The Tip of the Iceberg – what we can’t see puts us at risk

The US and Canada and much of the westernized world is in the midst of a Diabetes epidemic but this is just the tip of the iceberg when it comes the underlying metabolic disruption caused by insulin. The part of the iceberg that is visible and that people know about is hyperglycemia (elevated blood sugar) but the part that is invisible and that few are aware of  hyperinsulinemia (elevated blood insulin levels) which often precedes a diagnosis of pre-diabetes or Type 2 Diabetes by decades. It is this high circulating level of insulin that contributes to the significant risk of developing cardiovascular disease including heart attack and stroke, hypertension (high blood pressure), elevated cholesterol and triglycerides, non-alcoholic fatty liver (NAFLD), Poly Cystic Ovarian Syndrome (PCOS), Alzheimer’s disease and other forms of dementia, as well as certain forms of cancer including breast and colon / bowel cancer.

High blood sugar may or may not be a symptom of high levels of insulin levels and in the early stages of metabolic dysfunction almost 75% of people will have normal fasting blood glucose yet have abnormally high levels of circulating insulin.  As a result, these people are at increased risk of the metabolic diseases mentioned above but unlike someone already diagnosed with Type 2 Diabetes they have no idea!

High circulating levels of insulin is entirely missed by most routine lab tests because blood sugar is being monitored as the first indication that someone is becoming insulin resistant.  By the time blood glucose levels are abnormal, the β-cells of the pancreas that produce insulin are already being over-taxed to the point of exhaustion.  Physicians have “answers” (lab test results) but oftentimes are asking the wrong questions. That is, having normal fasting blood sugar or even HbA1C (3-month blood sugar average) does not necessarily mean everything is “fine”.  Most sobering is that by the time a person is diagnosed with Type 2 Diabetes they have already lost ~ 40% of their beta-cells mass sometimes more – cell loss which is currently thought to be unrecoverable.

The healthy human body maintains blood sugar in a tightly-regulated range between 60-100 mg/dl (3.3-5.5 mmol/L).  When a healthy person eats food containing carbohydrate – whether as the starch in bread, pasta and rice, the sugar in milk (lactose), fruit (fructose), simple table sugar (sucrose) or high fructose corn syrup in commercially prepared foods, special glucose-sensing cells in the small intestine release signalling hormones called incretin hormones in response to the presence of these carbohydrates. The incretin hormones tell the pancreas to release insulin which in turn tells the body’s cells what to do with the energy from the food we eat; either (1) burn it or (2) send it to the liver to store it, first as glycogen, and the remainder as fat (adipose tissue).  This is called fuel partitioning. When metabolic processes respond appropriately, blood sugar rises modestly after eating carbohydrate-based food but is quickly restored to its normal, tightly-regulated range soon afterwards.

Metabolic problems begin because people eat foods that contain some form of carbohydrate every few hours which results in frequent release of insulin. Glycogen levels in the muscle and liver remain close to full due to the steady supply of refined or processed carbohydrate-based food compounded by the reality that body’s cells are rarely challenged to use stored energy. In the early stages cells simply stop responding appropriately to insulin’s signal. This is called insulin resistance. Insulin resistance is the decreased ability of our cells to partition fuel. It can be compared to someone hearing a noise such as their neighbour playing music, but after a while their brain “tunes out” the noise.  Even if the neighbour gradually turns up the volume of the music, the person’s brain compensates by further tuning out the increased noise. To compensate for insulin resistance, the β-cells of the pancreas begin producing and releasing more insulin, which results in hyperinsulinemia – too much insulin in the blood.

In the early stages the body is simply trying to keep blood sugar levels within its normally tightly regulated range by making and releasing more insulin to force the cells of the body to take up the excess glucose and burn it, but this just makes the problem worse. It is the increasingly high circulating levels of insulin that contribute to the health risks and metabolic disease listed above.

Just as high blood sugar is not necessarily associated with high circulating levels of insulin, neither is obesity.  Approximately 1/3 of insulin-resistant people are lean. A person who is obese simply makes more fat cells (adipocytes) in order to store the excess energy as sub-cutaneous fat (fat under the skin) which serves as a protective mechanism. Contrary to what most people assume, people don’t become insulin resistant because they are fat; becoming fat may be a protective response to high levels of circulating insulin. Those who are lean but insulin-resistant are thought to have a lower ‘personal fat threshold’ than those that become overweight of obese. That is, they are limited in terms of how many new fat cells their body can make to store excess energy, so they store the excess energy in and around their organs in what’s called visceral fat.  This is where the metabolic disruption occurs.  Whether the person is obese or lean, once they have exceeded their personal fat threshold, the result is the same.

Assessing whether my clients have higher than ideal levels of insulin is as important as assessing whether they already have higher than ideal levels of blood sugar, in fact it is even more important. When people already have pre-diabetes or Type 2 Diabetes, they’ve likely been told by their doctors that they are increased cardiovascular risk and that this is a risk factor for other metabolically related conditions, including high blood pressure, fatty liver disease, Alzheimer’s and other forms of dementia and certain types of cancer. Having normal blood sugar many are told “everything is fine” when very often it is not.  These people are at risk and don’t even know it.

It is important that my clients know whether they have symptoms of hyperinsulinemia and to help them understand the factors that contribute to it. This helps people to have the motivation to make necessary dietary and lifestyle changes to reduce their disease risk and totally avoid the progression to Type 2 Diabetes, long before blood sugar levels begin to rise.

For those that already are pre-diabetic or been diagnosed as having Type 2 Diabetes, it is not too late. A carbohydrate-modified diet as well implementing very specific lifestyle changes makes the reversal of symptoms entirely possible and does not require dietary or exercise extremes.

I think that for too long we as clinicians have tackled this as an insulin problem caused by overweight and created by “eating too much and moving too little” rather than as the exact opposite; that people get overweight because of an underlying insulin problem. When we address hyperinsulinemia, weight, blood sugar, blood pressure and high cholesterol and triglycerides are corrected. There are studies documenting this (covered in previous articles) and my “A Dietitian’s Journey” tells my own sample-set-of-one story reversing Type 2 Diabetes that I had for 10 years, as well as the related conditions of high blood pressure and abnormal cholesterol and triglycerides. It can be done.

Have questions as to how I can help you either in-person in my office or via Distance Consultation? Please send me a note using the Contact Me form above and I will reply as soon as I am able.

To our good health!

Joy


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References

Reaven, G., Insulin resistance, type 2 diabetes mellitus, and cardiovascular disease: the end of the beginning. Circulation, 2005. 112(20): p. 3030-2.

Reaven, G.M., Pathophysiology of insulin resistance in human disease. Physiol Rev, 1995. 75(3): p. 473-86.

Taylor, R. and R.R. Holman, Normal weight individuals who develop type 2 diabetes: the personal fat threshold. Clin Sci (Lond), 2015. 128(7): p. 405-10.

Reaven, G., The metabolic syndrome or the insulin resistance syndrome? Different names, different concepts, and different goals. Endocrinol Metab Clin North Am, 2004. 33(2): p. 283-303.

Crofts, C., et al., Identifying hyperinsulinaemia in the absence of impaired glucose tolerance: An examination of the Kraft database. Diabetes Res Clin Pract, 2016. 118: p. 50-7.

Ludwig, D.S. and M.I. Friedman, Increasing adiposity: consequence or cause of overeating? JAMA, 2014. 311(21): p. 2167-8.

Crofts, C., Understanding and Diagnosing Hyperinsulinemia. 2015, AUT University: Auckland, New Zealand. p. 205.

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Author: BBDN

Joy Y Kiddie MSc., RD - I'm a Registered Dietitian in private practice in British Columbia, Canada that provides services in-person in my Coquitlam office, as well as by Distance Consultation (using Skype / telephone).