High Blood Sugar Levels Linked to Brain Decay

We all know sugar is bad for our teeth, but studies find it is also bad for our learning and memory.

Otherwise healthy people with high blood sugar levels are more likely to have memory problems, according to a recent study published in the journal Neurology.

The study was careful to recruit people without diabetes, glucose intolerance or chronically high blood sugar levels (Kerti et al., 2013).

Also excluded from the 141 participants, whose average age was 63, were people who were overweight or had a drink problem.

The researchers carried out both a memory test and scanned participants’ brains, concentrating on the size of the hippocampus, a structure vital for memory.

The main memory test involved people learning a list of words, then trying to recall them 30 minutes later.

The results showed that the lower people’s blood sugar levels, the more words they could remember.

Along with a better memory, those with lower blood sugar levels also had larger hippocampi, suggesting their memory was in better shape.

One of the study’s authors, Dr. Agnes Flöel, said:

“These results suggest that even for people within the normal range of blood sugar, lowering their blood sugar levels could be a promising strategy for preventing memory problems and cognitive decline as they age. Strategies such as lowering calorie intake and increasing physical activity should be tested.”

Brain decay

This is not the first study to link higher levels of blood glucose with smaller brain structures, particularly the hippocampus.

Studies of those with type 2 diabetes and those with problems absorbing glucose have linked it with higher rates of Alzheimer’s and dementia.

The authors suggest sugar may have a toxic effect on the brain, particularly in its memory centres:

“Direct “toxic” effects of glucose on neuronal structures include disturbances of intracellular second messenger pathways, imbalance in the generation and scavenging of reactive oxygen species, or advanced glycation of important functional and structural proteins in the brain. […] Because of its high vulnerability, the hippocampus may be one of the first targets of the deleterious processes set in motion by chronically elevated glucose levels.”

Image credit: Jeanny