A diet based on wheat bread baked with lactic acid improves glucose tolerance in hyperinsulinaemic Zucker (fa/fa) rats

In the present study, the objective was to evaluate the long-term metabolic impact of adding lactic acid to a bread-based diet in obese, hyperinsulinaemic Zucker (fa/fa) rats. All diets were based on a white wheat bread, and the lactic acid was added either prior to, or after the baking process. In addition, a diet with addition of Lactobacillus plantarum 299v was included to investigate the possible impact of probiotic lactic acid bacteria, in the absence of lactic acid. The intervention period was fourteen days and oral glucose tolerance tests (OGTTs) were performed before and after the intervention. Glucose, insulin and glucagon were measured during both OGTTs. Other parameters studied were blood lipids (total cholesterol and triglycerides) and liver cholesterol. The intervention period with the wheat bread baked in the presence of lactic acid improved glucose tolerance as judged from a 51% reduction (P=0.007) in the total glycaemic area. In contrast, there was no such improvement with the diet where lactic acid was added after baking or with addition of probiotic bacteria. No differences were seen between groups in insulin, blood lipids or liver cholesterol following the intervention. It is concluded that bread baked in the presence of lactic acid improves glucose metabolism in obese and hyperinsulinaemic Zucker rats.