Sugar and Alzheimer’s: Is There a Connection?

November 5, 2018

Keeping a lid on treats and desserts is something most of us struggle with to some degree (who among us hasn’t raided their kids’ Halloween candy this time of year?). Staying trim is usually our prime motivator. But new research suggests there may be a much more compelling reason for all of us to curb our sugar intake. While there’s been a lot of attention paid to diet in general and how it relates to dementia, scientists are zeroing in on sugar – namely, high blood sugar levels – as potentially increasing our risk for developing Alzheimer’s disease.

To be clear, this isn’t the first we’ve heard about glucose levels and how they relate to Alzheimer’s. Scientists have long connected Type 2 diabetes with a greater instance of Alzheimer’s, and have looked at the dynamics of blood sugar and insulin as possibly hastening its diagnosis and progress. But several recent studies are starting to connect the dots in new ways among sugary, carb-heavy diets; insulin dependence; and the amyloid plaque build-up that defines Alzheimer’s. Here are some findings to watch:

  • Blood sugar and cognitive decline: As detailed in a recent issue of the journal Diabetologia (, researchers followed over 5000 people for 10 years, tracking their blood sugar and cognitive function. Of the participants, those with (on average) higher blood sugar levels had faster rates of cognitive decline, regardless of whether or not their A1C qualified them as diabetic. Simply put, the higher their sugar intake, the faster their brains showed signs of deterioration.
  • Insulin levels and Alzheimer’s: People with Type 2 diabetes whose bodies can still produce insulin are nearly twice as likely to develop Alzheimer’s. But Type 1 diabetics, who cannot produce insulin, also have an elevated risk of this diagnosis. How can both be right? The answer may lie in how our brains break down and process insulin – through an enzyme that also serves to break down amyloid plaque tangles. New research seems to indicate that Type 2 diabetics, whose insulin levels are frequently depleted by their disease, also lack the proper levels of this enzyme – and therefore aren’t able to break down enough amyloid plaques. And Type 1 diabetics, who inject insulin and often run on a surplus, can sap too much of this enzyme’s attention, thereby seeing amyloid plaques accumulate.
  • High carbohydrate diets and cognitive impairment:  A few interesting findings to explore here. One Mayo Clinic study broke 1,000 people into four groups, corresponding to their carb intake levels. The study subjects who ate the highest amount of carbs were 80 percent more likely to develop mild cognitive impairment (MCI), often a precursor to Alzheimer’s. Johns Hopkins scientists are looking on a cellular level, noting that high sugar intake makes cells insulin-resistant, which can cause them to die off – another connection to brain deterioration.

Lots to follow on the subject; keep it tuned to the Alzheimer’s Association for all the latest info.