Scientists have long known that there is a strong association between diabetes and Alzheimer's, but the nature of that relationship - and how to treat it - was unclear. Now Melissa Schilling, an innovation professor at NYU, has discovered the pathway between diabetes and Alzheimer's, and it has big implications for how Alzheimer's can be prevented.
Professor Schilling compared and integrated decades of research on diabetes, Alzheimer's, and molecular chemistry, focusing in particular on results that seemed to yield conflicting results. It turns out that routine practices in research - like excluding all patients with known medical problems such as diabetes from an Alzheimer's study, for example - had obscured the mechanisms that connect the two diseases. Those main mechanisms turn out to be insulin and the enzymes that break it down. The same enzymes that break down insulin also break down amyloid-beta, the protein that forms tangles and plaques in the brains of people with Alzheimer's. When people have hyperinsulinemia (i.e., they secrete too much insulin due to a poor diet, pre-diabetes, early diabetes, obesity, etc.) the enzymes are too busy breaking down insulin to break down amyloid-beta, causing amyloid-beta to accumulate.
The American Diabetes Association estimates that roughly 8.1 million Americans have undiagnosed diabetes and 86 million have pre-diabetes and have no idea. The good news is that hyperinsulinemia is preventable and treatable through changes in diet, exercise, and medication. Schilling notes, "If we can raise awareness and get more people tested and treated for hyperinsulinemia, we could significantly reduce the incidence of Alzheimer's disease, as well as other diabetes-related health problems. Everyone should be tested, early and often, preferably with the A1C test that doesn't require fasting. Dementia patients should especially be tested - some studies have shown that treating the underlying hyperinsulinemia can slow or even reverse Alzheimer's."
Professor Schilling's research has been published in Journal of Alzheimer's Disease.