Effects of Bean Consumption on the Relationship between Lipid Profile and Bone Mineral Density in Ovariectomized Rats

Abstract

The beneficial effects of soy protein and isoflavones on cardiovascular-related disease have been well documented. This study investigated the effects of various legume consumptions on lipid profiles and the relationship between serum lipids and bone mineral density in ovariectomized rats. Forty-two female Sprague-Dawley rats were either sham-operated (Sham, n=7) or surgically ovariectomized, and then fed a regular AIN-93M diet (OVX, n=7) or AIN-93M containing soybeans (OS, n=7), mung beans (OM, n=7), cowpeas (OC, n=7) or adzuki beans (OA, n=7) for 10 weeks. The levels of serum total cholesterol, triglyceride, HDL-cholesterol, and LDL-cholesterol were measured. The relationships between lipid profiles and bone mineral density (BMD) or bone mineral content (BMC) were also compared. Serum triglyceride level was significantly lower in the OM group than the OVX and OC group. The level of total cholesterol was significantly lower in the OC group than the OVX and other bean consumed groups. The level of HDL-cholesterol was significantly lower in the OC and OA groups than in the OVX, OS and OM groups, while no significant differences between the OVX group and the OS and OM groups. The level of LDL-cholesterol was significantly higher in the OVX group compared with the Sham group. Among the bean consumption groups, the concentration of LDL-cholesterol was significantly lower in the OC group than in the OVX and OS groups. Total cholesterol levels were negatively correlated with BMD and BMC of the spine in the OVX, OS, and OC groups, as well as BMC of the femur in the OS group and BMD of the tibia in the OC group. Serum triglyceride levels were also negatively correlated with BMD of the femur in the OVX group. In conclusion, although mung bean and cowpea had some associations between total cholesterol on BMD or BMC at various skeletal sites, the results of this study is not clearly whether beneficial effects of consuming legumes on the relationship between lipid profile and bone mineral density. Further investigation is needed into the lipid mechanism and bone metabolism of legumes.