MONDAY, Feb. 3, 2003 (HealthDayNews) -- When your blood sugar levels rise to abnormal levels, you're not just courting diabetes, a new study suggests. Your memory may suffer and your brain may actually shrink.
The research gives sedentary, fast food-loving Americans yet another reason to get off the couch and eat more healthfully, says lead author Dr. Antonio Convit, medical director for the Center for Brain Health at the New York University School of Medicine. Those who exercise regularly and eat well generally have healthier blood sugar levels.
The research appears this week in the Proceedings of the National Academy of Sciences.
In the study, Convit and his colleagues evaluated 30 adults, ages 53 to 89, none of whom were diabetic but some of whom had a condition called impaired glucose tolerance, or prediabetes, in which blood sugar levels are higher than normal.
The adults all received glucose intravenously and the researchers measured how quickly the sugar moved to the tissue, an indication of their glucose tolerance. Then they tested the subjects' ability to recall short paragraphs and do other cognitive function tests. They also did brain scans with magnetic resonance imaging, or MRIs.
Those with the lowest scores on the mental tests had the poorest glucose tolerance. They also had a smaller hippocampus, a key area in the brain for learning and recent memory, such as remembering later in the day what you ate for breakfast. What might be happening, the researchers suggest, is that the inability of the hippocampus to absorb sufficient glucose for fuel may eventually damage it and cause it to atrophy.
"This study is the first to relate your glucose tolerance -- how well you regulate glucose -- to measurements in your brain," says Convit, who is also a researcher at the Nathan Kline Institute for Psychiatric Research in Orangeburg, N.Y. "It demonstrates an association [but not yet cause and effect] between poor glucose tolerance and memory problems. We've known for years that diabetics have more memory problems than people their own age, even after controlling for cardiovascular disease."
For years, he adds, "we have had hints about people with impaired glucose tolerance also having memory problems. This is an important study because it points out [that] people who are not diabetic, who may just have some mild glucose intolerance, may have memory problems."
About 16 million people between the ages of 40 and 74 in the United States have prediabetes, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
Dr. Francine Kaufman, the president of the American Diabetes Association, calls the new research "obviously intriguing" and agrees with Convit that the findings emphasize the importance of healthful eating and regular exercise.
Adults over age 45 should also ask their primary physician about getting evaluated for glucose tolerance, Kaufman says. Those under age 45 should also ask about a glucose evaluation, she adds, if they are at high risk for developing diabetes. High risk includes, she says, women who have given birth to a child weighing more than nine pounds, and people who are obese, have high blood pressure, have high blood cholesterol or triglycerides, or have blood relatives with diabetes.
"Don't depend on mall screenings for diabetes," Kaufman, a pediatric endocrinologist at Childrens Hospital Los Angeles, warns. "They are often inaccurate." Ask your doctor the best glucose test for you, she suggests.
More information
To find out how to prevent diabetes, go to the National Institute of Diabetes and Digestive and Kidney Diseases. For details on blood glucose tests, see the American Diabetes Association.
