New cocoa evidence on why plant foods are beneficial to cardiovascular health
Researchers identify a compound in cocoa responsible for improving blood flow
While a growing number of studies has shown a link between flavanol-rich cocoa and cardiovascular health, scientists have now substantiated a causal relationship between specific compounds present in cocoa and cardiovascular health. Published today in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) , this new study identifies the flavanol, (-)epicatechin, as one of the bioactive nutrients in cocoa that can improve the ability of blood vessels to relax.
An international team of scientists from the University of Dusseldorf, Germany; the University of California, Davis; Mars, Incorporated; and Harvard Medical School conducted a series of studies examining the role of specific cocoa flavanols in cardiovascular health.
"Applying accepted causality criteria and gold standard methodologies, we have been able to advance our understanding of the relationship between the intake of certain flavanols present in cocoa, their absorption into the circulation, and their effects on cardiovascular function," said lead author Hagen Schroeter, PhD, faculty member at the University of California, Davis. "This study established direct evidence for the effect of the flavanol(-)epicatechin as a mediator of blood vessel relaxation."
In a randomized, double-blind, cross-over investigation, the researchers provided healthy male participants with a specially prepared cocoa drink that was either high or low in certain cocoa flavanols. Only the group consuming the flavanol-rich cocoa experienced increased blood vessel relaxation. The researchers demonstrated that the relaxation response mediated by cocoa flavanols is dependent on nitric oxide, a key signal released by the inner lining of blood vessels (the endothelium) essential for normal blood vessel function and healthy blood flow.
To provide direct evidence for the specific flavanol in cocoa that is partly responsible for the circulatory benefits, the research team conducted a "proof-of-concept" study. During this part of the investigation, participants drank either a placebo or a beverage containing isolated, cocoa-derived (-)epicatechin. The researchers demonstrated that the group of participants receiving the (-)epicatechin had vessel relaxation and nitric oxide responses similar to those experienced following the consumption of the flavanol-rich cocoa drink. Based on these findings, the investigators concluded that (-)epicatechin is one of the active nutrients in certain cocoas exerting the observed vascular benefits.
"Pinpointing specific nutrients responsible for the observed cardiovascular effects, as we are seeing here with (-)epicatechin, opens up new possibilities for the development of dietary or therapeutic interventions for cardiovascular disease," said co-author Norman Hollenberg, MD, PhD, professor of medicine at Harvard Medical School.
(-)Epicatechin, a nutrient that may be found in certain fruit and vegetables, green teas, red wine and purple grape juice, is especially abundant in certain cocoas. "This new insight into the bioactivity of flavanol nutrients is an important piece of information that will help us understand why diets rich in fruits and vegetables promote cardiovascular health," said co-author Carl L. Keen, PhD, professor of nutrition and internal medicine at the University of California, Davis.
To assess the potential long-term benefits of a flavanol-rich diet, the researchers studied two populations of Kuna Indians of Panama. Previous work by Dr. Norman Hollenberg has shown that hypertension is rare among the indigenous Kuna Indians living on the islands as compared to those living on the mainland. The island-dwelling Kuna Indians traditionally consume large quantities of flavanol-rich cocoa (an average of 3-4 cups daily), while those who live in the suburbs of Panama City consume very little cocoa, supporting the idea that cocoa flavanols may be responsible for the lower blood pressure in the island dwellers. Linking Dr. Hollenbergs observations to their own findings, Schroeter and colleagues found that the Kuna Indians on the island who regularly consume flavanol-rich cocoa had higher levels of flavanols, as well as higher levels of nitric oxide metabolites in their circulation compared to the mainland Indians who consume little cocoa. "These findings suggest that frequent intake of cocoa flavanols can have biological effects with important implications for long-term cardiovascular health," said Dr. Hollenberg.
In addition to collaborating on this research, Mars, Incorporated financially supported it and provided the flavanol-rich cocoa (Cocoapro® cocoa powder) that was used throughout these ivestigations. "After more than 15 years of commitment to cocoa science research, we are excited to see such great progress in uncovering the link between cocoa flavanols and heart health," said Harold Schmitz, PhD, chief science officer of Mars, Incorporated and co-author of the study. "Traditional cocoa processing often destroys the flavanols, but Mars technology helps to retain these naturally occurring nutrients from cocoa. This new research emphasizes the importance of understanding the potential public health applications of emerging cocoa science, which is a challenge we take very seriously at Mars."
Cocoapro® cocoa powder is used in Dove® Dark Chocolate, as well as in the new heart-healthy snack CocoaViaTM.
Elizabeth Schreiber | EurekAlert!