Soy isoflavones improve plasma lipids in normocholesterolemic, premenopausal women

Barbara E. Merz-Demlow, Alison M. Duncan, Kerry E. Wangen, Xia Xu, Timothy P. Carr, William R. Phipps, Mindy S. Kurzer

Research output: Contribution to journalArticlepeer-review

212 Scopus citations


Background: Soy consumption is known to reduce plasma total cholesterol and LDL cholesterol in hypercholesterolemic subjects, but the responsible soy components and the effects in normocholesterolemic subjects remain unclear. Objective: The effects of soy isoflavone consumption on plasma total cholesterol, HDL-cholesterol, LDL-cholesterol, triacylglycerol, apolipoprotein A-I, apolipoprotein B, and lipoprotein(a) concentrations and on LDL peak particle diameter were examined in normocholesterolemic, premenopausal women. Design: Thirteen healthy, normocholesterolemic, free- living, premenopausal female volunteers took part in this randomized, crossover-controlled trial. Each subject acted as her own control. Three soy isoflavone intakes (control: 10.0 ± 1.1; low: 64.7 ± 9.4; and high: 128.7 ± 15.7 mg/d), provided as soy protein isolate, were consumed for 3 menstrual cycles each. Total cholesterol, HDL cholesterol, LDL cholesterol, and triacylglycerol were measured over the menstrual cycle. Apolipoprotein A-I, apolipoprotein B, lipoprotein(a), and LDL peak particle diameter were evaluated in the midluteal phase. Results: Total cholesterol, HDL- cholesterol, and LDL-cholesterol concentrations changed significantly across menstrual cycle phases (P < 0.005). During specific phases of the cycle, the high-isoflavone diet lowered LDL cholesterol by 7.6-10.0% (P < 0.05), the ratio of total cholesterol to HDL cholesterol by 10.2% (P < 0.005), and the ratio of LDL to HDL cholesterol by 13.8% (P < 0.002). Conclusions: Isoflavones significantly improved the lipid profile across the menstrual cycle in normocholesterolemic, premenopausal women. Although of small magnitude, these effects could contribute to a lower risk of developing coronary heart disease in healthy people who consume soy over many years.

Original languageEnglish (US)
Pages (from-to)1462-1469
Number of pages8
JournalAmerican Journal of Clinical Nutrition
Issue number6
StatePublished - Jun 2000


  • Apoli poprotein A-I
  • Apolipoprotein B
  • Cholesterol
  • HDL
  • Isoflavone
  • LDL
  • Lipids
  • Lipoprotein(a)
  • Menstrual cycle
  • Phytoestrogen
  • Soy
  • Triacylglycerol
  • Women


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