Cocoa helps prevent heart failure in kidney patients

Nutrients found in cocoa may improve the heart health of patients with advanced kidney disease, and perhaps anyone else at risk for heart disease, according to a new study.

Heart disease is the leading cause of death in patients who have a kidney condition called end-stage renal disease and who require dialysis. There are few effective treatment options to prevent heart failure other than a kidney transplant, according to the American Society of Nephrology.

In the new study, doctors in Germany looked at effects of two nutrients found in cocoa: catechin and epicatechin. These nutrients, thought to be heart-healthy, are part of a group of compounds called flavanols, and are also present in tea, wine and some vegetables.

The doctors concocted a brew with these flavanols and gave it to 26 patients with end-stage renal disease. The drink dramatically improved blood flow and lowered blood pressure in all of the patients within a month, according to the findings, published today (Dec. 17) in the Clinical Journal of the American Society of Nephrology (ASN).

A nearly identical placebo drink, that did not contain the catechin and epicatechin flavanols, had no effect on 26 similar patients in the control group. The study was double blinded, meaning neither the researchers nor the patients knew who had received the placebo drink and who had received the drink with the cocoa nutrients.

However, the researchers noted that although these compounds are found in cocoa beans, they are largely absent from processed chocolate.

The authors of an editorial accompanying the study in the journal wrote that otherwise effective heart medications, such as statins, have failed to improve the heart health of people with end-stage renal disease. "The burden of cardiovascular disease in dialysis patients is so devastating that a promising intervention like cocoa flavanols deserves full attention by the nephrology community," they wrote.

These authors, Drs. Carmine Zoccali and Francesca Mallamaci, both kidney specialists at Italy's National Research Council in Reggio di Calabria, concluded that the new findings, if confirmed by larger studies, may represent a turning point in care for these patients.

Chocolate lovers shouldn't get their hopes up, though. Rassaf told Live Science that the research doesn't imply that chocolate, which is also derived from cocoa, is good for the heart.

"The fresh cacao bean, from the cocoa pod or 'fruit,' is naturally rich in flavanols," Rassaf said. "However, cocoa flavanols are easily destroyed during the processing that occurs to make chocolate and other cocoa products. Therefore, chocolate actually does not typically contain consistent or significant levels of these compounds and should not be viewed as a reliable source of cocoa flavanols."

And, in fact, too much sugar-laden chocolate could lead to Type 2 diabetes, which may then lead to the kidney and heart problems for which cocoa, ironically enough, can help. Maybe that's a bitter bean to swallow.

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