Effects of the phytoestrogen genistein on cardiovascular risk factors in postmenopausal women

Objective: The phytoestrogen genistein has been shown to be the most efficacious in clinical and experimental studies. We studied whether genistein treatment affects some cardiovascular risk markers in postmenopausal women. Design: Sixty healthy postmenopausal women, who were 52 to 60 years of age, were enrolled in a 6-month double-blind, placebo-controlled, randomized study. After a 4-week stabilization on a standard fat-reduced diet, participants were randomly assigned to receive either genistein (n = 30; 54 mg/d) or placebo (n = 30). At baseline and after a 6-month treatment, we measured fasting glucose, insulin, insulin resistance (HOMA-IR), osteoprotegerin (OPG), fibrinogen, and sex hormone-binding globulin (SHBG). Results: By comparison with placebo, genistein treatment decreased significantly fasting glucose (genistein = - 8.7 +/- 2.3%; placebo = 3.2 +/- 2.3%; P < 0.001), fasting insulin (genistein = - 12 +/- 3.33%; placebo = 36 +/- 3.29%; P < 0.001), and HOMA-IR (genistein = - 14 +/- 5.8%; placebo = 42 +/- 0.6%; P < 0.001). After genistein-treatment, fibrinogen decreased (genistein = 3.18 +/- 0.12 g/L; placebo = 3.83 +/- 0.04 g/L; P < 0.001) with respect to placebo. In the genistein group, serum OPG was lower (-2 +/- 0.3%) than in placebo (9 +/- 1.5%; P < 0.001), and serum SHBG was higher (63 +/- 3.8 nmol/L) compared with placebo (53 +/- 2.9 nmol/L; P < 0.05). Conclusion: Our study suggests that genistein may have a favorable effect on some cardiovascular markers.