Clinical studies have shown that the disrupted insulin signaling associated with diabetes is correlated with not only reduced cognitive function, but a number of cognitive diseases including vascular dementia and Alzheimer’s disease.
In the study, the control group of non-diabetic rats were given a standard chow diet, while the experimental rats, which were of a species well-established as genetic models of Type 2 diabetes, were administered curcumin in their chow at a dose of 5g/kg of food. The rats in the experimental group were also exposed to exercise in which they climbed a latter with weights secured to their tails in a series of trials that specified whether an exercise was considered complete.
Additionally, come diabetic rats were given exercise without curcumin, and another group of diabetic rats received neither exercise nor curcumin.
The diabetic rats that received curcumin and exercise had significantly lower mean body weight than the diabetic rats in both the non-therapeutic control group, and the diabetic group that received exercise only. Additionally, curcumin and exercise combined achieved lower fasting blood glucose levels and HOMA-IR levels than even the non-diabetic control group.
Across the metrics of fasting blood glucose levels, body weight, and HOMA-IR levels, curcumin and exercise appeared to improve the health of diabetic rats at a greater rate than exercise alone. Interestingly, the curcumin + exercise group of diabetic rats appeared to have lower triglycerides than the non-therapeutic group, but this benefit was not seen through exercise alone.
Tissue samples also showed significantly greater reductions in the biomarkers associated with diabetes-caused ER stress in the rats that were administered both exercise and curcumin, compared to exercise alone.
Following analysis of the metabolic impacts in this experiment, the researchers evaluated whether the combination of curcumin and exercise, shown to reduce ER stress caused by diabetes, would result in improvements to cognition.
Using the Morris water maze test, which evaluates the time it takes for rats to reach an endpoint based on memory retention, rats that were given exercise and curcumin showed significantly better performances than any other diabetic group of rats.
Researchers concluded that this study highlighted that curcumin could play a role in the therapy of diabetes-associated cognitive dysfunction. However, the study had several limitations, they added.
“First, the study focused on the effects of exercise of OLETF (diabetes model) rats for the cognitive function, which does not provide the experimental group of OLETF rats with curcumin alone. Nevertheless, exercise is a major factor of lifestyle for adults in cognitive function, which also included to investigate the effect of curcumin in the study.”
Secondly, the researchers did not provide the data of histology or ER stress in the brains of the OLETF rats. Additionally, as a bioactive compound, physiological differences in each rat could vary how well the rats absorbed the curcumin. Nevertheless, the results provided evidence that exercise and curcumin (administered at the amount of 5g per diet) improved the weight loss, glucose homeostasis, lipid profiles, and cognition of rats with diabetes at significant rates.