Low Blood Sugar Levels May Keep Alzheimer's At Bay

People with diabetes are more likely to develop Alzheimer's disease. Researchers say they are beginning to understand why, and the answer has to do with the way the brain uses sugar.

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Brain scientists say there is a new reason to keep your blood sugar levels under control. Doing so might help lower your risk for Alzheimer's disease. NPR's Jon Hamilton reports from the Society for Neuroscience meeting in Chicago.

JON HAMILTON, BYLINE: Scientists know there's some kind of link between Alzheimer's and diabetes. Dr. David Holtzman is a neurologist at Washington University in St. Louis.

DAVID HOLTZMAN: The risk for dementia is elevated about twofold in people who have diabetes or metabolic syndrome. But what's not been clear is what's the connection?

HAMILTON: At the neuroscience meeting yesterday, Holtzman moderated a panel featuring researchers trying to answer that question. Liqin Zhao of the University of Kansas talked about how brain cells turn sugar into energy. She says one part of that process is called glycolysis.

LIQIN ZHAO: Glycolysis actually supports multiple functions in the brain in addition to energy production, which is pretty obvious.

HAMILTON: Zhao says glycolysis helps brain cells communicate and get rid of the toxins associated with Alzheimer's. So she gave mice a substance that she thought might help. It's found in the brains of people with a gene that protects them against Alzheimer's. And sure enough, Zhao says, the substance made brain cells healthier overall.

ZHAO: All of this together increased the brain's resilience against the onset of Alzheimer's disease.

HAMILTON: Another researcher talked about how blood sugar might be contributing to the sleep problems that often affect Alzheimer's patients. Shannon Macauley from Wake Forest School of Medicine says studies of mice found that the brain changes associated with Alzheimer's can interfere with sleep. But, she says, so can abnormal levels of blood sugar.

SHANNON MACAULEY: Whether your blood sugar is high or low, which are both found in diseases like Type 2 diabetes - that this can actually lead to disrupted sleep.

HAMILTON: Macauley says restoring normal levels of blood sugar in Alzheimer's patients could improve their sleep and might even slow down the disease. David Holtzman says this sort of research on animals should eventually help people.

HOLTZMAN: If we can figure out what diabetes is doing to increase risk, maybe that would lead us to new targets - drug targets or treatment targets.

HAMILTON: In the meantime, Holtzman says, people worried about Alzheimer's might want to keep an eye on their blood sugar.

HOLTZMAN: There's many reasons to get it back under control, but this is certainly one of the reasons.

HAMILTON: Jon Hamilton, NPR News, Chicago.

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