Insulin (Canadian discovery) controls blood sugar. High blood sugar is a problem for many people when insulin is less effective in the body. Often the body becomes resistant to insulin as you get older and gain weight. Insulin transports sugar into the cells, and when it cannot, sugar stays high in the blood stream. The pancreas works overtime to make more and more insulin to meet the sugar demands of active cells. Insulin levels soar in the blood. This condition is called insulin resistance, and the technical term for high insulin in the blood is hyperinsulinemia; high sugar is the blood is called hyperglycaemia.
Often hyperinsulinemia is seen decades before the onset of Alzheimer’s dementia, and is possibly causing mild cognitive impairment and age-related cognitive decline. The mechanism is paradoxical. When insulin in high in the blood, it is low in the brain. Low insulin (hypoinsulinemia) in the brain deprives it of insulin’s role of promoting nerve growth and synapse development. In other words, hypoinsulinemia limits neuroplasticity and nerve growth, and it also leads to neuroinflammation. This is the set-up for brain conditions like dementia, depression, and other neuropsychiatric diseases. The hardest hit areas of the brain are the prefrontal cortex (planning) and hippocampus (memory). Not surprisingly these are also areas damaged in dementia and depression.
Naturally, eating well and avoiding sugary and processed foods can limit sugar spikes and keep insulin levels under control. This is beneficial to the brain. Insulin resistance can be reduced by exercise, diet, medications, and some herbs.