Topical Area: Dietary Bioactive Components
The obesity epidemic is continuing to grow in the United States and world for past two decades. There is a link between obesity and chronic diseases development such as diabetes, cardiovascular disease, certain types of cancer and liver diseases. Previously, we reported that obesity caused a significant increase liver steatosis and feeding soy protein isolate (SPI) reduced liver steatosis. The mechanism of SPI protection against liver steatosis is less known. We hypothesize that soy protein diet will reduce development of liver steatosis caused by obesity in part by changing methylation status. The objective of the present study was to investigate the effects of SPI feeding on liver metabolic methylation status using obese zucker rat model.
After one week of acclimation, five weeks old female lean and obese Zucker rats (n=8/group) were randomly fed AIN-93-G diet with either casein (CAS as control) or SPI as source of protein for 22 weeks. Rats were weighted twice per week. Liver sample metabolites concentrations were measured using HPLC with Electrochemical Detection and LC-MS.
Results : Our results shows that; 1) obesity increased body weight significantly (P< 0.001) for both CAS and SPI diets; 2) Obese SPI-fed rats significantly (P< 0.001) reduced liver steatosis compared to obese CAS-fed rats. Also, our results show that liver metabolic profile in lean SPI-fed rats significantly (P< 0.025) increased SAM/SAH ratio (methylation ratio) compare to CAS-fed rats. Obese SPI-fed rats significantly (P< 0.001) decrease level of Homocysteine in liver and increase significantly (P< 0.001) Methionine/Homocysteine ratio.
In summary we showed that SPI diet can reduce liver steatosis by changing methylation status and improved metabolism of Homocysteine, toxic intracellular compound, through remethylation to Methionine.
Funding Sources :
Arkansas Children’s Research Institute’s University Medical Group Fund grant program and Arkansas
UAMS, Department of Dietetics and Nutrition and Arkansas Children's Research Institute
Department of Pathology, University of Arkansas for Medical Sciences
Arkansas children's Resaerch Institute
Arkansas Children's Research Institute