Sweet Way to Prevent Memory Loss: Cut the Sugar

If you want to stay sharp well into your golden years, put down that doughnut and hit the treadmill, says a recent study published by Columbia researchers.

Columbia University Medical Center's Scott Small, an assistant professor of neurology, led a multi-institutional team of researchers in a study designed to investigate the precise cause of the memory deficits that seem to become more common as people age. They discovered that poor blood sugar control, common in older people, can damage the hippocampus, a critical region of the brain that is heavily involved in forming and recalling memories. The findings suggest that better control of blood sugar might help to stave off memory problems.

Researchers have discovered that damage to the hippocampus is involved in age-associated memory loss. But since older people face a variety of health problems, scientists had trouble isolating the precise causes of "senior moments."

The researchers began by using an fMRI machine to peer into the brains of 240 human subjects, zooming in on the hippocampus in such detail that they were able to identify four specific parts of the region. They noticed that damage to the dentate gyrus, a part of the hippocampus, was much more common among those with high blood sugar and diabetes than in subjects with normal blood sugar. This sort of brain injury is associated with poor performance on memory tests.

Still, the results may not be conclusive, since the interaction between diabetes and other diseases common in elderly patients—especially Alzhiemer's—can make it hard for scientists to pin down what really causes memory loss.

To strengthen their conclusion, the researchers studied the brains of rhesus monkeys and mice. These animals do not suffer from Alzheimer's disease, so scientists could be sure that any brain damage was the result of high blood sugar levels. In both animals, the team found the same correlation between high blood sugar and damage to the dentate gyrus, confirming their hypothesis.

The study has important implications for the treatment of diabetes patients, who are already at high risk of high blood sugar and therefore brain damage. However, even people who do not have diabetes frequently experience poor sugar control as part of the aging process.

"Whether through physical exercise, diet or drugs," Small said in a press release, "our research suggests that improving glucose metabolism could help some of us avert the cognitive slide that occurs in many of us as we age."