Today a study was published finding health benefits to frequent (daily!) consumption of cocoa - improved walking in older persons with peripheral artery disease (PAD). Another reason to drink cocoa and eat dark chocolate!
The study, conducted in Chicago, Illinois, randomly assigned persons, over the age of 60 years with PAD, to different groups. Those who drank a cocoa beverage for 6 months (3 times a day) were able to walk further in a 6 minute walk at the 6 month follow-up (when compared to the placebo/no cocoa group).
The researchers also found that the cocoa significantly improved a number of measures of the calf muscle (e.g. capillary density, calf muscle perfusion), which suggested that there is a durable benefit on the calf muscles from the cocoa beverage. In other words - it's not just a quick sugar-cocoa high that boosted their walking.
On the other hand, the placebo (no cocoa) group deteriorated in how far they could walk over the 6 months, which is consistent with peripheral artery disease. Yes, it typically gets worse over time.
PAD (also called peripheral arterial disease) is a common circulatory problem, due to atherosclerosis, in which there is reduced blood flow to the limbs due to narrowed arteries.Typically the legs don't receive enough blood flow and there is pain when walking (which goes away after resting a bit). Treatments include lifestyle changes (e.g. diet, exercise) and medicines.
What is so beneficial about cocoa? Both regular dark chocolate and cocoa contain flavanols, including epicatechin, which have therapeutic properties and may improve walking in people with PAD. Evidence from other studies of people with and without PAD suggests that cocoa may increase "limb perfusion" and "improve skeletal muscle mitochondrial activity and muscle regeneration".
Can you imagine a prescription for dark chocolate and cocoa on a daily basis? Fantastic! From Medical Xpress: Cocoa could bring sweet relief to walking pain for people with peripheral artery disease
Consumption of cocoa may improve walking performance for patients with peripheral artery disease, according to the results of a small, preliminary, phase II research trial published today in the American Heart Association's journal Circulation Research.
In a small study of 44 peripheral artery disease patients over age 60, 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.
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 discomfort in leg muscles in while walking.
"Few therapies are available for improving walking performance in people with PAD," said lead study author Mary McDermott, M.D., the Jeremiah Stamler professor of medicine and preventive medicine at the Feinberg School of Medicine at Northwestern University in Chicago. "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."
Researchers 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 mgs of epicatechin daily) or a placebo powder packet without cocoa or epicatechin three times daily over six months. Walking performance was measured at the beginning of the study and at six months, with a 6-minute walking measured test twice—2.5 hours after drinking the beverage and at 24 hours after drinking the beverage. Participants were also given a treadmill walking test and had the blood flow to their legs measured using magnetic resonance imaging (MRI). Participants who consented had a calf muscle biopsy to evaluate muscle health.
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. Regular chocolate would not be expected to have the same effect.
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. Researchers 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 declines in their six-minute walk distance over time.
Cocoa appeared to have no effect on treadmill walking performance. However, McDermott said the treadmill walking and the 6-mile walking test are distinct measures of walking endurance and do not respond identically to the same therapy. The improvement in 6-minute distance walking better reflects the type of walking required in daily life, and therefore, these results are a more relevant outcome for patients 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. "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."