Format

Send to

Choose Destination
Am J Clin Nutr. 2016 Mar;103(3):694-702. doi: 10.3945/ajcn.115.125690. Epub 2016 Feb 3.

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.

Author information

1
Department of Nutrition, Norwich Medical School, University of East Anglia, Norwich, United Kingdom.
2
Department of Nutrition, Norwich Medical School, University of East Anglia, Norwich, United Kingdom a.cassidy@uea.ac.uk.

Abstract

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 isoflavones (80-mg aglycone equivalents) on arterial stiffness [carotid-femoral pulse-wave velocity (cfPWV)], blood pressure, endothelial function (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 μmol/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.

KEYWORDS:

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

PMID:
26843154
PMCID:
PMC4763500
DOI:
10.3945/ajcn.115.125690
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center