Acute benefits of the microbial-derived isoflavone metabolite equol on arterial stiffness in men prospectively recruited according to equol producer phenotype: a double-blind randomized controlled trial

作者：Hazim Sara; Curtis Peter J; Schar Manuel Y; Ostertag Luisa M; Kay Colin D; Minihane Anne Marie; Cassidy Aedin^*

来源：American Journal of Clinical Nutrition, 2016, 103(3): 694-702.

DOI：10.3945/ajcn.115.125690

• CVD risk
• isoflavone
• flavonoids
• vascular function
• equol producer phenotype
• arterial stiffness

Background: There is much speculation with regard to the potential cardioprotective benefits of equol, a microbial-derived metabolite of the isoflavone daidzein, which is produced in the large intestine after soy intake in 30% of Western populations. Although cross-sectional and retrospective data support favorable associations between the equol producer (EP) phenotype and cardiometabolic health, few studies have prospectively recruited EPs to confirm this association.
Objective: The aim was to determine whether the acute vascular benefits of isoflavones differ according to EP phenotype and subsequently investigate the effect of providing commercially produced S-(-)equol to non-EPs.
Design: We prospectively recruited male EPs and non-EPs (n = 14/group) at moderate cardiovascular risk into a double-blind, placebo controlled crossover study to examine the acute effects of soy isofiavones (80-mg aglycone equivalents) on arterial stiffness [carotid-femoral pulse-wave velocity (cfPWV)], blood pressure, endothelial measured by using the EndoPAT 2000; Itamar Medical), and nitric oxide at baseline (0 h) and 6 and 24 h after intake. In a separate assessment, non-EPs consumed 40 mg S-(-) equol with identical vascular measurements performed 2 h after intake.
Results: After soy intake, cfPWV significantly improved in EPs at 24 h (cfPWV change from 0 h: isoflavone, -0.2 +/- 0.2 m/s; placebo, 0.6 +/- 0.2 m/s; P < 0.01), which was significantly associated with plasma equol concentrations (R = -0.36, P = 0.01). No vascular effects were observed in EPs at 6 h or in non-EPs at any time point. Similarly, no benefit of commercially produced S-(-)equol was observed in non-EPs despite mean plasma equol concentrations reaching 3.2 mu mol/L.
Conclusions: Acute soy intake improved cfPWV in EPs, equating to an 11-12% reduced risk of cardiovascular disease if sustained. However, a single dose of commercially produced equol had no cardiovascular benefits in non-EPs. These data suggest that the EP phenotype is critical in unlocking the vascular benefits of equol in men, and long-term trials should focus on confirming the implications of EP phenotype on cardiovascular health. This trial was registered at clinicaltrials.gov as NCT01530893.

• 出版日期2016-3