Effects of isoflavone-supplemented soy yogurt on lipid parameters and atherosclerosis development in hypercholesterolemic rabbits: a randomized double-blind study.
BACKGROUND
There is increasing interest in natural treatments to control dyslipidemia and reduce the risk of cardiovascular disease. Previous studies have demonstrated the beneficial effects of soy yogurt fermented with Enterococcus faecium CRL 183 and of dietary isoflavones on the lipid profile. The purpose of the present study was to investigate the effects of isoflavone-supplemented soy yogurt, fermented with E. faecium CRL183, on lipid parameters and atherosclerosis development in rabbits with induced hypercholesterolemia.


METHODS
Forty-eight rabbits were randomly assigned to eight groups fed on the following diets for 60 days: C - control; IY - isoflavone-supplemented soy yogurt; H - hypercholesterolemic (1.0% cholesterol wt/wt diet); HY - hypercholesterolemic plus soy yogurt; HIY - hypercholesterolemic plus isoflavone-supplemented soy yogurt; HP - hypercholesterolemic plus placebo; HI - hypercholesterolemic plus isoflavone and HE - hypercholesterolemic plus pure culture of E. faecium CRL 183. Serum lipids and autoantibodies against oxLDL (oxLDL Ab) were analyzed on days 0, 30 and 60 of the treatment and the atherosclerotic lesions were quantified at the end of the experiment.


RESULTS
Soy yogurt, soy yogurt supplemented with isoflavones and placebo promoted significant reductions in total cholesterol level (38.1%, 27.0% and 26.6%, respectively). Significant increases in serum HDL-C concentration relative to group H were detected in animals that ingested soy yogurt, with or without the isoflavone supplement (55.2%), E. faecium culture (43.3%) or placebo (35.8%). Intake of soy yogurt and soy yogurt supplemented with isoflavones prevented the rise of oxLDL Ab during the study period. The extent of atherosclerosis in the thoracic and abdominal aortas was reduced in the HIY, HY and HP groups. However, when the whole aorta was analyzed, animals treated with soy yogurt supplemented with isoflavones exhibited the greatest reduction (51.4%, P < 0.05) in atherosclerotic lesion area, compared to group H.


CONCLUSIONS
Soy yogurt could be consumed as an alternative means of reducing the risk of cardiovascular disease by improving the lipid profile and inhibiting oxLDL Ab formation. Our findings also suggest that isoflavone supplementation may enhance the antiatherosclerotic effect of soy yogurt.
Cavallini
Daniela C U
DC
Department of Food & Nutrition, Faculty of Pharmaceutical Sciences, São Paulo State University, Araraquara, SP, Brazil. daniducavallini@ig.com.br
Abdalla
Dulcinéia S P
DS
Vendramini
Regina C
RC
Bedani
Raquel
R
Bomdespacho
Laura Q
LQ
Pauly-Silveira
Nadiége D
ND
de Valdez
Graciela F
GF
Rossi
Elizeu A
EA
D000818:Animals; D050197:Atherosclerosis / Q000097:blood / Q000178:diet therapy / Q000188:drug therapy / Q000473:pathology / Q000517:prevention & control*; D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D007529:Isoflavones / Q000494:pharmacology*; D050356:Lipid Metabolism / Q000187:drug effects*; D011817:Rabbits; D011897:Random Allocation; D013025:Glycine max / Q000737:chemistry*; D015014:Yogurt
D008078:Cholesterol, LDL; D007529:Isoflavones; D002784:Cholesterol