Effects of Obesity and Low and High Isoflavones in Soy Protein Concentrate Diet on Liver Steatosis

Abstract

Abstract Objectives To examine the role of isoflavones levels in soy protein diets on protection against Non-Alcoholic Fatty Liver Disease (NAFLD) in obese rat model (8 weeks of feeding). Methods 42 six-week old lean (n = 21) and obese (n = 21) Zucker rats were randomly assigned to one of 3 dietary groups: casein diet (C = control), soy protein with low isoflavones (LIF), or soy protein with high isoflavones (HIF) for 8 weeks (n = 7 rats/group). Rats were weighed twice weekly. After 8 weeks, all rats were sacrificed and livers taken for histopathological analysis. Results Obese rats gained significantly more weight (P < 0.0001) than lean rats for all three diet groups, with no significant difference between obese (O) LIF vs. OHIF groups (P = 0.19). Body weight was higher in OHIF (717 g) than in OLIF and OC (694 and 620, respectively). No significant difference between LC, LLIF and LHIF (P between 0.3 and 0.6) was found. Liver steatosis scores were significantly higher in obese rats compared to lean rats (P < 0.001). In addition, differences in the steatosis scores between OC vs. OHIF (P < 0.0001) were more significant than differences between OC vs. OLIF (P = 0.01), and OLIF vs. OHIF (P = 0.01) groups, showing the protective effect against liver steatosis exerted by soy protein concentrate with higher isoflavones. Conclusions We found that soy protein concentrate protects against liver steatosis and protection is more significant with higher concentration of isoflavones. Funding Sources USDA.