Effects of isoflavone dietary supplementation on cardiovascular risk factors in type 2 diabetes.

A diet supplemented with soy protein and isoflavones has been shown to reduce cardiovascular risk factors in postmenopausal women with type 2 diabetes. However, it remains unclear which component is responsible for these effects. Our aim was to determine whether the addition of isoflavones alone modifies cardiovascular disease risk markers in this group of patients. Cardiovascular disease (CVD) is the leading cause of mortality in women in developed countries (1), and women with diabetes are four times more likely to die from CVD than men (2). Among other factors, postmenopausal estrogen depletion, greater insulin resistance, and dyslipidemia (3,4) may contribute to high risk of accelerated CVD. Modification of lifestyle is important to reduce CVD risk factors and delay progression of type 2 diabetes–associated complications. In particular, the addition of oral supplements, such as soy products, as part of a healthy diet has attracted recent interest because of their beneficial effects on lipid profiles (5–10). However, scant information is available on the effects of soy in individuals with type 2 diabetes (11–13), who are at higher risk due to hyperlipidemia, lower HDL levels, and abnormalities in LDL/lipoprotein composition (14). It also remains unclear whether a beneficial effect can be attributed to the soy protein or isoflavones. We have shown that soy protein combined with isoflavones can improve glycemic control, insulin resistance, and lipids in patients with type 2 diabetes (11). Therefore, our aim was to determine if this effect was due to the isoflavone component alone.