Flavanones protect from arterial stiffness in postmenopausal women consuming grapefruit juice for 6 mo: a randomized, controlled, crossover trial

Background: The consumption of citrus fruits is associated with health benefits. However, clinical data regarding the effects of grapefruit flavanone consumption on vascular function are lacking. Objective: The objective of the present study was to address the role of flavanones in the long-term effects induced by grapefruit juice (GFJ) consumption on vascular function in healthy postmenopausal women. Design: Forty-eight healthy postmenopausal women aged 50–65 y within 3–10 y since menopause, a body mass index (in kg/m ²) of 19–30, and a waist size >88 cm completed this double-blind, randomized, controlled, crossover trial. These volunteers were randomly assigned to consume 340 mL GFJ/d, providing 210 mg naringenin glycosides, or a matched control drink without flavanones for 6 mo each, with a 2-mo washout between beverages. The primary endpoint was the assessment of endothelial function in the brachial artery by using flow-mediated dilation. Blood pressure, arterial stiffness, and endothelial function in the peripheral arterial bed were also evaluated as indicators of vascular function. These measurements and blood collection for clinical biochemical markers were performed in overnight-fasted subjects before and after the 6-mo treatment periods. Results: The mean ± SD carotid-femoral pulse wave velocity, which reflects central aortic stiffness, was statistically significantly lower after consumption of GFJ (7.36 ± 1.15 m/s) than after consumption of the matched control drink without flavanones (7.70 ± 1.36 m/s), with a P value of 0.019 for the treatment effect. Endothelial function in macro- and microcirculation, blood pressure, anthropometric measures, glucose metabolism, and biomarkers of inflammation and oxidative stress were not affected by the intervention. Conclusions: Regular GFJ consumption by middle-aged, healthy postmenopausal women is beneficial for arterial stiffness. This effect may be related to flavanones present in grapefruit. This trial was registered at clinicaltrials.gov as NCT01272167.