Type 3 Diabetes: Link Between Alzheimer's Disease and Diabetes

Most people have heard of type 1 diabetes, an autoimmune illness in which the body fails to generate insulin, and type 2 diabetes, in which the body does not use insulin efficiently. In recent years, the term "type 3 diabetes" has been used in the health media and literature to refer to Alzheimers disease, because the neurodegenerative disease is connected to insulin resistance in the brain, which is a feature of type 2 diabetes (1^✔ ✔Trusted Source
Insulin Resistance and Oxidative Stress in the Brain: What's New?

Go to source). However, most doctors are unlikely to adopt the phrase for diagnostic purposes anytime soon.

Why is Alzheimer's Disease Referred to as Type 3 Diabetes?

"It's more of a research term than a medical term," explains Guojun Bu, Ph.D., a neurology professor and associate director of the Mayo Clinic's Center for Regenerative Medicine in Jacksonville, Florida. It's a method of identifying the growing body of studies into the links between insulin resistance in the brain and neurodegenerative disorders such as cognitive decline, Alzheimer's disease, and other types of dementia (2^✔ ✔Trusted Source
Alzheimer's Disease as Type 3 Diabetes: Common Pathophysiological Mechanisms between Alzheimer's Disease and Type 2 Diabetes

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How Do Type 2 Diabetes and Alzheimer's Disease Affect the Body and Brain?

The body does not use insulin correctly in persons with type 2 diabetes, which is a hormone that helps carry glucose (blood sugar) to the muscles, fat, and cells for energy. Insulin resistance is the medical term for this condition. According to the NIDDK, the pancreas initially attempts to compensate by producing more insulin, but for many people, this production eventually becomes insufficient, and the amount of glucose in the blood climbs to harmful levels. According to the NIDDK, type 2 diabetes commonly develops in adults over the age of 45 and is caused by a combination of genetic predispositions, environment, lifestyle, nutrition, and other risk factors.

According to the Alzheimer's Association, Alzheimer's disease is a brain ailment that is also associated with advancing age, typically affecting those aged 65 and older. It is the most frequent, but not the sole, cause of dementia. Individuals with the condition undergo increasing memory loss, behavioral abnormalities, and loss of bodily functions as a result of brain nerve cell damage and death (3^✔ ✔Trusted Source
Comprehensive Review on Alzheimer's Disease: Causes and Treatment

Go to source).

People with Alzheimer's live four to eight years on average following diagnosis, with others living up to 20 years. Autopsies of Alzheimer's patients reveal a specific pattern of deposits of two proteins (4^✔ ✔Trusted Source
Key Peptides and Proteins in Alzheimer's Disease

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• Beta-Amyloid: This protein fragment accumulates and forms plaques in the gaps between nerve cells.
• Tau Tangles: They form when Tau accumulates within cells in the form of twisted strands.

Researchers are still working to determine what causes Alzheimer's disease. According to Heather M. Snyder, Ph.D., vice president of medical and scientific operations at the Alzheimer's Association in Durham, North Carolina, a study reveals that the immune system and hormone pathways may be implicated in the development of the disorder. However, experts are increasingly investigating a link between diabetes and insulin resistance.

“Individuals who have diabetes have an increased risk of Alzheimer’s disease and related dementias in later life,” says Dr. Snyder. “The exact mechanisms are not fully understood. However, when we look at the way that our brains are processing energy, it seems that that process changes in people with diabetes. It could be due to the way type 2 diabetes affects the brain's capacity to metabolize glucose and respond to insulin.”

References:

1. Insulin Resistance and Oxidative Stress in the Brain: What's New? - (https://pubmed.ncbi.nlm.nih.gov/30781611/)
2. Alzheimer's Disease as Type 3 Diabetes: Common Pathophysiological Mechanisms between Alzheimer's Disease and Type 2 Diabetes - (https://pubmed.ncbi.nlm.nih.gov/35269827/)
3. Comprehensive Review on Alzheimer's Disease: Causes and Treatment - (https://pubmed.ncbi.nlm.nih.gov/33302541/)
4. Key Peptides and Proteins in Alzheimer's Disease - (https://pubmed.ncbi.nlm.nih.gov/30605056/)

Source-Medindia