Understanding the link between Diabetes & Alzheimer's disease
By Gordon Cohen, MD, PhD
Most of us are familiar with two types of diabetes: type 1 (juvenile onset) and type 2 (adult or acquired) diabetes. Diabetes is a problem with blood sugar regulation in the body that can lead to more serious health concerns. More recently, a third type of diabetes, which has been linked to Alzheimer's disease has come to light. To understand this better, let's first look at the most common form of diabetes, type 2.
The link between type 2 diabetes & Alzheimer's disease
The exact connection between Alzheimer's disease and type 2 diabetes is still unknown. However, poorly controlled blood sugar may increase the risk of developing Alzheimer's. In fact, this relationship is so strong that some have called Alzheimer's "diabetes of the brain" or "type 3 diabetes."
A recent study presented at the Society of Neuroscience suggests that Alzheimer's may actually be the late stage of type 2 diabetes. The study, which was conducted at University of Albany, suggests that the excess insulin produced due to insulin resistance can actually cross into the brain and disrupt brain chemistry, which leads to the production of toxic proteins that "poison" brain cells. The amyloid protein that forms in both Alzheimer's patients and those who have type 2 diabetes is identical. Dr. Ewan McNay, a lead researcher at the University of Albany, said, "People who develop diabetes have to realize this is more than controlling their weight or diet. It's also the first step on the road to cognitive decline. At first they won't be able to keep up with their kids playing games, but in 30 years' time they may not even recognize them."
Over the past decade as the connection between type 2 diabetes and Alzheimer's has become stronger, so have the studies supporting such a concept. For example, people who develop type 2 diabetes usually develop some sort of change in their cognitive function, but most strikingly nearly 70 percent of them ultimately develop Alzheimer's. Another study found that people with type 2 diabetes were more likely to develop brain "tangles" commonly seen in people with Alzheimer's disease, even if they didn't have dementia or memory loss.
Type 2 Diabetes
One of the key features of type 2 diabetes in insulin resistance. Insulin, a hormone produced by your pancreas, works to drive sugar into the cell that is used for energy production. Your body normally maintains a constant level of glucose in the blood stream that's tightly regulated. Insulin resistance, the inability of your body to respond or use insulin appropriately, occurs when the pancreas can't make enough hormone to keep up. When this happens, blood glucose levels rise above normal and you become hyperglycemic. It's unknown why this happens, although genetics and environmental factors, such as excess weight and inactivity, seem to contribute.
Type 2 diabetes can be easy to ignore, especially in the early stages when you're feeling fine. But diabetes affects major organs including your heart, blood vessels, nerves, eyes and kidneys. Controlling your blood sugar levels can help prevent complications including:
- Heart attack, stroke and other organ problems due to atherosclerosis (narrowing) of the arteries, especially in combination with hypertension
- Neuropath (nerve damage). Too much sugar results in injury to the walls of the capillaries. This can be especially true in the legs where tingling, numbness, burning or pain begin at the tips of the toes (or fingers) and gradually spreads upward. Poorly controlled blood sugar can eventually cause you to lose all sense of feeling in the affected limbs. Lower limb amputations are not uncommon in severe type 2 diabetics due to non-healing and infected wounds. Also damage to the nerves that control digestion can cause problems with nausea, vomiting, diarrhea or constipation
- Nephropathy (kidney damage). Chronic or even severe damage can lead to kidney failure or irreversable end-stage kidney disease, which typically results in dialysis or a kidney transplant
- Diabetic retinopathy (eye damage) can progress to the point of total blindness or an increased risk of other serious eye conditions, such as cataracts and glaucoma
- Hearing impairment, skin conditions or erectile dysfunction (in men)
What you can do to prevent Alzheimer's
It's quite clear that making lifestyle changes such as regular exercise, maintaining a healthy body weight and percentage of body fat, eating healthy foods, managing your cholesterol, managing blood pressure and not smoking can make a huge impact in your health and reducing the risk of type 2 diabetes. If you need help getting started, the 20/20 LifeStyles program can help you meet these challenges head on.