Jennifer L Wojcik1,2, Jessay G Devassy1,2, Yinghong Wu1,2, Peter Zahradka1,2,3, Carla G Taylor1,2,3, Harold M Aukema1,2. 1. Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, Manitoba, Canada. 2. Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada. 3. Department of Physiology and Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada.
Abstract
OBJECTIVE: High-protein diets are being promoted to reduce insulin resistance and hepatic steatosis in metabolic syndrome. Therefore, the effect of protein source in high-protein diets on reducing insulin resistance and hepatic steatosis was examined. METHODS: Fa/fa Zucker rats were provided normal-protein (15% of energy) casein, high-protein (35% of energy) casein, high-protein soy, or high-protein mixed diets with animal and plant proteins. RESULTS: The high-protein mixed diet reduced area under the curve for insulin during glucose tolerance testing, fasting serum insulin and free fatty acid concentrations, homeostatic model assessment index, insulin to glucose ratio, and pancreatic islet cell area. The high-protein mixed and the high-protein soy diets reduced hepatic lipid concentrations, liver to body weight ratio, and hepatic steatosis rating. These improvements were observed despite no differences in body weight, feed intake, or adiposity among high-protein diet groups. The high-protein casein diet had minimal benefits. CONCLUSIONS: A high-protein mixed diet was the most effective for modulating reductions in insulin resistance and hepatic steatosis independent of weight loss, indicating that the source of protein within a high-protein diet is critical for the management of these metabolic syndrome parameters.
OBJECTIVE: High-protein diets are being promoted to reduce insulin resistance and hepatic steatosis in metabolic syndrome. Therefore, the effect of protein source in high-protein diets on reducing insulin resistance and hepatic steatosis was examined. METHODS: Fa/fa Zucker rats were provided normal-protein (15% of energy) casein, high-protein (35% of energy) casein, high-protein soy, or high-protein mixed diets with animal and plant proteins. RESULTS: The high-protein mixed diet reduced area under the curve for insulin during glucose tolerance testing, fasting serum insulin and free fatty acid concentrations, homeostatic model assessment index, insulin to glucose ratio, and pancreatic islet cell area. The high-protein mixed and the high-protein soy diets reduced hepatic lipid concentrations, liver to body weight ratio, and hepatic steatosis rating. These improvements were observed despite no differences in body weight, feed intake, or adiposity among high-protein diet groups. The high-protein casein diet had minimal benefits. CONCLUSIONS: A high-protein mixed diet was the most effective for modulating reductions in insulin resistance and hepatic steatosis independent of weight loss, indicating that the source of protein within a high-protein diet is critical for the management of these metabolic syndrome parameters.
Authors: William W French; Sami Dridi; Stephanie A Shouse; Hexirui Wu; Aubree Hawley; Sun-Ok Lee; Xuan Gu; Jamie I Baum Journal: Nutrients Date: 2017-06-08 Impact factor: 5.717