Coffee Compounds Assist Heart Health

The cells that line blood vessels, known as the endothelium, perform many functions including to maintain elasticity of blood vessels and regulate the activity of immune cells. Endothelial function is measured by detecting transient increases in blood flow, a marker known as the reactive hyperemia index (RHI). Japanese researchers enrolled a group of healthy, non-diabetic men in a study in which each was randomly assigned to consume = a 75 g glucose load either with or without green coffee bean polyphenols. The team observed that blood glucose and insulin levels increased after both interventions, and there were no differences between the groups. However, the reactive hyperemia index rose significantly in the polyphenol group, as compared to their starting levels. The study authors conclude that: "These findings suggest that a single ingestion of [coffee polyphenols] improves peripheral endothelial function after glucose loading in healthy subjects.”