A Look at Two Studies Connecting Diabetes & Brain Function

By By Dr. Nadeau

Categories: Diabetes Center
Dr. Nadeau is an accomplished physician who brings extensive experience to the Mary & Dick Allen Diabetes Center as Program Director, Dr. Kris V. Iyer Endowed Chair in Diabetes Care and Endocrinologist at Hoag Medical Group . While he has many areas of interest, the majority of his recent work, research, and lectures focus on diabetes, obesity, and nutrition.

The importance of glucose control has been highlighted in two new studies that look at diabetes and brain function:

Washington University, St. Louis has done studies recently on mice that purposed the idea that "Diabetes may pose a risk for Alzheimer’s." Researchers found that abnormal high levels of blood sugar correlates to an increase in amyloid beta proteins in the brain, which is a risk factor for Alzheimer’s disease. This is important because Type 2 Diabetes (T2D) affects about 29 million people in the U.S. and may lead to other complications such as heart disease, blindness, and death. It is the most common form of diabetes where the body becomes desensitized to insulin. Type 1 Diabetes (T1D) usually starts in childhood as the pancreas does not produce sufficient amount of insulin, a naturally occurring hormone in the body. Both of these types lead to poor sugar metabolism by the cells, which leads to higher than normal blood sugar levels.

Based on a recent study at the University of Pittsburgh, it was found that T1D patients had significantly more brain lesions and slower cognitive function than people without diabetes. There were a total 180 people in this study. One group was comprised of people with T1D with an average age of 50 and another group was non- diabetic patients with an average age of 45. They found that uncontrolled blood sugar has negative clinical effects on the brain over the time, and in some cases even before symptoms of dementia appear. It can affect the speed with which your brain works and how quickly your brain passes information from one part to another part. The lead researcher, Caterina Rosano was surprised because the study participants were so young.

In the Washington University study, the mice’s brains were engineered to resemble an Alzheimer’s patient. As a high dose of sugar was given over a few hours, amyloid beta levels increased in brain cells. However, this can only suggest a relationship between blood sugar levels and amyloid production rather than the development of Alzheimer’s. Similarly, Dr. Holtzman says "high blood sugar appears to affect the way the brain functions." Does this mean insulin may improve brain function such as memory? Dr. Craft’s research suggests improvement in mild memory impairments has been noted with stimulation of insulin production in early Alzheimer’s patient.

Future studies need to be done to conclude such a relationship between diabetes as a risk factor for Alzheimer’s disease.

New technology such as glucose sensors and insulin pumps can dramatically improve glucose in T1D and newer medications have helped revolutionize care in T2D.