The use of soy protein containing isoflavones-a phytoestrogen or weak form of naturally occurring estrogen-can improve atherogenic lipoprotein profiles in postmenopausal women and effectively reduce two strong, independent indicators of coronary heart disease.
According to a study by Johns Hopkins researchers, both the low-density lipoprotein cholesterol elevation (LDL-C) and the low-density lipoprotein particle number (LDL-P) were decreased in healthy postmenopausal women with borderline LDL-C who took a dietary supplement of soy protein each day for six weeks. In the randomized “Beneficial Effects of Soy Trial” (BEST), 216 Caucasian and African-American women received a daily dose of either 20 grams of isolated soy protein containing isoflavones or a placebo of 20 grams of protein from casein.
In comparison to the women who were given the placebo, those taking the soy protein experienced significantly greater decreases in LDL-C and LDL-P. Differences in age, race, changes in other lipoproteins, dietary saturated fat intake, and weight had little or no impact on the BEST findings.
“Previous trials have demonstrated a variety of aspects regarding the benefits of soy proteins,” says principal investigator Jerilyn K. Allen, RN, ScD, associate dean for research at the Johns Hopkins University School of Nursing (JHUSON). “But those studies included small numbers of postmenopausal women and virtually none included sufficient African-American women.” Allen added, “Our findings could have significant public health implications for postmenopausal women and will add substantially to the limited body of knowledge of the effects of soy.”
The study was conducted at the Johns Hopkins University School of Nursing and funded by the National Heart, Lung, and Blood Institute. Allen’s co-investigators were Diane Becker, RN, ScD, and Peter Kwiterovich, Jr. MD, both of Johns Hopkins University School of Medicine.
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Revision date: June 22, 2011
Last revised: by Janet A. Staessen, MD, PhD