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Chocolate Sweetens Life for Heart Failure Patients

Cocoa and chocolate for heart failure patients

For a small group of patients with heart failure and type 2 diabetes, a daily dose of chocolate did more than taste good—it sweetened their life and improved their muscle function. The success seen in this study has prompted plans for another larger trial in patients with heart failure and type 2 diabetes.

Chocolate could be what the doctor ordered

For many people, chocolate is nothing more than a sweet treat and a quick pick-me-up snack. But for others, chocolate is like a prescription for health.

Among the numerous health-related benefits that have been credited or attributed to chocolate (see below), investigators at University of California San Diego (UCSD) School of Medicine and VA San Diego HealthCare System (VASDHS) might add one concerning its positive impact on skeletal muscle function.

The study involved five extremely ill individuals who had advanced heart failure and type 2 diabetes, conditions associated with damage to mitochondria. The mitochondria are organelles that produce energy. which cells need to survive and reproduce.

Damaged mitochondria in patients with heart failure and type 2 diabetes causes abnormalities in skeletal muscle, which in turn leads to shortness of breath, fatigue, and difficulty walking short distances.

In the study, the participants ate dark chocolate bars and drank a beverage containing epicatechin, for a total epicatechin content of about 100 mg daily. The study lasted for three months.

Epicatechin is a polyphenol and flavanol found in cocoa, green tea, berries, and red wine. According to the US Department of Agriculture, dark chocolate provides between 52 and 125 mg of epicatechin per 100 grams of chocolate.

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The investigators conducted biopsies of skeletal muscle both before and after the three-month study. At three months, the skeletal muscle samples showed improvements in both mitochondria volume and in the amount of cristae, which are essential for efficient functioning of mitochondria.

According to one of the study’s senior researchers, Francisco J. Villarreal, MD, PhD, in UCSD’s Department of Medicine, “After three months, we saw recovery—cristae numbers back toward normal levels,” whereas the cristae had declined in number earlier. The investigators also observed “increases in several molecular indicators involved in new mitochondria production.”

Heart failure is a condition in which the heart is unable to pump enough blood throughout the body, which results in shortness of breath, fatigue, accumulation of fluid in the lower extremities, and blood and fluid in the lungs. Approximately 5 million people in the United States have heart failure, whose leading causes include coronary artery disease, diabetes, and high blood pressure.

Other health benefits of chocolate
Chocolate and its various polyphenols have demonstrated promising health benefits in other studies as well. In a University of Cambridge meta-analysis involving more than 100,000 people, for example, the researchers evaluated the effect of chocolate on coronary heart disease, incidence of stroke, diabetes, incidence of cardiovascular disease and mortality, and deaths from stroke.

They concluded that the “highest levels of chocolate consumption were associated with a 37% reduction in cardiovascular disease and a 29% reduction in stroke compared with lowest levels.”

A University of Reading study found that consuming dark chocolate had a positive impact on blood vessel function. In a comparison of dark chocolate versus white chocolate, researchers found that healthy adults who consumed the former showed improvement in cognitive function and visual sensitivity.

Results of this latest study from UCSD add to the growing volume of literature regarding the health benefits of chocolate. They have also prompted researchers to launch a larger, placebo-controlled trial involving patients with both heart failure and type 2 diabetes as well as healthy sedentary individuals to determine if chocolate will sweeten their lives—and improve their exercise capacity.

Buitrago-Lopez A et al. Chocolate consumption and cardiometabolic disorders: systematic review and meta-analysis. BMJ 2011; 343:d4488
Field DT et al. Consumption of cocoa flavanols results in an acute improvement in visual and cognitive functions. Physiology & Behavior 2011 Jun 1; 103(3-4): 255-60
Gu L et al. Procyanidin and catechins contents and antioxidant capacity of cocoa and chocolate products. J Agric Food Chem 2006; 54:4057-61
Taub PR, Ramirez-Sanchez I et al. Alterations in skeletal muscle indicators of mitochondrial structure and biogenesis in patients with type 2 diabetes and heart failure: effects of epicatechin rich cocoa. Clinical and Translational Science 2012 Feb; 5(1): 43-47

Image: Courtesy Wikimedia Commons



Unfortunately, commercial processing destroys most of the flavonoids (epicatechins). So the chocolate used in these studies is not available to the consumer when they go to their local store. The only way you know you are getting the flavonoids is to eat a dark chocolate that has certified the amount of flavonoids on their finished product. There is a great article on the difference between "good" chocolate and "bad" chocolate at cocoa101.com.