Effects of soy protein on selected enzymes in tissues of rats fed a cholesterol diet

Soy protein, an important component of soybeans is unique among plant-based protein because of its associated isoflavones. Isoflavones are a group of compounds with variety of biological properties that may potentially benefit human health. Their actions in various tissues have motivated researchers to access the possible related mechanisms and functions. This study is aimed at determining the effect of soy protein on selected tissue enzymes (used as aids in early diagnosis of cardiovascular disease) in rats fed a cholesterol diet. 24 male Wistar albino rats were assigned randomly into three groups. The first group serving as control was placed on normal diet while groups two and three were fed diet containing 5% cholesterol and 5% cholesterol plus 5% soy protein, respectively. The animals were placed on their respective diet for 7 weeks and at weekly interval LDH, ALT, AST and γ-GT activities in the liver, kidney and heart were monitored. At the end of the study period, LDH, ALT, AST and γ-GT activities were substantially reduced in the liver, kidney and heart of rats fed soy protein plus cholesterol diet compared with those fed cholesterol diet without soy protein. These results indicate that soy protein reduces the accumulation of excess fat in the liver, kidney and heart and thus prevent cell death due to lipotoxicity. Key words:  Soy protein, cholesterol, diet, enzyme, lipotoxicity, cardiovascular disease.