Is Alzheimer’s disease a form of diabetes?

Research from the past decade shows strong links between Alzheimer’s disease, prediabetes and diabetes. According to some studies, 8 out of 10 people who develop dementia have problems with their blood sugar regulation. The Dietary Research Foundation intends to initiate a study that will evaluate whether a diet that lowers blood sugar can slow the progression of dementia.

The pharmaceutical industry has invested billions of dollars into the development of drugs that can slow down Alzheimer’s disease. For a long time, researchers believed that memory disturbances were caused by deposits in the brain of the protein beta-amyloid, commonly known as plaque. The goal so far has been to get rid of the plaque, but studies have repeatedly failed. More and more researchers now question whether the plaque in the brain is the actual cause of the disease.

One hypothesis that is growing stronger is that the brain is damaged by high blood sugar, and that it becomes resistant to insulin. Some scientists even want to call Alzheimer’s disease “Type 3 diabetes”: Alzheimer’s Disease Is Type 3 Diabetes–Evidence Reviewed. Studies of Alzheimer patients show that 8 out of 10 people have problems with blood sugar and that insulin resistance is associated with poorer cognitive performance (references below).

High blood sugar appears to accelerate the dementia process

A study of the elderly population in the borough of Kungsholmen in Stockholm also showed that poor blood sugar control appeared to accelerate the disease’s progression. For people with prediabetes or diabetes it took an average of 1.8 years for mild cognitive impairment to develop into full dementia. In the rest of the participants, dementia took 5 years to develop: Accelerated progression from mild cognitive impairment to dementia in people with diabetes.

In addition, studies have shown that mice who were given large doses of sugar water not only became overweight and developed insulin resistance, but also suffered from memory loss and deposits of beta-amyloid in the brain: Metabolic alterations induced by sucrose intake and Alzheimer’s disease promote similar brain mitochondrial abnormalities.

The strong link between elevated blood sugar and the development of dementia suggests that some kind of diet that lowers blood glucose might slow the progression of the disease. However, this has never been studied using good scientific methods. The Dietary Research Foundation wants to initiate such a study.

References:

Increased Risk of Type 2 Diabetes in Alzheimer Disease

Fasting Plasma Insulin, C-Peptide and Cognitive Change in Older Men without Diabetes: Results from the Physicians’ Health Study II

Hyperinsulinemia and risk of Alzheimer disease

Metabolic links between diabetes and Alzheimer’s disease

Alzheimer disease: Insulin resistance and AD—extending the translational path

Diabetes, impaired fasting glucose, and development of cognitive impairment in older women