Blood sugar linked to 'senior moments'

The decline in mental sharpness is among the most distressing aspects of aging. But a new study suggests that good blood sugar control, even in people without any evidence of diseases such as diabetes, may be an important strategy to maintain healthy brain function in later life.

The study, published today in the Annals of Neurology, focuses on changes in the hippocampus part of the brain. Even in people without Alzheimer's disease, the hippocampus is vulnerable to aging. As this part of the brain declines, so do functions like memory. Researchers from Columbia University Medical Center, however, have shown that rising levels of blood glucose, which occurs normally during aging, may be a contributing factor to a lackluster function in the hippocampus. Ways to reduce blood sugar levels, such as through exercise, could be a way for people to postpone some of that normal cognitive decline in old age.

"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," said the lead author of the study, Dr. Scott A. Small, in a news release.

To arrive at their findings, Small and his colleagues mapped out specific areas of the hippocampus impacted by diseases such as diabetes and stroke. They found that blood glucose selectively targets the dentate gyrus area of the brain. Decreasing activity in the dentate gyrus correlated with rising blood sugar levels. Other studies have also shown that exercise causes an improvement in the dentate gyrus function.

--Shari Roan

Photo: Cerebral blood flow is mapped in the brain of someone with diabetes. Warmer colors indicate greater activity. Credit: Columbia University Medical Center.

Comments

[Dr. Lee]

But we have to remember that hypoglycemia can also have detrimental effects on the brain.

[Joe]

What I haven't been able to figure out is how high blood sugar has to be to cause these kinds of problems. The study seems to say that even non-diabetic levels are dangerous for memory. But what levels are we talking about. What about a fasting glucose level of, say, 90? Is that dangerous? Or 85? or 100?