![]() |
|
|
Department of Nutrition Science, Faculty of Applied Bioscience, Tokyo University of Agriculture, 11-1 Sakuragaoka, Setagaya, Tokyo 156-8502 Japan
2To whom correspondence should be addressed. E-mail: swatanab{at}nodai.ac.jp.
Clinical trials have noted hypocholesterolemic effects of soy protein intake, but the components responsible are not known. This meta-analysis of 8 randomized controlled trials was conducted to more precisely evaluate the effects of isoflavones on blood LDL cholesterol concentration independently of soy protein level. PubMed was searched for English-language "randomized controlled trial" articles published from 1966 to 2003 that described the effects of soy protein isolate (SPI) intake with measured isoflavone levels on blood lipids in humans using the search terms "soy protein," "isoflavones," and "cholesterol." From 31 articles identified by the search, 8 articles (with 10 low vs. high isoflavone comparisons) were selected for the meta-analysis. Subjects in each comparison consumed similar dietary fat, cholesterol, and fiber; the reported body weight of subjects did not change significantly during treatment. Serum LDL cholesterol concentration in subjects who consumed SPI (mean 50 g/d) with high isoflavone content (mean intake 96 mg/d) decreased by 0.15 mmol/L (95% CI: 0.08 to 0.23 mmol/L; P < 0.0001) compared with those who consumed the same SPI level with low isoflavone content (mean intake 6 mg/d). Decreases in serum LDL cholesterol concentration in hypercholesterolemic and normocholesterolemic subjects were 0.18 mmol/L (95% CI: 0.01 to 0.35 mmol/L; P = 0.03) and 0.14 mmol/L (95% CI: 0.06, 0.23 mmol/L; P = 0.0008), respectively. With identical soy protein intake, high isoflavone intake led to significantly greater decreases in serum LDL cholesterol than low isoflavone intake, demonstrating that isoflavones have LDL cholesterollowering effects independent of soy protein.
KEY WORDS: isoflavones LDL cholesterol soy protein meta-analysis
This article has been cited by other articles:
![]() |
A. Orgaard and L. Jensen The Effects of Soy Isoflavones on Obesity Experimental Biology and Medicine, September 1, 2008; 233(9): 1066 - 1080. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. A Thorp, P. R. Howe, T. A Mori, A. M Coates, J. D Buckley, J. Hodgson, J. Mansour, and B. J Meyer Soy food consumption does not lower LDL cholesterol in either equol or nonequol producers Am. J. Clinical Nutrition, August 1, 2008; 88(2): 298 - 304. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Hooper, P. A Kroon, E. B Rimm, J. S Cohn, I. Harvey, K. A Le Cornu, J. J Ryder, W. L Hall, and A. Cassidy Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials Am. J. Clinical Nutrition, July 1, 2008; 88(1): 38 - 50. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. J Powles, A. Howell, D G. Evans, E. V McCloskey, S. Ashley, R. Greenhalgh, J. Affen, L. A. Flook, and A. Tidy Red clover isoflavones are safe and well tolerated in women with a family history of breast cancer Menopause Int, March 1, 2008; 14(1): 6 - 12. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. P. Konhilas and L. A. Leinwand The Effects of Biological Sex and Diet on the Development of Heart Failure Circulation, December 4, 2007; 116(23): 2747 - 2759. [Full Text] [PDF] |
||||
![]() |
C. D. Gardner, M. Messina, A. Kiazand, J. L. Morris, and A. A. Franke Effect of Two Types of Soy Milk and Dairy Milk on Plasma Lipids in Hypercholesterolemic Adults: A Randomized Trial J. Am. Coll. Nutr., December 1, 2007; 26(6): 669 - 677. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Kokubo, H. Iso, J. Ishihara, K. Okada, M. Inoue, S. Tsugane, and for the JPHC Study Group Association of Dietary Intake of Soy, Beans, and Isoflavones With Risk of Cerebral and Myocardial Infarctions in Japanese Populations: The Japan Public Health Center Based (JPHC) Study Cohort I Circulation, November 27, 2007; 116(22): 2553 - 2562. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y.-H. Chan, K.-K. Lau, K.-H. Yiu, S.-W. Li, H.-T. Chan, S. Tam, X.-O. Shu, C.-P. Lau, and H.-F. Tse Isoflavone intake in persons at high risk of cardiovascular events: implications for vascular endothelial function and the carotid atherosclerotic burden Am. J. Clinical Nutrition, October 1, 2007; 86(4): 938 - 945. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Clerici, K. D. R. Setchell, P. M. Battezzati, M. Pirro, V. Giuliano, S. Asciutti, D. Castellani, E. Nardi, G. Sabatino, S. Orlandi, et al. Pasta Naturally Enriched with Isoflavone Aglycons from Soy Germ Reduces Serum Lipids and Improves Markers of Cardiovascular Risk J. Nutr., October 1, 2007; 137(10): 2270 - 2278. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Li, O. Mezei, and N. F. Shay Human and Murine Hepatic Sterol-12-{alpha}-Hydroxylase and Other Xenobiotic Metabolism mRNA Are Upregulated by Soy Isoflavones J. Nutr., July 1, 2007; 137(7): 1705 - 1712. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. M Steinberg Soybeans or soymilk: does it make a difference for cardiovascular protection? Does it even matter? Am. J. Clinical Nutrition, April 1, 2007; 85(4): 927 - 928. [Full Text] [PDF] |
||||
![]() |
K. Taku, K. Umegaki, Y. Sato, Y. Taki, K. Endoh, and S. Watanabe Soy isoflavones lower serum total and LDL cholesterol in humans: a meta-analysis of 11 randomized controlled trials Am. J. Clinical Nutrition, April 1, 2007; 85(4): 1148 - 1156. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Azadbakht, M. Kimiagar, Y. Mehrabi, A. Esmaillzadeh, M. Padyab, F. B Hu, and W. C Willett Soy inclusion in the diet improves features of the metabolic syndrome: a randomized crossover study in postmenopausal women Am. J. Clinical Nutrition, March 1, 2007; 85(3): 735 - 741. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. W. Erdman Jr., D. Balentine, L. Arab, G. Beecher, J. T. Dwyer, J. Folts, J. Harnly, P. Hollman, C. L. Keen, G. Mazza, et al. Flavonoids and Heart Health: Proceedings of the ILSI North America Flavonoids Workshop, May 31-June 1, 2005, Washington, DC J. Nutr., March 1, 2007; 137(3): 718S - 737S. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Ye, M. Renouf, S.-O. Lee, C. C. Hauck, P. A. Murphy, and S. Hendrich High Urinary Isoflavone Excretion Phenotype Decreases Plasma Cholesterol in Golden Syrian Hamsters Fed Soy Protein J. Nutr., November 1, 2006; 136(11): 2773 - 2778. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. K Nies, A. A Cymbala, S. L Kasten, D. G Lamprecht, and K. L Olson Complementary and Alternative Therapies for the Management of Dyslipidemia Ann. Pharmacother., November 1, 2006; 40(11): 1984 - 1992. [Abstract] [Full Text] [PDF] |
||||
![]() |
O. Mezei, Y. Li, E. Mullen, J. S. Ross-Viola, and N. F. Shay Dietary isoflavone supplementation modulates lipid metabolism via PPAR{alpha}-dependent and -independent mechanisms Physiol Genomics, September 14, 2006; 26(1): 8 - 14. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. K. Melby, M. Lock, and P. Kaufert Culture and symptom reporting at menopause Hum. Reprod. Update, September 1, 2005; 11(5): 495 - 512. [Abstract] [Full Text] [PDF] |
||||