A Brief Review of Insulin Resistance

An Inflammatory Process

Insulin is a hormone that is released by the pancreas.  Its role in the body is to carry glucose molecules from the bloodstream to the organs, muscles, and cells in our body to be used as energy.  Blood sugars serve us best when they are controlled to within a healthy range (about 70-100 mg/dL) as a low blood sugar will make you feel lightheaded and shaky (not enough energy for your brain!) and a high blood sugar is doing insidious damage whether you feel it or not (think traffic jam of sugar molecules in the blood so that oxygen and nutrients don't get delivered quickly).  

A low and consistent amount of insulin is released to help control your blood glucose levels, as well as additional boluses of insulin following meals.  While insulin is responsible for this aspect of metabolism, sometimes the cells become less sensitive to identifying insulin (we tend to see this in a pro-inflammatory environment or in android obesity) and so the pancreas has to produce more to have the same metabolic effect.  Insulin Resistance is a term used to define a state in the body in which more insulin than should typically be necessary is required to produce the same effect.  This can be due to a combination of genetic, environmental and lifestyle factors.

Predecessor to Disease

Insulin resistance can be tied to obesity, metabolic syndrome (deserving of a whole other blog post), diabetes, high blood pressure, high cholesterol, cardiovascular disease and fatty liver.  It is also typically a predecessor to development of type II diabetes as the pancreas can meet this higher demand, but only for so long until it burns out and becomes reliant on exogenous insulin.

Insulin resistance is not diagnosed based on a specific lab value but by corroborating clinical findings to lab data.  The biggest ways to make an impact on slowing down or reversing this process is by the following:

  •  Maintaining a healthy weight - obesity (particularly holding onto weight around the middle of the body) is more closely linked with this process.
  • Eating right - eating a balanced diet and minimizing high glycemic index foods (those foods that spike your blood sugar levels and require lots of insulin to metabolize) makes a huge impact on insulin resistance.  Minimize sweets, sugar, candy, baked goods, white potatoes, refined grains, etc.
  • Exercising -  aerobic exercise (even without weight loss) increases the rate at which sugar is being used by the muscles and can help the muscle cells stay sensitive to insulin.


Does Dietary Fat Impact Blood Sugars?

Carb Counting and Exchanges

The American Diabetes Association currently promotes the teaching and utilization of carbohydrate counting (formerly exchange lists) as an effective means of managing diabetes.  [Of course it is important to remember that diet works in conjunction with medication for diabetes management.]  For those with type I diabetes who are not producing any insulin, the carbohydrate content of that meal is used to calculate the amount of insulin to be given exogenously.

Carb counting oversimplified: When the body breaks down a meal, the amount of carbohydrate within that meal drives blood sugar levels.  Managing the amount of carbohydrate consumed (ex. eating 60 grams vs 95 grams) leads to better blood glucose management.  

While the overarching principle is true, carb counting does not take into account protein or fat in that given meal, as those two macronutrients do not break down to sugar (directly).  So does fat eaten at that same meal impact blood sugars?  Evidence is starting to show us that free fatty acids circulating in the blood impair insulin sensitivity.

Research Brief

In a new article published in Diabetes Care (November 2012), researchers used a crossover design to follow seven people with Type I Diabetes and had them eat a high fat meal and low fat meal with identical carbohydrate content.  Using an artificial pancreas to monitor BG response over the next 18 hours, the high fat meal required higher insulin infusion than the low fat meal, and despite the higher insulin delivery, led to increased hyperglycemia (high blood sugar).

While this study is hardly enough to draw any sweeping conclusions, it is another step in the direction of understanding the impact of the total diet on diabetes management.  With more research it may lead to changes in dietary recommendations, carb counting, or even insulin algorithms.  

If you want to read the article in more detail please check out the abstract here!