FEATURED: Insulin Resistance

Insulin resistance is a condition where your body keeps producing more and more insulin in order to transport glucose out of the blood and store the excess by converting it to fat. When cells have become resistant to insulin, glucose builds up in the blood and results in “high blood sugar”. The problem is that high blood sugar is a symptom of the problem, it is not the problem itself.  Insulin resistance is the underlying cause and is highly significant to those with completely normal blood sugar levels.

Those with high fasting blood glucose may notice symptoms that are associated with Type 2 Diabetes; including excess urination and excess thirst. This is the body’s way of trying to dilute the high levels of glucose in the blood. A very sobering fact is that 75% of people with insulin resistance have normal fasting blood glucose levels and don’t know that they are insulin resistant.

They have NO symptoms whatsoever.

They don’t know that they are at increased risk for heart attack and stroke.

The Silent Risk of Insulin Resistance

Insulin resistance is a risk factor for atherosclerosis* – also called “hardening of the arteries”. Atherosclerosis is where plaque builds up inside the body’s arteries and if the plaque build-up occurs in the heart, brain or kidney, it can result in in coronary heart disease, angina (chest pain) or chronic kidney disease. These diseases are normally associated with Diabetes, but it is the underlying insulin resistance of Diabetes that creates the increased risk – not the high blood sugar itself.  Worthy of note, it is being insulin resistant that increases one’s risk – whether or not one also has high blood blood sugar.

The plaque that builds up in atherosclerosis may partially block or totally block blood flow to the heart or brain and if a piece of the plaque breaks off or if a blood clot (thrombus) appears on the plaque’s surface – this can block the artery  resulting in a heart attack or a stroke (in the brain).

Three quarters of people with normal fasting blood glucose are at increased risk of atherosclerosis and as a result, to heart attack and stroke due to insulin resistance and they don’t even know it, because their blood sugar is normal!

* a few recent references (there are many more):
Pansuria M, Xi H, Li L, Yang X-F, Wang H. Insulin resistance, metabolic stress, and atherosclerosis. Frontiers in Bioscience (Scholar Edition). 2012;4:916-931. 

Santos, Itamar S. et al., Insulin resistance is associated with carotid intima-media thickness in non-diabetic subjects. A cross-sectional analysis of the ELSA-Brasil cohort baseline, Atherosclerosis 2017 Mar 10;260:34-40

Insulin Resistance with Normal Blood Glucose

Dr. Joseph R. Kraft, MD was Chairman of the Department of Clinical Pathology and Nuclear Medicine at St. Joseph Hospital in Chicago, Illinois for 35 years. He spent a quarter century devoted to the study of glucose metabolism and blood insulin levels.

Between 1972 and 1998, Dr. Kraft measured the Insulin Response to a carbohydrate / glucose load in almost 15,000 people aged 3 to 90 years old using a 5-hour oral glucose tolerance test with insulin assays. Data from 10,829 of these subjects indicated that 75% of subjects were insulin resistanteven though their fasting blood sugar level was normal.

That is, having a normal fasting blood glucose level, and normal HbA1C level does not preclude someone from being insulin resistant and at increased risk for heart attack and stroke.

The American Heart Association states on its web page that;

“exactly how atherosclerosis begins or what causes it isn’t known, but some theories have been proposed. Many scientists believe plaque begins to form because the inner lining of the artery, called the endothelium, becomes damaged. Three possible causes of damage to the arterial wall are (1) elevated levels of cholesterol and triglycerides in the blood (2) high blood pressure and (3) cigarette smoking“.

It is known that high triglycerides in the blood are largely a result of diets high in carbohydrates where excess carbohydrate that isn’t converted to glycogen and stored in muscle and liver is stored as triglyceride (three fatty acids attached to a glycerol molecule).

Insulin resistance in our cells, results in our bodies releasing more and more insulin in order to try to clear the same amount of glucose from our blood to store it in our liver as triglyceride (fat!). As covered in the blog post on the hormonal effect of insulin, it is the insulin which drives increased hunger and specifically increased craving for carbohydrates.  A viscous circle is created.  Diets that are 45-65% carbohydrate result in more and more insulin to handle the same carb load (that is the very nature of insulin resistance) and this increased insulin leads to even more insulin resistance, increased hunger and craving for….you guessed it: more carbs.

Since insulin’s main role is to store the excess glucose not needed immediately for energy or glycogen, to fat – our bodies produce more and more triglyceride (fat!) the more carbs we eat and the more insulin resistant we are. That is, a high carb diet results in high triglycerides – which the American Heart Association recognizes as playing a role in the development of atherosclerosis. That is because triglycerides are converted to VLDLs to transport fat around the body and when their triglycerides ‘passengers’ are depleted, what is left is LDL, the “bad cholesterol” we have all heard about.  The ONLY source of LDL is VLDL, and high triglyceride is largely the result of a diet that is too high in carbohydrate.

Insulin also plays a significant role in the regulation of blood pressure through its effect on sodium transport. As insulin rises, excess sodium is retained by the kidneys, increasing blood pressure.  Insulin resistance compounds this problem, causing blood pressure to rise even more.  It has long been known that people with Diabetes develop high blood pressure – but it is the underlying insulin resistance that is driving that, not the symptom of high blood sugar.

What is alarming is that based on Kraft’s research with ~11,000 people over 20 years, potentially 75% of people are insulin resistanteven though their fasting blood sugar level is normal. This insulin resistance drives the increased triglycerides and high blood pressure that characterize what the American Heart Associations states is believed what underlies the development for atherosclerosis – and the corresponding risk of heart attack and stroke.

Could insulin resistance be a silent killer?

Kraft’s Patterns of Insulin Response

Kraft plotted the data from ~11,000 subjects and five distinct Insulin Response Patterns emerged.

Insulin Response Curves – image adapted from Dr. Ted Naiman

‘Pattern I: is a normal, healthy insulin response to a standard glucose load. Dr. Kraft called this ‘Euinsulin’.

image by Joy Y. Kiddie MSc RD
Pattern I: Normal Insulin Response Curve

Pattern II – is a hyperinsulinemic insulin response to a standard glucose. Note that Pattern II is considerably greater than the normal insulin response curve (Pattern I) and this greater insulin response is sustained for 5 hours after the ingestion of the glucose. 

image by Joy Y. Kiddie MSc RD
Pattern II hyperinsulinemia compared to normal glucose response (Pattern I)

Superimposing the hyperinsulinemic insulin response of Pattern II over the normal Pattern I insulin response curve, it is easy to see how much higher the Pattern II (yellow curve) is over the normal Pattern I (green) curve.  This is the early stages of insulin resistance.

Pattern III – is a hyperinsulinemic insulin response to a standard glucose load. Compared to the normal insulin response curve (Pattern I), it much greater during for 5 hours after taking in the glucose.

image from Joy Y. Kiddie MSc RD
Pattern III hyperinsulinemia compared to normal glucose response (Pattern I)

Superimposing Pattern III (hyperinsulinemia) insulin response curve over the normal (Pattern I) insulin response curve, its easy to see how the insulin response is delayed (skewed to the right). This results in blood glucose remaining high, as insulin is not responding as it should. Keep in mind, this is occurring in people with normal fasting blood glucose levels.

The Pattern III curve also goes so much higher than the normal Pattern I insulin response curve – which means that more insulin is released and this higher insulin release is sustained for the 5 hours after taking in the glucose.

This is “silent” pre-diabetes  delayed insulin response and much higher levels of insulin for a much longer time – but with normal fasting blood glucose!

Pattern IV – Pattern IV is what Dr. Kraft calls “Diabetes in Situ” – literally “Diabetes in Place”. Looking at the Pattern IV insulin response curve compared to Pattern I (the normal insulin response), it is apparent that it is much greater for the entire 5 hours after taking in a standard amount of glucose.

image created by Joy Y. Kiddie
DIABETES IN-SITU: Pattern IV insulin response points compared to the normal Pattern I insulin response curve (in green)
image created by Joy Y. Kiddie MSc RD
DIABETES IN-SITU: Pattern IV insulin response curve compared to the normal Pattern I insulin response curve (in green)

Surprisingly, 40% of people with a Pattern IV Insulin Resistance still had normal fasting blood glucose

75% of people displaying Pattern II, II or IV insulin responses do not know that they are at greater risk for atherosclerosis and as a result to heart attack and stroke because they have no symptoms.  Their blood sugar levels are normal.

Finally, insulin resistance is the most common cause of Type 2 Diabetes.

Normal fasting blood glucose and normal HbA1C results do not reveal whether or not a person is insulin resistant – only a 2 hr glucose tolerance test can do that. Unfortunately, a 2 hour glucose tolerance test is usually only requisitioned when fasting blood glucose and HbA1C results come back abnormal.

Potentially, up to 75% of people are insulin resistance and have NO IDEA!

They are at increased risk for heart attack and stroke and have NO SYMPTOMS.

They don’t have increased thirst or increased urination like Type 2 Diabetics, but are at the same risk.

The Good News

The good news is, we can lower insulin resistance – and as a byproduct of that, shed excess weight in the process. This is accomplished through (1) a low carbohydrate diet with or without the use of (2) stretching the amount of time between meals (sometimes called “intermittent fasting”).

When designed properly, a low carbohydrate diet can provide all of the recommended intake of vitamin and minerals – while lowering insulin resistance.

That is where I come in.

I can assess your physiological needs for energy and nutrients and design an Individual Meal Plan that will enable you to lose weight, without being hungry all the time – and that will help lower your insulin resistance and the associated risk of cardiovascular disease related to insulin resistance.

Want to know more?

Click on the “Contact Us” tab above, and send me a note.

To good health!