Diabetes and Alzheimer’s disease are so closely linked—in causes, in risk factors, even in some of their effects and symptoms—that Alzheimer’s has been referred to as "type 3 diabetes." Uncontrolled diabetes is very closely associated with a heightened risk of developing vascular dementia resulting from poor blood flow to the brain, in old age. Worse, some researchers suspect there’s a cycle, with diabetes and dementia each making the other worse.
Moreover, new research suggests that you don’t have to have diabetes, or even a diabetes precursor, such as glucose intolerance, for your memory to be affected. A recent study found that simple high blood sugar is enough to affect subjects’ performance on a standard laboratory memory test. The subjects all had blood sugar near the top of the normal range, well below the level that is the standard for a diagnosis of diabetes. In addition to the memory test, brain MRI scans showed that the area of the brain responsible for memory was lower in people with high blood sugar levels.
"These results suggest that even for people within the normal range of blood sugar, lowering their blood sugar levels could be a promising strategy for preventing memory problems and cognitive decline as they age," said Dr. Agnes Floël, the author of the study, in a statement. "Strategies such as lowering calorie intake and increasing physical activity should be tested."
In addition to keeping blood sugar levels under control, there are several things you can do to help maintain and improve your memory. For one thing, in addition to physical activity, make sure to keep up mental activity. Don’t let yourself stagnate alone; things like crossword puzzles, spending time with friends or in group activities, or learning a language or a musical instrument can all help keep your mind sharp. You’re never too old to take a class or learn a craft. Keeping your space organized will help organize your brain, and make it easier to remember things in general. Preventing dementia won’t just give you a longer life, but also a richer one; it means having not just more years, but better years.