New research shows that the brain’s ability to process glucose is linked with amyloid plaques and tau tangles, biomarkers of Alzheimer’s.
A new study by the National Institute on Aging, part of the National Institutes of Health, has linked how efficiently the brain breaks down glucose with Alzheimer’s disease.
The study showed that how the brain processes sugar related not only to the amount of protein plaques present, but also the severity of Alzheimer’s and memory loss.
The brain uses glucose, a form of sugar, to fuel processes like thinking, memory and learning. The brain requires glucose to function; it’s the most energy-demanding organ and uses up half of the available glucose energy in the body. But too much of it can be a bad thing, and glucose in excess has been linked to problems with memory and can speed up the aging of cells.
In the study, people whose brains were bad at breaking down glucose had more beta amyloid protein plaques and tau tangles in their brains compared to those who broke down glucose normally. Plaques and tangles are the hallmarks of Alzheimer’s disease. Researchers looked at brain samples collected from autopsies by the Baltimore Longitudinal study on Aging, a research project which tracks the neurological, physical and psychological data of participants over several decades. The study looked at those with a confirmed Alzheimer’s diagnosis, a healthy control group and those with the pathology of Alzheimer’s, but no symptoms.
By analyzing the data, scientists were able to confirm that those with lower levels of the enzyme required to break down glucose had a higher instance of Alzheimer’s diagnosis during their lifetime. Brains that had very high levels of glucose were more likely to have the symptoms of Alzheimer’s along with the pathology in the brain. They also found that those with higher levels of blood sugar in the years before death had greater levels of glucose in the brain when they died.
However, the study did not examine whether consuming a lot of sugar might lead to Alzheimer’s for those who had trouble processing glucose.
“In terms of our findings, there really is no direct implications as far as risk or being able to lower your chances of getting Alzheimer’s,” said Madhav Thambisetty, M.D., Ph.D., investigator and chief of the Unit of Clinical and Translational Neuroscience in the NIA’s Laboratory of Behavioral Neuroscience. “It wasn’t a question we addressed.”
However, Thambisetty points out that past studies have found a link between diabetes, which increases the amount of sugar in blood, and dementia. Experts say risk of dementia goes up 75 to 100 percent when diabetes is also a factor.
“I think the next steps for us are to find out what triggers these abnormalities,” said Thambisetty. “It’s exciting that we can find abnormalities that are linked [to the pathology of Alzheimer’s], but this opens up finding the cause. Once we do that, we’re a step closer to asking how can we prescribe lifestyle and diet alterations,” he said.
Read the full write-up of the study, which was published in Alzheimer’s & Dementia: the Journal of the Alzheimer’s Association, here.
—by Emily Woodruff