Author: Leo E. Hendricks, Ph.D., A.C.S.W., L.I.C.S.W., C.D.E.
As if you don’t already have enough reasons to control your blood sugar, here’s another: preserving your memory. Research has shown that uncontrolled diabetes can lead to mental decline, including memory loss. The recommended steps for preventing such a decline are identical to the steps for preventing most complications of diabetes: Keep blood sugar levels and blood pressure levels as close to normal as possible.
Just about everyone becomes forgetful when they are under stress, tired, ill, distracted, or trying to remember too many things at once. More persistent memory loss and related declines in mental functioning can be caused by alcoholism or drug abuse, drug side effects or interactions, depression, chronic high blood pressure (which often accompanies diabetes), poor nutrition, an underactive thyroid gland, brain and nervous system disorders such as Parkinson disease, a history of transient ischemic attacks (ministrokes), and, of course, Alzheimer disease. Since some of these conditions are reversible or treatable, it’s important to bring symptoms of memory loss or mental confusion to the attention of your doctor.
Diabetes And The Brain
To understand the relationship between diabetes and memory loss, it helps to know a little about how the brain works. The brain’s most important fuel is glucose. The entry of glucose into the brain is regulated at the blood-brain barrier. This barrier, which is formed by the cells that line brain capillaries (very small blood vessels), controls the brain’s environment. It regulates the transport of nutrients into the brain as well as the exit from the brain of chemically charged particles and by-products of brain metabolism.
Although glucose accounts for more than 90% of the metabolic fuel used by the brain, storage of glucose in the brain is very limited. Therefore, a person needs a constant supply of glucose from the blood for normal brain functioning. However, high blood glucose levels do not make the brain function even better: Both extended periods of elevated glucose levels (hyperglycemia) and very low glucose levels (hypoglycemia) are believed to contribute to the development of memory problems in people with diabetes.
High blood sugar is thought to contribute to brain dysfunction by altering cerebral blood flow, affecting brain energy metabolism, and impairing blood-brain barrier function. Its effects may be long-lasting: Many studies suggest that high blood sugar decreases the efficiency with which glucose is transferred from brain capillaries into the brain across the blood-brain barrier. In addition, studies in animals suggest that in the presence of high blood sugar, even a brief reduction in blood flow to the brain is more likely to produce permanent brain injury.