Antecedent intake of traditional Asian-style diets exacerbates pancreatic β-cell function, growth and survival after Western-style diet feeding in weaning male rats

The prevalence of type 2 diabetes has been rapidly increasing in conjunction with the westernization of diet patterns in Asia. We determined whether the antecedent consumption of traditional Asian-style diets (ADs) deteriorates insulin action, insulin secretion and pancreatic β-cell mass after subsequent imposition of the diabetogenic challenge of Western-style diets (WDs) in weaning male Sprague–Dawley rats. Rats were provided AD (a low-fat and plant protein diet), WD (a high-fat and animal protein diet) or a control diet (CD) (a low-fat and animal protein diet) for 12 weeks. After 12 weeks, the groups were divided into two subsets; one set of the groups continued to consume their previous diets of WD, AD and CD for another 12 weeks, and the second set was divided into three groups represented by a switch in their designated diets from WD to AD, AD to WD and CD to WD. Whole-body glucose disposal rates and GLUT4 contents in soleus muscles were lower in WD regardless of the antecedent protein sources. The first-phase insulin secretion was higher in the CD group than in the other groups, whereas the second phase was lowered with AD consumption as antecedent and/or present diets. Asian-style diet and AD-WD intake did not compensate for insulin resistance due to the failure of β-cell expansion via decreased proliferation. These findings suggest that the antecedent consumption of AD possibly accelerates and augments the development of glucose dysregulation via decreased insulin secretion capacity and pancreatic β-cell mass when the diets switch to WD.