QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Greaves, K. A. Articles by Wagner, J. D. Search for Related Content PubMed PubMed Citation Articles by Greaves, K. A. Articles by Wagner, J. D.

---

Article

Consumption of Soy Protein Reduces Cholesterol Absorption Compared to Casein Protein Alone or Supplemented with an Isoflavone Extract or Conjugated Equine Estrogen in Ovariectomized Cynomolgus Monkeys¹

Wake Forest University School of Medicine, Department of Pathology, Section on Comparative Medicine, Winston-Salem, NC 27157-1040

²To whom correspondence should be addressed.

Dietary intake of soy protein is associated with reductions in plasma cholesterol. Isoflavones are thought to be active components of soy and responsible for the beneficial effects because of their structural similarities to estrogen. The purposes of this study were to determine if i) soy protein or a semipurified soy extract, rich in isoflavones, is responsible for improving the lipid profile and ii) altered intestinal cholesterol metabolism is one mechanism for hypocholesterolemic effects. Ovariectomized adult female cynomolgus monkeys (40) were assigned to groups fed diets containing i) casein-lactalbumin (CAS) ii) intact soy protein (SOY), iii) CAS plus an isoflavone-rich semipurified soy extract similar in isoflavone content as SOY (ISO) or iv) CAS plus conjugated equine estrogen (CEE) for 20 wk. Cholesterol absorption was determined using the fecal isotope ratio method. Bile acid excretion was measured using the 3-hydroxysteroid dehydrogenase assay. The SOY group had significantly lower total- and VLDL + LDL-cholesterol compared to the other three groups and significantly higher HDL-cholesterol compared to the CAS and CEE groups. Cholesterol absorption was significantly lower in the SOY group compared to the other groups, but bile acid excretion was not significantly affected. The hypocholesterolemic effect of soy protein appears to be mediated in part by decreased cholesterol absorption. The semipurified soy extract, rich in isoflavones, added to casein protein did not have lipid-lowering effects. Other components of soy such as saponins, phytic acid or the amino acid composition may be involved in the hypocholesterolemic effects seen in this study.

KEY WORDS: • cholesterol absorption • cynomolgus monkeys • isoflavones • menopause • soy protein.

This article has been cited by other articles:

				K. Kavanagh, M. A. Davis, L. Zhang, M. D. Wilson, T. C. Register, M. R. Adams, L. L. Rudel, and J. D. Wagner Estrogen Decreases Atherosclerosis in Part by Reducing Hepatic Acyl-CoA:Cholesterol Acyltransferase 2 (ACAT2) in Monkeys Arterioscler Thromb Vasc Biol, October 1, 2009; 29(10): 1471 - 1477. [Abstract] [Full Text] [PDF]

				S.-C. Yang, S.-M. Liu, H.-Y. Yang, Y.-H. Lin, and J.-R. Chen Soybean Protein Hydrolysate Improves Plasma and Liver Lipid Profiles in Rats Fed High-Cholesterol Diet J. Am. Coll. Nutr., October 1, 2007; 26(5): 416 - 423. [Abstract] [Full Text] [PDF]

				Y. Ma, D. Chiriboga, B. C. Olendzki, R. Nicolosi, P. A. Merriam, and I. S. Ockene Effect of Soy Protein Containing Isoflavones on Blood Lipids in Moderately Hypercholesterolemic Adults: A Randomized Controlled Trial J. Am. Coll. Nutr., August 1, 2005; 24(4): 275 - 285. [Abstract] [Full Text] [PDF]

				M. Lacroix, C. Gaudichon, A. Martin, C. Morens, V. Mathe, D. Tome, and J.-F. Huneau A long-term high-protein diet markedly reduces adipose tissue without major side effects in Wistar male rats Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2004; 287(4): R934 - R942. [Abstract] [Full Text] [PDF]

				C. Atkinson, W. Oosthuizen, S. Scollen, A. Loktionov, N. E. Day, and S. A. Bingham Modest Protective Effects of Isoflavones from a Red Clover-Derived Dietary Supplement on Cardiovascular Disease Risk Factors in Perimenopausal Women, and Evidence of an Interaction with ApoE Genotype in 49-65 Year-Old Women J. Nutr., July 1, 2004; 134(7): 1759 - 1764. [Abstract] [Full Text]

				Y. Lin, G. W. Meijer, M. A. Vermeer, and E. A. Trautwein Soy Protein Enhances the Cholesterol-Lowering Effect of Plant Sterol Esters in Cholesterol-Fed Hamsters J. Nutr., January 1, 2004; 134(1): 143 - 148. [Abstract] [Full Text] [PDF]

				S. Madani, J. Prost, M. Narce, and J. Belleville VLDL Metabolism in Rats Is Affected by the Concentration and Source of Dietary Protein J. Nutr., December 1, 2003; 133(12): 4102 - 4106. [Abstract] [Full Text] [PDF]

				T. Song, S.-O. Lee, P. A. Murphy, and S. Hendrich Soy Protein With or Without Isoflavones, Soy Germ and Soy Germ Extract, and Daidzein Lessen Plasma Cholesterol Levels in Golden Syrian Hamsters Experimental Biology and Medicine, October 1, 2003; 228(9): 1063 - 1068. [Abstract] [Full Text] [PDF]

				E. Gianazza, I. Eberini, A. Arnoldi, R. Wait, and C. R. Sirtori A Proteomic Investigation of Isolated Soy Proteins with Variable Effects in Experimental and Clinical Studies J. Nutr., January 1, 2003; 133(1): 9 - 14. [Abstract] [Full Text] [PDF]

				W. Pan, K. Ikeda, M. Takebe, and Y. Yamori Genistein, Daidzein and Glycitein Inhibit Growth and DNA Synthesis of Aortic Smooth Muscle Cells from Stroke-Prone Spontaneously Hypertensive Rats J. Nutr., April 1, 2001; 131(4): 1154 - 1158. [Abstract] [Full Text]