Soy-isoflavone-enriched foods and markers of lipid and glucose metabolism in postmenopausal women: interactions with genotype and equol production.
BACKGROUND
The hypocholesterolemic effects of soy foods are well established, and it has been suggested that isoflavones are responsible for this effect. However, beneficial effects of isolated isoflavones on lipid biomarkers of cardiovascular disease risk have not yet been shown.


OBJECTIVE
The objective was to investigate the effects of isolated soy isoflavones on metabolic biomarkers of cardiovascular disease risk, including plasma total, HDL, and LDL cholesterol; triacylglycerols; lipoprotein(a); the percentage of small dense LDL; glucose; nonesterified fatty acids; insulin; and the homeostasis model assessment of insulin resistance. Differences with respect to single nucleotide polymorphisms in selected genes [ie, estrogen receptor alpha (XbaI and PvuII), estrogen receptor beta (AluI), and estrogen receptor beta(cx) (Tsp509I), endothelial nitric oxide synthase (Glu298Asp), apolipoprotein E (Apo E2, E3, and E4), cholesteryl ester transfer protein (TaqIB), and leptin receptor (Gln223Arg)] and with respect to equol production were investigated.


METHODS
Healthy postmenopausal women (n = 117) participated in a randomized, double-blind, placebo-controlled, crossover dietary intervention trial. Isoflavone-enriched (genistein-to-daidzein ratio of 2:1; 50 mg/d) or placebo cereal bars were consumed for 8 wk, with a wash-out period of 8 wk before the crossover.


RESULTS
Isoflavones did not have a significant beneficial effect on plasma concentrations of lipids, glucose, or insulin. A significant difference between the responses of HDL cholesterol to isoflavones and to placebo was found with estrogen receptor beta(cx) Tsp509I genotype AA, but not GG or GA.


CONCLUSIONS
Isoflavone supplementation, when provided in the form and dose used in this study, had no effect on lipid or other metabolic biomarkers of cardiovascular disease risk in postmenopausal women but may increase HDL cholesterol in an estrogen receptor beta gene-polymorphic subgroup.
Hall
Wendy L
WL
Hugh Sinclair Unit of Human Nutrition, School of Food Biosciences, University of Reading, Reading, United Kingdom. wendy.hall@kcl.ac.uk
Vafeiadou
Katerina
K
Hallund
Jesper
J
Bugel
Susanne
S
Reimann
Manja
M
Koebnick
Corinna
C
Zunft
H-J Franz
HJ
Ferrari
Marika
M
Branca
Francesco
F
Dadd
Tony
T
Talbot
Duncan
D
Powell
Jonathan
J
Minihane
Anne-Marie
AM
Cassidy
Aedin
A
Nilsson
Maria
M
Dahlman-Wright
Karin
K
Gustafsson
Jan-Ake
JA
Williams
Christine M
CM
D000368:Aged; D001483:Base Sequence; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D002318:Cardiovascular Diseases / Q000097:blood / Q000453:epidemiology; D008076:Cholesterol, HDL / Q000097:blood* / Q000187:drug effects; D018592:Cross-Over Studies; D004311:Double-Blind Method; D060754:Equol; D047629:Estrogen Receptor beta / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005527:Food, Fortified; D005838:Genotype; D006801:Humans; D007328:Insulin / Q000097:blood; D007529:Isoflavones / Q000008:administration & dosage* / Q000096:biosynthesis / Q000652:urine; D050356:Lipid Metabolism / Q000187:drug effects*; D017270:Lipoprotein(a) / Q000097:blood; D008875:Middle Aged; D008969:Molecular Sequence Data; D048789:Phytoestrogens / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D017698:Postmenopause; D012307:Risk Factors; D045730:Soy Foods
C007610:4',7-dihydroxy-3,4-dihydroisoflavone; D015415:Biomarkers; D001786:Blood Glucose; D008076:Cholesterol, HDL; D047629:Estrogen Receptor beta; D007328:Insulin; D007529:Isoflavones; D017270:Lipoprotein(a); D048789:Phytoestrogens; D060754:Equol