Why Is Alzheimer’s Disease Called Type 3 Diabetes?

Unraveling the link between glucose metabolism and brain health

A recent longitudinal study examined how glucose levels in early adulthood impact the risk of developing Alzheimer’s later in life.

Data from nearly 5000 participants (35–50 years old) over the course of 38 years were analyzed to determine correlations between metabolic markers and Alzheimer’s disease.

Individuals with higher blood glucose levels during middle adulthood had a 14.5% higher risk of developing Alzheimer’s disease later in life. But why might we observe this association between impaired glucose metabolism and deterioration of brain function?

How Can Defects in Glucose Metabolism Impair Brain Function?

The brain uses glucose as its primary energy source but can also use ketones under fasting conditions. High blood sugar coincides with a reduced ability to uptake glucose into the brain, making diabetes and obesity major risk factors for dementia.

ApoE4 is a gene that is strongly associated with an increased risk of developing Alzheimer’s later in life. Having one mutated copy doubles your risk, and having two mutated copies increases risk 10-fold.