Background: Disorders in lipid metabolism and increases of serum lipid and lipoprotein levels have been associated with postmenopausal complications. Some studies have demonstrated that isoflavones and soy proteins could have useful effects on serum lipid and lipoprotein levels however, there are a few reports about the effects of total soy extract on serum lipid and lipoproteins. This study was carried out to evaluate the effect of methanolic soy extract on serum levels of lipid and lipoproteins in ovariectomized rat.

Materials and Methods: In this study 40 female rats were allocated randomly into 4 equal groups: 1) sham 2) ovariectomized 3) treatment and 4) control-gavage. The animals in treatment group received 60 mg/kg soy extract in drinking water using gavage for 28 days. At the end of the treatment, serum concentrations of total cholesterol, triglyceride, LDL, HDL and VLDL were determined.

Results: Results showed that administration of total soy extract can improve the serum concentrations of lipid and lipoproteins in treatment group. Moreover, the study revealed a significant difference between the sham group and the other groups in serum concentrations of VLDL and triglyceride (P<0.05).

Conclusion: Soy extract administration can have a positive effect on serum lipid and lipoprotein levels in ovariectomized rats.