Effect of isoflavones on lipids and bone turnover markers in menopausal women

The purpose of this analysis was to compare the effects of two dietary supplements derived from red clover to placebo on lipids and bone turnover markers in symptomatic menopausal women.

The study was a 12-week randomized, double-blind, placebo-controlled trial. Two hundred and fifty-two menopausal women ages 45-60 years experiencing > or =35 hot flashes per week were randomly assigned to Promensil (82 mg total isoflavones), Rimostil (57.2 mg total isoflavones), or placebo. Primary outcome measures were mean absolute changes for HDL-cholesterol, serum osteocalcin, and urinary N-telopeptide. Secondary outcome measures were mean changes of total cholesterol, LDL-cholesterol, the ratio of HDL- to LDL-cholesterol, and triglycerides.

Ninety-eight percent of participants completed the 12-week protocol. Women taking Rimostil or Promensil compared to those taking placebo had greater mean increases in HDL-cholesterol; however, this change was small in magnitude (<2 mg/dl) and did not reach significance. There was a significant decrease in triglyceride levels among women taking Rimostil (14.4 mg/dl, P = 0.02) or Promensil (10.9 mg/dl, P = 0.05) compared to those taking placebo. The decrease was primarily among women with elevated baseline triglyceride levels (P for interaction = 0.009). There were no differences in mean changes of total cholesterol, LDL-cholesterol, or the ratio of HDL- to LDL-cholesterol among treatment groups. There were no statistically significant differences among treatment groups for bone turnover markers.

Compared with placebo, both of the supplements containing isoflavones decrease levels of triglycerides in symptomatic menopausal women; however, this effect is small in magnitude.