According to a study conducted by investigators at UC San Diego School of Medicine and VA San Diego Healthcare System (VASDHS), a flavonoid called epicatechin, found in dark chocolate, enhanced mitochondria structure in individuals with advanced heart failure and type 2 diabetes after 3 months. The study is published this week by the journal Clinical and Translational Science. The researchers examined 5 extremely sick patients with major damage to skeletal muscle mitochondria. Mitochondria are structures that provide the energy a cell requires in order to move, divide, and contract. Both heart failure and type 2 diabetes impair these power cells, resulting in abnormalities in skeletal muscle. In individuals with diabetes and heart failure these abnormalities in the heart and skeletal muscle cause decreased functional capacity. Frequently, these patients report difficulty walking even short distances, shortness of breath, as well as lack of energy. Each day for three months, study participants consumed dark chocolate bars and a beverage with a total epicatechin content of around 100 mg. The researchers conducted biopsies of skeletal muscle before and after the 3 month treatment. After treatment, the team examined alterations in mitochondria volume as well as the amount of cristae. Cristae are the internal compartments formed by the inner membrane of a mitochondrion. They are vital for the mitochondria to function efficiently and can be measured by electron microscopy. Francisco J. Villarreal, M.D., Ph.D., of the UC San Diego\'s Department of Medicine\'s Division of Cardiology, and one of the senior researchers of the study, explained: \"The cristae have been severely damaged and decreased in quantity in these patients. After three months, we saw recovery - cristae numbers back toward normal levels, and increases in several molecular indicators involved in new mitochondria production.\" These results are comparable to those from prior studies - demonstrating improvement in skeletal and heart muscle function in animal models after treatment with epicatechin. Due to this, the researchers at UC San Diego School of Medicine and VASDHS will now conduct a larger, placebo-controlled human trial in order to evaluate whether individuals with diabetes and heart failure improve their exercise capacity when receiving treatment with epicatechin-rich cocoa. Pam R. Taub, M.D., an assistant professor of medicine at UC San Diego and the VA San Diego Healthcare System, was the lead researcher of this study and will be leading the new human trial at UC San Diego. The new study will enroll normal sedentary individuals in addition to those with diabetes and heart failure. Participants will receive either epicatechin-rich chocolate treatment or placebo. Other contributors to the study include Israel Ramirez-Sanchez, PhD, Theodore P. Ciaraldi, PhD, Alan S. Maisel, MD, and Robert R. Henry, MD, UC San Diego School of Medicine and VA San Diego Health System; Guy Perkins, PhD, Anne N. Murphy, PhD, Robert Naviaux, MD, PhD and Michael Hogan, PhD, UC San Diego School of Medicine; and Guillermo Ceballos, MD, PhD, Escuela Superior de Medicina del Instituto Politécnico Nacional, Mexico City. The study was supported in part by grants from the National Institutes of Health, American College of Cardiology and The Hershey Company.