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