Cinnamon counteracts the negative effects of a high fat/high fructose diet on brain insulin signaling and behavior

Abstract

Insulin resistance leads to memory and brain impairment. Cinnamon (CN) improves whole body insulin sensitivity but its effects in the brain are not known. Insulin signaling related gene expression in the brain and tests of behavior were measured in male Wistar rats fed a high fat/high fructose (HF/HFr) diet to induce insulin resistance, with or without CN, for 12 weeks. The HF/HFr diet induced an increase in genes coding for PTEN, AKT, amyloid precursor protein, tau, and glycogen synthase and a decrease in genes coding for the insulin receptor and insulin receptor substrates 1 and 2 in the cortex and hippocampus that was counteracted by feeding CN. The CN fed rats were more active and curious in a Y maze test then rats fed the control and HF/HFr diets. The HF/HFr diet fed rats showed greater anxiety in an elevated plus maze test that was lessened by feeding CN. Diet and CN effects on cognition were not significant. In summary, the negative effects of a HF/HFr diet on brain insulin signaling and behavior were alleviated by CN suggesting neuroprotective effects of CN associated with improved insulin sensitivity.(Funded by USDA/ARS/USA CRADA:58‐3K95‐7‐1184 and French PNRA 007)