Oct. 4, 2002 -- Older women with diabetes may be able to lower their risk of heart disease by adding soy supplements to their diet. A new study shows the supplements reduced insulin resistance and lowered cholesterol levels in postmenopausal women with type 2 diabetes.
The study appears in the October issue of Diabetes Care.
According to researchers, people with type 2 diabetes are up to four times more likely to die from heart disease, and women with diabetes are four times as likely than men to die from heart disease. The risk of heart disease is especially high among postmenopausal women with diabetes due to the loss of estrogen and increased insulin resistance. Insulin resistance -- often the first sign of type 2 diabetes -- refers to how effectively the body uses insulin.
Previous studies have shown that a diet rich in soy protein, which contains estrogen-like substances called isoflavones, can reduce insulin resistance in animals. Some studies have also suggested that soy consumption can reduce the risk of heart disease. But researchers say that until now there has been little information on the effects of soy in postmenopausal women with type 2 diabetes.
In this study, 32 postmenopausal women with diet-controlled type 2 diabetes -- those taking no medications -- took either one 30-gram soy-protein supplement that contained 132 mg of isoflavones, or a placebo daily.
After 12 weeks, women who took the soy supplements lowered their total cholesterol levels by 4%, decreased their LDL "bad" cholesterol by 7%, and improved their blood sugar level. In addition, the soy helped reduce fasting insulin levels by 8% -- a sign of improved insulin function. No differences were found in HDL "good" cholesterol levels, weight, or blood pressure -- other major risk factors for heart disease.
Researchers say the improvement in insulin function without a change in weight suggests that soy was directly responsible for the positive effects found in these women.
Researcher Vijay Jayagopal, MRCP, of the department of medicine at the University of Hull in Hull, UK, and colleagues say these findings show that soy supplementation has a beneficial effect on both blood sugar control and other heart disease risk factors in these women -- at least in the short term.
They say more, long-term studies are needed to determine if these benefits last or if they lower the chance of having a heart attack and other heart-related problems in postmenopausal women. -->