Diabetes and Alzheimer's Disease: What's the Connection?
Does your memory seem to be getting worse? Better check your blood sugar! Recent scientific findings indicate that poor blood sugar control may be detrimental for memory.
In fact, statistics tell us that your risk of developing Alzheimer's disease is substantially increased—not only if you have diabetes (type II), but also if you have impaired glucose tolerance, a condition that precedes the onset of diabetes. Unfortunately, the simple but essential test needed to detect this pre-diabetic condition, an oral glucose tolerance test, is rarely performed in the course of a typical annual physical. As a consequence, many older adults are unaware that they are at an increased risk of developing more serious memory problems down the road. This is unfortunate because if you knew you had impaired glucose tolerance, you could make a few simple but critical lifestyle changes and potentially correct the problem.
Glucose (sugar) is the fuel that makes the heart tick, the leg muscles contract, and the brain function. Shortly after we eat a meal, blood sugar levels rise, and in response, the pancreas releases insulin. Insulin must be available if glucose is to be relocated from the bloodstream to the various body tissues for fuel.
For some, blood sugar levels remain elevated for long periods of time. As a consequence, the pancreas works overtime and insulin levels skyrocket. Eventually, insulin loses its potency to do its job with the same efficiency. (This change in potency is similar to that observed for certain medications, when a person builds up a tolerance and ultimately more medication is needed to get the same effect.) So, when the body becomes less responsive to insulin, or "insulin resistant," it can no longer efficiently use glucose (glucose intolerance) and the brain is now at risk of getting a reduced supply of fuel, and can no longer reap other benefits of normal insulin action. Over the long run, these changes will take a toll on memory.
Many people with memory problems, including those with Alzheimer's disease, have insulin resistance and impaired glucose tolerance—conditions that once were associated only with diabetes. One way to treat or prevent diabetes is to increase the body's sensitivity to insulin so that glucose can be used more efficiently. One of the most effective ways to increase insulin sensitivity is to exercise! When your muscles are working, they require more fuel. More demand by your muscles depletes the blood supply of glucose. When the blood supply is depleted, less insulin is produced by the pancreas. When less insulin is produced, the body becomes more sensitive to insulin (less supply, more demand).
A second effective way to increase insulin sensitivity is through diet. Diets high in saturated fats and high in sugar lead to high glucose levels in the blood for extended periods of time. As a consequence, insulin levels are also elevated in the bloodstream for longer periods of time.
The Memory Wellness Program of the University of Washington and the VA Medical Center is studying the link between memory and energy metabolism (glucose and insulin release) for older adults in the Puget Sound region in hopes of preventing or delaying the onset of Alzheimer's disease. Prevention of Alzheimer's disease through improving the body's use of its own insulin and glucose may sound too simplistic or even unobtainable, but for Alzheimer's patients and their families it means hope.
The research of Dr. Suzanne Craft and the Memory Wellness Program was recently featured in the HBO Special: "The Alzheimer's Project." In the "Science and Medicine" segment of this award winning production, Dr. Craft talks more about this important connection between insulin, glucose and memory, and the role of impaired insulin action on the development of Alzheimer's disease. You can visit the HBO "The Alzheimer's Project" webpage to view the entire series and learn more about this timely new area of research.
Research efforts are only made possible through the participation of our dedicated study volunteers. If you, a family member or loved one are concerned about changes in memory and are interested in finding out more about participating in one of the studies conducted by the Memory Wellness Program and supported by the National Institutes of Health, please contact Julie Moorer, R.N., Director of Recruitment, UW/VA Memory Wellness Program, 1-866-638-8813 (toll free) or visit the Memory Wellness Program website.