Beneficial effects of soy phytoestrogen intake in postmenopausal women with type 2 diabetes.
OBJECTIVE
Phytoestrogen consumption has been shown to reduce risk factors for cardiovascular disease. Type 2 diabetes confers an adverse cardiovascular risk profile particularly in women after menopause. The aim of this study was to determine whether a dietary supplement with soy protein and isoflavones affected insulin resistance, glycemic control, and cardiovascular risk markers in postmenopausal women with type 2 diabetes.


METHODS
A total of 32 postmenopausal women with diet-controlled type 2 diabetes completed a randomized, double blind, cross-over trial of dietary supplementation with phytoestrogens (soy protein 30 g/day, isoflavones 132 mg/day) versus placebo (cellulose 30 g/day) for 12 weeks, separated by a 2-week washout period.


RESULTS
Compliance with the dietary supplementation was >90% for both treatment phases. When compared with the mean percentage change from baseline seen after 12 weeks of placebo, phytoestrogen supplementation demonstrated significantly lower mean values for fasting insulin (mean +/- SD 8.09 +/- 21.9%, P = 0.006), insulin resistance (6.47 +/- 27.7%, P = 0.003), HbA(1c) (0.64 +/- 3.19%, P = 0.048), total cholesterol (4.07 +/- 8.13%, P = 0.004), LDL cholesterol (7.09 +/- 12.7%, P = 0.001), cholesterol/HDL cholesterol ratio (3.89 +/- 11.7%, P = 0.015), and free thyroxine (2.50 +/- 8.47%, P = 0.004). No significant change occurred in HDL cholesterol, triglycerides, weight, blood pressure, creatinine, dehydroepiandrosterone sulfate, androstenedione, and the hypothalamic-pituitary-ovarian axis hormones.


CONCLUSIONS
These results show that dietary supplementation with soy phytoestrogens favorably alters insulin resistance, glycemic control, and serum lipoproteins in postmenopausal women with type 2 diabetes, thereby improving their cardiovascular risk profile.
D001786:Blood Glucose / Q000378:metabolism*; D001794:Blood Pressure; D001835:Body Weight; D002318:Cardiovascular Diseases / Q000517:prevention & control; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D003925:Diabetic Angiopathies / Q000517:prevention & control; D019587:Dietary Supplements; D004311:Double-Blind Method; D004968:Estrogens, Non-Steroidal / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006728:Hormones / Q000097:blood; D006801:Humans; D007529:Isoflavones; D008055:Lipids / Q000097:blood*; D010349:Patient Compliance; D018579:Patient Selection; D048789:Phytoestrogens; D008517:Phytotherapy; D010919:Placebos; D028321:Plant Preparations; D017698:Postmenopause; D013025:Glycine max
D001786:Blood Glucose; D004968:Estrogens, Non-Steroidal; D006442:Glycated Hemoglobin; D006728:Hormones; D007529:Isoflavones; D008055:Lipids; D048789:Phytoestrogens; D010919:Placebos; D028321:Plant Preparations