Twenty-three men and 18 postmenopausal women with elevated cholesterol levels participated in the study. The subjects rotated through three 1-month diets that were all very low in saturated fat. In the control diet, the main protein-containing foods such as meats and fish were replaced with low-fat dairy products and egg substitute. Low-fat soymilk and a variety of soy-based meat substitutes such as soy hot dogs and tofu burgers took the place of the usual protein sources in the two soy protein-containing diets. Body weight, blood lipids, and blood pressure were measured before and after each diet. After each soy diet, total cholesterol, the ratio of low-density lipoprotein (LDL) to high-density lipoprotein (HDL) cholesterol, homocysteine concentrations, and estimated overall cardiovascular risk were lower than they were after the control diet. Additionally, serum concentrations of LDL were lower after the high-isoflavone diet. The only significant difference between the sexes was a tendency toward reduced blood pressure in men after the high-soy isoflavone diet.
A wide range of small but beneficial effects were associated with the substitution of soy-protein for animal protein foods in the subjects' diets that did not differ significantly between the high- and low-isoflavone diets, indicating that even low-isoflavone soy foods can produce favorable results. Two unique aspects of the study were that a variety of soy-protein foods were used to substitute for the usual protein sources and that the soy diets continued to improve the subjects' blood lipid profiles even after dietary saturated fat consumption was maximally reduced.
Jenkins, David JA et al. Effects of high- and low-isoflavone soyfoods on blood lipids, oxidized LDL, homocysteine, and blood pressure in hyperlipidemic men and women. Am J Clin Nutr 2002;76:365-72.
This media release is provided by The American Society for Clinical Nutrition to provide current information on nutrition-related research. This information should not be construed as medical advice. If you have a medical concern, consult your doctor. To see the complete text of this article, please go to:
http://www.faseb.org/ajcn/August/13019.Setchell.pdf
For more information, please contact: cyril.kendall@utoronto.ca
Journal
American Journal of Clinical Nutrition