Equol status and blood lipid profile in hyperlipidemia after consumption of diets containing soy foods.
BACKGROUND
Recent analyses have challenged the effectiveness of soy foods as part of a cardiovascular risk reduction diet.


OBJECTIVE
The objective of the study was to show whether equol status determines the effectiveness of soy foods to lower LDL cholesterol and to raise HDL cholesterol.


METHODS
Eighty-five hypercholesterolemic men and postmenopausal women (42 men, 43 women) participated in 1 of 3 studies that represented a range of soy interventions and that followed the same general protocol at a Canadian university hospital research center. Soy foods were provided for 1 mo at doses of 30-52 g/d for the 3 studies as follows: 1) soy foods with either high-normal (73 mg/d) or low (10 mg/d) isoflavones, 2) soy foods with or without a prebiotic to enhance colonic fermentation (10 g polyfructans/d), or 3) soy foods with a low-carbohydrate diet (26% carbohydrate). Studies 1 and 2 were randomized controlled crossover trials, and study 3 was a parallel study.


RESULTS
The separation of the group into equol producers (n = 30) and nonproducers (n = 55) showed similar reductions from baseline in LDL cholesterol (-9.3 ± 2.5% and -11.1 ± 1.6%, respectively; P = 0.834), with preservation of HDL cholesterol and apolipoprotein A-I only in equol producers compared with reductions in nonproducers (HDL cholesterol: +0.9 ± 2.7% compared with -4.3 ± 1.1%, P = 0.006; apolipoprotein A-I: -1.0 ± 1.1% compared with -4.7 ± 1.0%; P = 0.011). The amount of urinary equol excreted did not relate to the changes in blood lipids.


CONCLUSIONS
Soy foods reduced serum LDL cholesterol equally in both equol producers and nonproducers. However, in equol producers, ~35% of our study population, soy consumption had the added cardiovascular benefit of maintaining higher HDL-cholesterol concentrations than those seen in equol nonproducers. This trial was registered at clinicaltrials.gov as NCT00877825 (study 1), NCT00516594 (study 2), and NCT00256516 (study 3).
Clinical Nutrition & Risk Factor Modification Center, St Michael's Hospital, Toronto, Canada.
Julia M W
JM
Wong
Cyril W C
CW
Kendall
Augustine
A
Marchie
Zhen
Z
Liu
Ed
E
Vidgen
Candice
C
Holmes
Chung-Ja
CJ
Jackson
Robert G
RG
Josse
Paul B
PB
Pencharz
A Venketeshwer
AV
Rao
Vladimir
V
Vuksan
William
W
Singer
David J A
DJ
Jenkins
D000368:Aged; D016632:Apolipoprotein A-I / Q000097:blood; D002318:Cardiovascular Diseases / Q000517:prevention & control; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood*; D018592:Cross-Over Studies; D004032:Diet; D060754:Equol / Q000097:blood*; D005260:Female; D006801:Humans; D006949:Hyperlipidemias / Q000097:blood* / Q000178:diet therapy / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017698:Postmenopause; D056692:Prebiotics / Q000032:analysis; D012307:Risk Factors; D045730:Soy Foods
D016632:Apolipoprotein A-I; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D056692:Prebiotics; D060754:Equol