Diabetes may be bad for the brain, especially if you are overweight.
Researchers studied 50 overweight and 50 normal weight people in the early stages of Type 2 diabetes. The scientists performed M.R.I. examinations of their brains and psychological tests of memory, reaction time and planning. Those with diabetes scored worse than the healthy controls on tests of memory and reaction times.
M.R.I. scans revealed significant differences in brain areas related to memory, planning and the visual processing of information. Compared with the controls, those with Type 2 diabetes had more severe thinning of the cortex and more white matter abnormalities. Overweight people with diabetes had more brain deterioration than diabetic people of normal weight.
Ref:
http://www.diabetologia-journal.org/