Fasting Glucose (Mg/Dl) x Fasting Insulin /
405
While reference values generally state that any figure under
2 is normal, lower is better and an optimal HOMA-IR is
under 1. Anything over 2.75 is considered insulin resistant.
The research clearly indicates that higher HOMA-IR values
are associated with worse cognitive performance in the
present as well as in the future.
Insulin resistance is also extraordinarily common in
people with Alzheimer’s disease: 80 percent of people with
the disease have insulin resistance, which may or may not
accompany full-blown type 2 diabetes.^19 Observational
studies have shown that having type 2 diabetes equates to a
two- to fourfold increased risk of developing Alzheimer’s
disease. All told, 40 percent of Alzheimer’s cases may be
attributable to hyperinsulinemia alone, and a growing
chorus of researchers and clinicians are now referring to
Alzheimer’s as “type 3 diabetes.” To be sure, type 2
diabetes doesn’t cause Alzheimer’s disease—if it did,
everyone with type 2 diabetes would develop Alzheimer’s
and everyone with Alzheimer’s would be diabetic, neither of
which is the case. It does, however, seem increasingly clear
that the two are inbred cousins of each other.
The takeaway here is that even below the level of
diabetes, or even prediabetes, chronically elevated insulin
may be wreaking havoc, impairing the performance of your
brain while setting the stage for widespread neuronal
dysfunction decades in the future.