themselves by reducing the availability of receptors to hear
them. In the brain, a reduced ability to “hear” insulin may
negatively affect aspects of your cognition including
executive function and your ability to store memories,
focus, feel a sense of reward, and enjoy a positive mood.
It’s no secret in the medical literature that having type 2
diabetes can reduce cognitive function, but other research
has shown that even in a nondiabetic person, insulin
resistance is associated with worse executive function and
declarative memory—which is what most of us think of
when we conjure images of a person with a good memory
(and we all want to be that person).^17 One study from the
Medical University of South Carolina that examined the
brainpower of nondiabetic, cognitively “healthy”
individuals found that subjects with higher levels of insulin
not only had worse cognitive performance at baseline (when
the subjects’ labs were first drawn) but exhibited greater
declines on a follow-up six years later.^18
How might you measure your sensitivity (or resistance)
to insulin and, thus, get a handle on your brain
performance? One of the most important numbers to know
is your HOMA-IR. HOMA-IR, which stands for homeostatic
model assessment for insulin resistance, is a simple way of
answering the question How much insulin does my pancreas
need to pump out to keep my fasting blood sugar at its
current level? It can be calculated using two simple tests
that your primary care physician can run: your fasting blood
sugar, and your fasting insulin. The formula to determine
your HOMA-IR is as follows: