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

Abstract

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 6 SD carotid-femoral pulse wave velocity, which reflects central aortic stiffness, was statistically significantly lower after consumption of GFJ (7.36 6 1.15 m/s) than after consumption of the matched control drink without flavanones (7.70 6 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.Am J Clin Nutr 2015;102:66-74.

Habitual intake of anthocyanins and flavanones and risk of cardiovascular disease in men,

“…To our knowledge, only a handful of placebo-controlled trials with flavanones have been conducted to date. The first long-term trial, a 6-mo flavanone intervention trial with grapefruit juice (containing 210 mg naringenin glycosides/d) in healthy postmenopausal women improved arterial stiffness (19). In another 2-mo intervention with flavanone-rich orange juice, global cognitive function was improved (55), which is consistent with effects previously observed in animal models (44).…”

Effects and Mechanisms of Fruit and Vegetable Juices on Cardiovascular Diseases

“…Several studies were conducted to assess the effects of clear apple juice, cloudy apple juices, squeezed orange juice, and grapefruit juice on blood pressure in healthy adults or adults with hypercholesterolemia and hypertriglyceridemia. No effect of any of these interventions was found on SBP or DBP [53,54,55]. In addition, two studies assessing the effects of vegetable juice showed that either beetroot juice or low sodium vegetable juice could not decrease blood pressure in individuals with type 2 diabetes or in people with metabolic syndrome [60,63].…”

“…No significant differences were found in plasma total antioxidant capacity, antioxidant vitamins, LDL oxidation, or erythrocyte antioxidant enzyme activity [83]. In another study [53], the antioxidant effect of grapefruit was investigated, but results showed that oxidative stress was not affected after consumption of grapefruit juice.…”

“…Serum levels of vascular endothelial adhesion molecule 1 (VCAM-1) were markedly down-regulated by pomegranate juice while those of E-selection were up-regulated. Additionally, in the study of Habauzit et al [53], the effects of consuming grapefruit flavanone on vascular function were investigated. Central aortic stiffness was statistically significantly lowered after consumption of grapefruit juice.…”

“…No evidence has shown that orange juice alone could lower inflammatory biomarkers [100]. Additionally, in the study of Habauzit et al [53], grapefruit juice was investigated. The result showed that biomarkers of inflammation were not affected by flavanones (naringenin glycosides) in grapefruit juice.…”