“Individuals with normal fasting blood glucose may indeed be quite comfortable that they are nondiabetic—that is until they have their first heart attack. […] Those with cardiovascular disease not identified with diabetes are simply undiagnosed.”

-Joseph Kraft MD Diabetes Epidemic & You 

Those are quite bold statements but a mounting body of evidence suggests they may be true. It’s no secret that hyperinsulinemia and insulin resistance underlie a vast array of chronic health conditions affecting everything from reproductive health to cardiovascular disease and “idiopathic” issues such as vertigo tinnitus and ”essential hypertension.” Unfortunately thousands—potentially millions—of individuals with chronic hyperinsulinemia will remain unaware that the primary cause of their intractable health conditions is this underlying metabolic disturbance. As a result they may spend decades being treated with pharmaceutical drugs and other interventions that are completely ineffectual for improving their health because they are aimed solely at ameliorating symptoms rather than addressing the root cause.

 The reason these people will be missed is because the current paradigm for assessing risk for diabetes is based almost exclusively on glucose dynamics. The criteria for being diagnosed with type-2 diabetes (T2D) is limited to an elevated fasting blood glucose (FBG) elevated hemoglobin A1c and/or an abnormal response to an oral glucose tolerance test (OGTT). And while hyperglycemia is certainly a marker for compromised metabolic health even those with normal FBG A1c and response to an OGTT are not necessarily “in the clear” with regard to carbohydrate metabolism and fuel partitioning in the body.

 According to Joseph Kraft MD author of the book Diabetes Epidemic & You: 

“The pathology of diabetes mellitus occurs in those with normal blood sugars. There are far too many who are told ‘Don’t worry your fasting blood sugars are normal.’” “Normal weight normal BMI normal fasting blood sugar and normal fasting insulins do not exclude hyperinsulinemia type 2 diabetes.”

Dr. Kraft who served for 35 years as Chairman Department of Clinical Pathology and Nuclear Medicine St. Joseph’s Hospital Chicago performed tens of thousands of OGTTs over a period of several years and his findings were astounding. Unlike the traditional 2-hour OGTT Kraft performed a 5-hour test including insulin assays. This allowed him to see physiological effects that were missed by tests that ran only two hours and did not include insulin assays. What Kraft’s tests revealed was that thousands of people with normal FBG normal A1c and even normal responses to the traditional 2-hour OGTT had these “normal” results due to hyperinsulinemia. That is the blood glucose was not elevated but the reason it was not elevated is because it was being “kept in check” by very high insulin levels—which are problematic on their own regardless of what happens with glucose.

Kraft observed these patterns over and over again. He called the phenomenon “occult diabetes” or “diabetes in-situ” and he believed people with severe hyperinsulinemia were essentially diabetic; all that was missing for an official diagnosis was elevated glucose. By focusing solely on glucose and not measuring insulin dynamics physicians—and their patients—remain unaware that chronically elevated insulin may be the driving factor behind the compromised health that reduces millions of people’s quality of life so dramatically. This may be particularly true of conditions that are otherwise “idiopathic” and notoriously difficult to treat such as Ménière's disease and other unexplained cochleovestibular disorders.

There are of course many indirect or proxy indicators of hyperinsulinemia/insulin resistance. Among these are low HDL large waist circumference hypertension elevated triglycerides elevated uric acid and more. However despite having some of these markers many patients may be told that they are not diabetic simply because their blood glucose is normal. They may receive advice to “watch and wait” rather than being advised to lower their carbohydrate intake get more sleep exercise and engage in other diet and lifestyle interventions that may help reduce insulin resistance.

Patients who are known to have unhealthy diets and habits but who appear—on the outside anyway—to be healthy and who may even have “normal” blood glucose may in fact have very dangerous metabolic changes brewing inside and the single-minded focus on glucose when screening for diabetes has the potential to lull people into a false sense of security regarding their health. 

Fortunately a growing number of physicians and laboratories are becoming aware of the limitations of measuring glucose when assessing risk for T2D and diabetic complications. Many health conditions typically associated with T2D might leave physicians and patients baffled when blood sugars appear completely normal. Broadening the view to include direct measurements of insulin via an extended OGTT with insulin assay may help identify those at risk for severe health complications and may also help guide treatment strategies.