Effects of Isolated Isoflavonoids on Lipids, Lipoproteins, Insulin Sensitivity, and Ghrelin in Postmenopausal Women

The low cardiovascular risk in Asian women has been thought to result from high isoflavonoid intake. In a double-blind, randomized, placebo-controlled trial, we studied the effects of isolated isoflavonoids (114 mg/d) on lipids, lipoproteins, insulin sensitivity, and ghrelin in 56 nondiabetic postmenopausal women with a history of breast cancer. Isoflavonoid or placebo tablets were given for 3 months, and the treatment regimens crossed over after a 2-month washout period. The concentrations of total cholesterol, high- and low-density lipoprotein cholesterol, triglycerides, apolipoproteins B and A1, and lipoprotein (a) were not affected by isoflavonoids. However, during the isoflavonoid regimen, women with low-density lipoprotein cholesterol level above the median (4.20 mmol/liter) showed a rise [0.65 +/- 0.60 (sd) mmol/liter], which was statistically different from the fall during the placebo regimen (-0.45 +/- 0.67 mmol/liter, P = 0.009). Isoflavonoids did not affect insulin sensitivity as assessed by an oral 2-h glucose tolerance test (75 g). Changes in ghrelin levels differed (P = 0.048) during the isoflavonoid (-7.1 +/- 151 micromol/liter) and placebo regimens (+47.9 +/- 198 micromol/liter). In conclusion, we found no effects of isolated isoflavonoids on lipids, lipoproteins, or insulin sensitivity in postmenopausal women, implying no vascular benefit. Isoflavonoids may reduce ghrelin levels and thus hunger and weight.