Abstract
We investigated the effect of lactic fermented soymilk in improving hepatic lipid metabolism in rats fed a high fat and high cholesterol diet. Male Sprague-Dawley rats, aged 7 weeks, were fed a very high lipid diet (VC diet) or moderately high lipid diet (MC diet) for 5 weeks. The VC diet contained 30 % triacylglycerol (TG) and 0.5 % cholesterol ; for VF diet (very high lipid diet with fermented soymilk), 25.0 % of the VC diet was replaced with fermented soymilk. The MC diet contained 15 % TG and 0.125 % cholesterol ; for MF diet (moderately high lipid diet with fermented soymilk), 22.2 % of the MC diet was replaced with fermented soymilk. Only hepatic crude lipid and cholesterol contents were significantly suppressed in the VF group, whereas plasma total cholesterol (TC) and TG levels, as well as hepatic crude lipid, cholesterol and TG contents were significantly suppressed in the MF group. There was no down-regulation of hepatic lipid metabolism-related gene expression in the VF group ; in contrast, the expression of FAS was down-regulated in the MF group. These results suggested that the effect of fermented soymilk in improving lipid metabolism was small in rats fed the VC diet, likely due to reduced hepatic metabolic function caused by lipid overloading, whereas ingestion of fermented soymilk effectively suppressed the accumulation of hepatic lipid and the elevation of plasma lipid levels in rats fed a MC diet.
