Normal Test Results Aren't the Same as Optimal — Especially for Your Brain
How to Read Your Standard Lab Tests Through the Lens of Alzheimer's Prevention
By the time I had the opportunity to test my mother, she had Alzheimer’s. Her lab results revealed a great deal about the metabolic road that had brought her there.
Her fasting glucose was 102. Technically just over the line into prediabetic range, the kind of number a doctor might mention briefly and suggest she watch her diet. Nothing urgent. Except it is.
Her triglycerides were 436. That’s not a subtle signal. It’s safe to assume it had been high for a long time. That’s a system in serious metabolic distress — the result of a diet high in carbohydrates and sugar, and a clear sign of the insulin resistance that diet had produced. High triglycerides interfere with the brain's ability to use glucose efficiently — which matters enormously for a brain already at risk for the energy deficits that drive Alzheimer's disease. Her mother, grandmother, and sister had all had the disease.
Her hs-CRP — a marker of systemic inflammation — was 3.16. Anything above 1.0 is considered elevated from a cardiovascular standpoint. Hers was more than three times that.
Her fasting insulin was 11.7. This is not a standard test — her doctor almost certainly never ran it. Combined with her fasting glucose of 102, that tells you her cells were already experiencing insulin resistance.
Her A1c was 5.4. Completely normal — and almost certainly the number that would have reassured everyone. But a normal A1c alongside elevated insulin isn’t a clean result. It means her pancreas was still working hard enough to keep blood sugar out of the diabetic diagnosis range, while the underlying system was already under serious strain.
Her HDL was low at 51. That means her triglyceride/HDL ratio was 8.5:1. That’s a powerful warning sign for insulin resistance—her cells had stopped responding normally to insulin, and her body had likely been compensating for years without any obvious symptoms.
This is the metabolic environment that should concern everyone related to their risk for Alzheimer’s.
Glucose, triglycerides, insulin, inflammation. These numbers told a metabolic story that had been shifting for years — within ranges that attracted no medical attention, while the disease was already well underway. We know Alzheimer’s begins a couple of decades before symptoms.
Her maternal history made it all track. Raising the very real issue of brain hypometabolism that you can read about by clicking this link. But her doctor may not have known about her maternal history of Alzheimer’s, or how these markers further elevated her risk.
Even today, Alzheimer’s prevention isn’t the lens through which traditional doctors are viewing lab results.
These aren’t obscure markers. With the exception of fasting insulin — and usually A1c — they appear on the standard blood work your doctor orders every year.
Which means you can start using them to protect your metabolic health, whether your doctor flags them or not. The most powerful tools for protecting your brain aren’t prescriptions or procedures — they’re diet, movement, sleep, and targeted supplementation.
Things you control entirely on your own.
If fasting insulin isn’t already on your panel, ask your doctor to add it next time. Once you have both glucose and insulin results, you can calculate your HOMA-IR — a measure of insulin resistance — using a free online calculator.
A score below 1.0 is optimal. Above 1.9 suggests early insulin resistance is developing. Above 2.9 indicates it is already significant. My mom’s was 2.9.
Insulin resistance is so consistently linked to Alzheimer’s disease that some researchers have called it Type 3 diabetes. These are not numbers to leave unexamined. And this is not the only contributor.
Brain hypometabolism is when the brain’s ability to use glucose is impaired; an early risk factor for Alzheimer’s that begins decades before symptoms, especially if you have a maternal history of the disease.
Insulin and glucose have a close relationship in the body and the brain. Take these numbers seriously, along with your triglycerides. These are easy first steps for your Alzheimer’s prevention strategy. They aren’t the only ones, but they are important.
You actually have a lot of control over preventing Alzheimer’s – this is just the tip of the iceberg. But getting your metabolic health under control is foundational.
What follows for premium subscribers are the optimal ranges for several key markers found on standard lab panels you probably have results for — what to look for, what warrants attention, and what you can start doing about it today.