Type 3 Diabetes and Dementia

Type 1 diabetes usually occurs in children when an autoimmune response destroys the insulin-producing cells in the pancreas such that the body can no longer regulate levels of blood sugar. Insulin therapy is required. Type 2 diabetes, the most common type of diabetes, occurs when the pancreas either does not produce enough insulin or the muscle, liver, and fat cells ignore the insulin and fail to remove such excess sugar from the blood. High insulin levels and high blood sugar raises the risk of heart disease, stroke, blindness, nerve damage, and amputation. Being overweight increases the risk of Type 2 diabetes. Type 3 diabetes1, coined by Suzanne de la Monte, refers to the condition when brain tissue becomes resistant to insulin. This is similar to Type 2 diabetes, but the brain is injured.

Here’s the proposed toxic cycle. A high-sugar high-fat diet leads to higher levels of insulin in the brain. The high levels of insulin block the enzyme that normally eats the beta amyloid protein. It is this amyloid protein that leads to plaque buildup which is one of the symptoms of Alzheimer’s disease. These beta amyloid proteins amass in toxic quantities. Neurons become resistant to the effects of insulin. Beta amyloid protein blocks insulin receptors on neurons. The neurons make greater quantities of beta amyloid protein. Eventually insulin production becomes exhausted and drops off This leads to brain damage and dementia. Now insulin can offset beta amyloid damage by blocking its landing site on neurons. Otherwise the cell is more vulnerable to damage.

According to the New Scientist article, a variety of animal studies have supported this explanation. The article also cites two studies involving humans. One of them involves human cadavers. Steven Arnold of the University of Pennsylvania bathed various tissue samples in insulin to see how they would react. Neurons from cadavers of those who had had Alzheimer’s barely reacted at all, but the neurons from cadavers who had not had Alzheimer’s seemed to spring back to life.

Research with living humans is investigating whether a boost of insulin might improve symptoms of those with Alzheimer’s. They used a device that delivers insulin deep into the nose, where it then travels to the brain. A four month study involving 104 people found that the treatment resulted in the recall of more details of stories, longer attention spans, more interest in their hobbies and being better able to care for themselves. The treatment also improved the glucose metabolism in their brains.

There is ample evidence that a healthy diet fosters a healthy memory. However, it should be remembered that although amyloid plaque might be a necessary condition for Alzheimer’s, it is not a sufficient condition. There have been autopsies of people whose brain’s were in sad shape due to the buildup of amyloid plaque, but who had not exhibited any symptoms of Alzheimer’s while they were alive. So the buildup of a cognitive reserve through healthy cognitive activities throughout one’s lifetime is quite important. One of the primary goals of the healthymemory blog is to provide guidance on these healthy cognitive activities.

1Trivedi, B. (2012). Eat Your Way to Dementia, New Scientist, 1 September, 32-37.

© Douglas Griffith and healthymemory.wordpress.com, 2012. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

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