An isoflavone metabolite reduces arterial stiffness and blood pressure in overweight men and postmenopausal women.
OBJECTIVE
Isoflavones reduce arterial stiffness, a predictor of cardiovascular events. Whether metabolites of isoflavones have similar bioactivity is unknown. The effect of supplemental trans-tetrahydrodaidzein (THD) a metabolite of daidzein on pulse wave velocity (PWV), a measure of arterial stiffness was tested in overweight men and postmenopausal women.


METHODS
25 subjects, 11 postmenopausal women, 14 men (age, 57 [7] years; body mass index, 30.3 [4.7]kg/m(2); mean [S.D.]) participated in a double-blind, randomized, cross-over trial of THD versus placebo.


METHODS
2 weeks run-in followed by either THD 1g daily or placebo, each intervention 5 weeks. Aorta-femoral artery PWV, blood pressure and plasma lipids were measured after run-in, THD and placebo.


RESULTS
PWV was significantly reduced (signifying diminished central arterial stiffness): medians (25th and 75th%), placebo 9.9 m/s (8.7, 11.1), THD 8.8m/s (7.9, 10.9); RM ANOVA P=0.023, with Tukey procedure P<0.05. Systolic blood pressure was significantly reduced: means (S.D.), placebo 125.6 (14.7), THD 121.3 (12.2)mmHg; Tukey P<0.05. Plasma cholesterol, triglyceride and LDL cholesterol did not differ significantly. Absorption of THD >80% substantially exceeded that of parent isoflavones.


CONCLUSIONS
A metabolite normally formed after consumption of isoflavones (formononetin, daidezein), taken orally, reduced blood pressure and central arterial stiffness indicating reduced cardiovascular risk.
Nestel
Paul
P
Baker Heart Research Institute Wynm Domain, Melbourne, Australia. paul.nestel@baker.edu.au <paul.nestel@baker.edu.au>
Fujii
Akihiko
A
Zhang
Lei
L
D001158:Arteries / Q000502:physiology; D001794:Blood Pressure / Q000187:drug effects; D002318:Cardiovascular Diseases / Q000517:prevention & control; D018592:Cross-Over Studies; D004034:Diet Surveys; D019587:Dietary Supplements; D004311:Double-Blind Method; D004548:Elasticity; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000493:pharmacokinetics / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D050177:Overweight; D017698:Postmenopause; D011673:Pulsatile Flow / Q000187:drug effects*
D007529:Isoflavones; C433164:tetrahydrodaidzein