Effects of Fermented Soymilk on Lipid Metabolism in Rats Fed a High Fat Diet

Soy foods are known to be effective for the amelioration of lipid metabolism. We investigated the effect of fermented soymilk on lipid metabolism in rats fed a high fat diet. Male Sprague-Dawley rats aged 7 weeks were fed either a control diet (AIN-93G), high fat diet including 28.5% powdered beef tallow (60% fat energy), or test diet where 24.1% of the high fat diet was replaced with fermented soymilk (10% soy protein in diet) for 5 weeks. Although it was previously reported that the plasma triglyceride level in rats fed a normal diet (AIN-93G) was not decreased by the ingestion of fermented soymilk. it was found in the present study that the level of rats fed a high fat diet containing fermented soymilk was significantly suppressed compared with those of rats fed a high fat diet. Although the hepatic cholesterol level in rats fed a high fat diet was reduced by the ingestion of fermented soymilk, a significant decrease in plasma total cholesterol level, to the level in rats fed a normal diet, was not observed. These lipid metabolism-modulation effects in rats fed a high fat diet seem to depend on the physiological action of fermented soymilk supplemented to the diet. (Received May 22. 2012: Accepted Jun. 26, 2012)