Dark chocolate may help restore flexibility to arteries and prevent white blood cells from sticking to the walls of blood vessels, but increasing flavanol content will not affect these effects and may even put consumers off, say researchers.
The research, published in The FASEB Journal, saw 44 middle-aged, overweight men consuming 70 grams of chocolate per day over a period of four weeks. The participants were split between those who were given specially produced dark chocolate with high flavanol chocolate and regular dark chocolate, with both types of chocolate having similar cocoa content.
Before and after the trials the researchers looked at indicators of vascular health including flow-mediated dilation (FMD) augmentation index (AIX), leukocyte count, plasma cytokines, and leukocyte cell surface molecules.
The findings showed that a four week chocolate intake increased FDM by 1% and decreased AIX by 1%. It also decreased leukocyte cell count, decreased plasma cytokines, and decreased leukocyte adhesion, with no difference between the two different chocolate types.
Diederik Esser, one of the scientists at Wageningen University behind the study, said: "We provide a more complete picture of the impact of chocolate consumption in vascular health and show that increasing flavanol content has no added beneficial effect on vascular health."
After looking at the reception of flavanol-enriched dark chocolate in comparison to normal chocolate by overweight, middle-aged men, the researchers said that the bitter taste of the flavanol chocolate may demotivate consumers.
Health claims and heart health
The scientists said most research so far had concentrated on blood flow-mediated dilation only – for which Barry Callebaut currently holds exclusive rights to an EFSA-approved health claim. The claim reads: “Cocoa flavanols help maintain endothelium-dependent vasodilation, which contributes to normal blood flow.”
This latest research sought to address other factors relevant to endothelial health, such as inflammation and leukocyte adhesion, which the scientists say has hardly been addressed. The study also addressed the influence of increased flavanols on taste profile and therefore motivation to eat it.
“As the predominantly consumed cocoa-derived product is chocolate, increasing chocolate flavanol content might be of importance to improve vascular health and thereby to decrease cardiovascular disease risk at the opulation level. However, flavanols have been described as astringent and bitter. Increasing the flavanol content of chocolate might therefore affect taste perception, hence affecting the motivation to consume such chocolates,” the researchers said.
After looking at the sensory profiles and motivation scores to eat chocolate, Esser said that increased flavanol content clearly affected taste and therefore the motivation to eat those chocolates. “So the dark side of chocolate is a healthy one," he said.
Gerald Weissmann, managing director and editor-in-chief of the journal, commented: "The effect that dark chocolate has on our bodies is encouraging not only because it allows us to indulge with less guilt, but also because it could lead the way to therapies that do the same thing as dark chocolate but with better and more consistent results.”
Source: FASEB Journal
Published online ahead of print, doi:10.1096/fj.13-239384
“Dark chocolate consumption improves leukocyte adhesion factors and vascular function in overweight men”
Authors: D. Esser, M. Mars, E. Oosterink, A. Stalmach, M. Müller and L. A. Afman