Researchers Link Sugar and Memory

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.

Scott Small, an assistant professor of neurology at the Columbia University Medical Center, 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 may allow doctors to develop better tests for Alzheimer’s disease, and suggest that better control of blood sugar might help to stave off memory problems.

Researchers have found that damage to the hippocampus is involved in age-associated memory loss. Since older people face a variety of health problems, scientists formerly had trouble isolating the precise causes of “senior moments.”

Small’s team began by using an fMRI machine to peer into the brains of 240 human subjects, zooming in on the hippocampus and identifying four specific parts of the region. They found that damage to the dentate gyrus was much more common among the people with high blood sugar than among those with normal blood sugar. This sort of brain injury is linked to poor performance on memory tests.

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

To strengthen their theory, the researchers studied the brains of rhesus monkeys and mice. These animals do not suffer from Alzheimer’s, 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.

One important result of the study concerns the detection of Alzheimer’s. Currently, the illness’ diagnosis is more an art than a science, since the devastating plaques that characterize the disease can be seen only after performing an autopsy. Doctors find that the early stages of the illness can be especially tricky to distinguish from others.

But now that Small’s team has shown that different diseases affect different parts of the hippocampus, it may be possible to develop a more definitive and non-invasive diagnostic procedure. This achievement could make a big difference for patients, since the drugs used to slow the inevitable mental decline associated with Alzheimer’s work best when used during the disease’s early stages.

Small said he hopes that patients worried about the early signs of Alzheimer’s may soon have a new option. “In the future, if we validate this technique, we can take that person and give them a high-resolution fMRI,” he said.

The study has important implications for the treatment of diabetes patients, who are already at increased risk of high blood sugar and subsequently brain damage, but 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, 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,” Small said in a press release.

news@columbiaspectator.com