Diabetes is a group of diseases characterized by high blood glucose levels that result from the body’s inability to produce or use insulin. Insulin is necessary for the body to be able to use glucose for energy. After food consumption, the body breaks down the sugars and starches into glucose, which is the basic fuel for the cells. Insulin takes the sugar from the blood into the cells. When glucose builds up in the blood instead of going into cells, it can lead to diabetes complications.
Research has shown that type I and II diabetes is associated with decline in cognitive skills and increased risk of Alzheimer’s disease.
Impact on the brain
The results of several studies indicate that deterioration in brains of elderly people suffering from chronic diabetes is more extensive than in brains of their healthier peers. In some studies the decline in brain volume has been significant only if uncontrolled diabetes is accompanied by hypertension but in others the deterioration is significant even after the influence of hypertension has been taken into account.
Association with Alzheimer’s disease
A prospective study followed over 800 individuals over 55 years old, for up to 9 years. In this period 151 of the participants developed Alzheimer’s disease. The results showed that people with diabetes had 65% increased risk of developing Alzheimer’s disease compared to those without diabetes mellitus.
Many other studies have found associations between diabetes and dementia, both of the Alzheimer’s and vascular type.
Impact on cognitive abilities
The impact of diabetes on cognitive functions has been studied for over 80 years and lots of studies have confirmed that chronic diabetes is accompanied by negative changes in cognitive functions. Those studies are not in agreement as to what type of cognitive ability suffers the most.
One study of middle-aged individuals who had suffered from type II diabetes for less than 10 years, showed that the decline in brain-volume was restricted to hippocampus and the cognitive impairment was restricted to memory impairment with preservation of other cognitive domains (which makes sense as the hippocampus is a vital organ in memory). The poorer the metabolic control was, the more extensive the volumic decline in hippocampus. The authors suggest that the first impact of diabetes II on the brain is seen in the medial temporal lobes (where the hippocampus resides).
Lifestyle measurements can prevent type II diabetes in up to 60–70% of people. Here is a video from Youtube.com on the positive effects of combined aerobic and resistance exercise on glycemic/blood sugar control in people with type 2 diabetes. Interestingly, this is the same conclusion found in studies on the impact of exercise on cognitive skills (see here), i.e. combined strength- and aerobic training seems to have more profound effect than aerobic training alone.
More information on diabetes here: http://www.diabetes.org/
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