Habitual Flavonoid Intake and Endothelial Function in Healthy Humans

Objective: Endothelial function, as measured by noninvasive techniques, is known to vary widely within populations. Our study was designed to test the hypothesis that this variation is determined in large part by a person's habitual dietary intake of flavonoids. Methods: This was an analytical study examining the relationship between endothelial function and dietary flavonoids in 19 healthy older adults (mean age 72 years). The study took place in the inpatient Clinical Research Center of the Brigham and Women's Hospital. Habitual flavonoid intake was assessed via a focused food frequency questionnaire. Endothelial function, measured as the reactive hyperemia response to 1 dose of flavonoid-rich cocoa, was recorded with a plethysmographic device via peripheral arterial tonometry (PAT). Results: Background flavonoid intake and the reactive hyperemia PAT (RH-PAT) response were significantly correlated (r = 0.7, p = 0.001); subjects with higher habitual flavonoid intake showed a significantly greater RH-PAT response than did lower consumers. PAT response to cocoa was also significantly correlated with simultaneous flavanol concentration in the blood (r = 0.5, p = 0.03). Conclusion: Individual variation in endothelial function among healthy older people, measured as PAT response to flavonoid-rich cocoa, is highly dependent upon usual daily flavonoid consumption. These data raise the possibility that the consumption of fruits and vegetables dictates basal endothelial function, likely related to their flavonoid content and influence on nitric oxide.