Blood Sugar and Brain Shrinkage: Normal Blood Sugar Leading to Dementia, Alzheimer's?

A new study has revealed that higher levels of blood sugar over a long period of time could be linked to brain shrinkage and as a result, dementia.

While it has previously been stated that high blood sugar levels can contribute to dementia, it was not clear before which levels of blood sugar posed a risk. But according to the latest study, even blood sugar levels at the higher range of "normal" can pose a danger.

"Numerous studies have shown a link between type 2 diabetes and brain shrinkage and dementia, but we haven't known much about whether people with blood sugar on the high end of normal experience these same effects," study author Dr. Nicolas Cherbuin, chief investigator at the Eccles Institute of Neuroscience at Australian National University in Canberra, said in a press release.

Over 300 million people worldwide have been diagnosed with diabetes, according to the World Health Organization. Of those people, 90 percent suffer from type-2 diabetes, which occurs when a person's body is not using insulin effectively.

In the most recent study, published in the Sept. 4 print issue of Neurology, 266 people between the ages of 60-64 were evaluated. The results revealed that those who fell within the normal range of blood sugar, but neared 6.1 mmol/l (the maximum range within normal) suffered from significantly more brain loss in the hippocampus and the amygdala than those who had lower blood sugar levels.

Those areas of the brain affect memory and cognitive skills and have been associated with dementia diseases, included Alzheimer's.

"These findings suggest that even for people who do not have diabetes, blood sugar levels could have an impact on brain health," Cherbuin said. "More research is needed, but these findings may lead us to re-evaluate the concept of normal blood sugar levels and the definition of diabetes."