High but normal blood sugar levels affect brain health
Blood sugar levels consistently at the high end of the normal range in individuals without diabetes caused brain changes associated with dementia, a 2012 study showed. Loss in brain function is found in dementia-related diseases such as Alzheimer's, CBS News noted.
Those alterations included shrinkage of two parts of the brain involved in cognitive function and memory -- the hippocampus and amygdala, CBS News reported. Researchers found blood sugar to be responsible for 6 percent to 10 percent of the size reductions, after factoring in other potential causes, including alcohol consumption, smoking, age and high blood pressure.
"These findings suggest that even for people who do not have diabetes, blood sugar levels could have an impact on brain health," said Dr. Nicolas Cherbuin, study researcher at the Australian National University.
Cherbuin described the link between high normal blood sugar levels and brain shrinkage as "robust," according to WebMD. He next plans to investigate the effects seen in this study.
Published in the Sept. 4 issue of Neurology, the study assessed 266 people between ages 60 and 64, with blood sugar in the normal range of below 110 mg/dL while fasting. (A fasting blood sugar level of 180 mg/dL indicates a person has diabetes; a 110 mg/dL level means a person has pre-diabetes.) Researchers scanned the participants' brains at the start and again about four years later.
According to The Huffington Post, another recent study conducted by New York University School of Medicine researchers and published in Pediatrics, found teens with metabolic syndrome -- a component of which is insulin resistance characteristic of pre-diabetes -- had decreased volume of the hippocampus.
Dr. Marc Gordon, chief of neurology at Zucker Hillside Hospital in Glen Oaks, N.Y., told WebMD based on Cherbuin's study, a re-evaluation of what constitutes normal blood sugar levels is warranted and further study is needed.
"The research is too preliminary, and the association shown here does not establish a cause or mechanism," he said.
Cherbuin said all that's involved in regulating blood sugar remains unknown. What's clear, however, is poor nutrition, lack of exercise and ongoing stress likely contribute to high, unhealthy levels.
"Blood Sugar Levels On High End Of Normal Tied To Brain Shrinkage: Study," HuffingtonPost.com, September 6, 2012
"Even high normal blood sugar levels may induce brain shrinkage," CBSNews.com, September 4, 2012, Michelle Castillo
"Normal Blood Sugar Levels May Harm the Brain," WebMD, September 4, 2012, Matt McMillen