Research from as early as 1983 has documented changes in blood insulin levels in Alzheimer’s disease. Fasting blood insulin and insulin response to a glucose challenge are elevated in individuals with Alzheimer’s. This process in which insulin is transported from the blood to the brain is a receptor-mediated process and the receptor of insulin CSF serum shows a subtle decrease with age. The research also found lower levels of CSF/serum in AD and higher blood and lower CSF insulin to be more prominent with disease progression. Although findings on cerebrospinal fluid (CSF) insulin vary, recent data indicates that individuals with Alzheimer’s disease are likely to have increased blood insulin levels.
