November 18, 2022
 in 
Prediabetes & Diabetes

Insulin Resistance Test: What It Is And Why You Need It

Article highlights
  • HOMA-IR is an insulin resistance test that measures your fasting glucose and fasting insulin levels
  • Your cells can become insulin resistant up to ten years before any signs of dysregulated blood sugar.
  • The medical standard of care has it backward, only measuring insulin resistance if high blood sugar is already present. By measuring insulin resistance first, we can get ahead of high blood sugar issues in the future.
  • Most doctors won't prescribe HOMA-IR because insurance doesn't always pay, and it's not the standard of care. However, you can request this test from your doctor if you have concerns about your metabolic health. 
H

ow your body reacts in response to rising blood sugar gives you a significant window into your overall health. But what's the best way to test your efficiency in this metabolic process?

There are many ways to test blood glucose levels; for example, you can take an oral glucose tolerance test to assess how quickly your cells absorb glucose from your blood, or you can assess your fasting plasma glucose levels to spy on how long it takes for blood sugar to normalize after a meal. However, most people don't take into account a huge downfall of blood glucose tests — they don't account for insulin resistance.

Even an HbA1c blood test, which tells you what your blood sugar looked like over a 3-month range, can hide the truth if your body is still producing enough insulin.

In this article, you'll learn:

  • What the HOMA-IR test is, and how it works
  • Why insulin sensitivity is a much more important marker to test than blood glucose alone
  • Why your doctor likely won't prescribe a HOMA-IR
  • How understanding your body's insulin response could impact your health long-term

What Is HOMA-IR?

HOMA-IR (Homeostatic Model Assessment of Insulin Resistance) is a lab test that tells you how much insulin your body needs to make in order to control your blood sugar levels. In other words, it gives you insight into whether your insulin levels are within a normal range or if your pancreas is on overdrive. 

HOMA-IR is actually an indirect measure of insulin resistance, calculated from your fasting glucose and fasting insulin levels. While it is possible to measure insulin resistance directly, this type of test is very complicated and somewhat impractical, while HOMA-IR is much more accessible.

The healthy range for a HOMA-IR test is generally accepted as less than 1. Levels of 1.9 to 2.9 are considered early insulin resistance, and levels 2.9 and higher indicate significant insulin resistance. 

Signs of Insulin Resistance 

The tricky part of insulin resistance is that it won't necessarily present as blood sugar dysregulation because you can experience insulin resistance years before your blood sugar ever gets out of whack. With that being said, there are some tell-tale signs that you're insulin resistant, including:

  • Darkening of the skin around the armpits and back of the neck (acanthosis nigricans)
  • Skin tags
  • A waistline over 40 inches in men and 35 inches in women

Once your insulin resistance leads to high blood sugar, you may also begin to notice:

  • Increased thirst and urination
  • Fatigue
  • Dry mouth
  • Blurred vision
  • Depressed immunity 
  • unexplained weight loss or weight gain

What Causes Insulin Resistance?

Although there is some debate as to what causes insulin resistance in the first place, dietary factors and body weight are two strong predictors. Specifically, diets high in refined carbohydrates and low-quality fat like seed oils seem to interfere with insulin signaling and cellular processes[1]. 

Furthermore, many experts believe that central obesity (abdominal fat and visceral fat around the organs) can drive insulin resistance due to inflammatory chemicals produced by this type of adipose tissue. And, of course, refined carbohydrates and low-quality oils play a role in central fat accumulation[2]. 

Why Should You Look Into Getting A HOMA-IR?

To understand the relevance of testing insulin resistance, we first need to differentiate between IR and diabetes. 

The Difference Between Insulin Resistance and Diabetes 

Although insulin resistance plays a significant role in the progression of diabetes, these two terms actually describe two separate yet intimately related conditions.

Diabetes and prediabetes are diagnosed by looking primarily at one marker – your blood sugar levels. However, insulin resistance often occurs years before you see any changes in your blood sugar. Why? Because blood sugar stability is extremely important to your body, and before it lets things go haywire, it makes heroic efforts to keep blood sugar in balance. Therefore, once your cells start to lose their sensitivity to insulin, your pancreas responds by ramping up its production of insulin to keep your blood sugar stable. 

This process can continue for years, allowing your blood sugar levels to look normal and healthy while your pancreas wears itself out in the background. It's only when your pancreas is so spent that it can no longer produce sufficient amounts of insulin that you actually start to see issues with blood sugar control. 

In fact, Dr. Ben Bikman, a pioneer in the space of insulin resistance research, shares that insulin resistance can begin up to ten years prior to any blood sugar dysregulation.

So while insulin resistance causes issues with your cells' ability to take in glucose, diabetes occurs once your insulin production can no longer keep pace with your blood sugar spikes.

This is usually the time that you start to see irregularities in your blood sugar readings. Unfortunately, if you're already seeing blood sugar spikes and dips, it means that your pancreas has already been under fire for a significant amount of time.

This is why getting ahead of blood sugar irregularities is vital – if you can detect that your insulin levels are high prior to blood sugar dysregulation, you may be able to stop diabetes progression in its tracks. 

Why Is HOMA-IR Hard To Get Done With a Doctor?

So, why isn't insulin testing part of the standard protocol for diabetes prevention? And why are so many doctors resistant to ordering this test?

Put simply, the system has it backward. 

The standard medical protocol waits until you measure out of range for fasting blood glucose, at which point you can take a HOMA-IR or fasting insulin test to diagnose prediabetes or type 2 diabetes. And due to these standards, most insurance companies won't cover the HOMA-IR unless you've already had test results showing high blood sugar readings. For this reason, most doctors won't even consider prescribing HOMA-IR unless they see high blood sugar levels.

There is also a lot of confusion and misunderstanding in the medical field about what comes first; insulin resistance or high blood sugar. Many doctors likely see insulin tests as irrelevant if blood glucose looks okay. 

This is why it's crucial that you self-advocate with your doctor. Even if there is some pushback, if you feel you could benefit from digging deeper into your health, there is no reason they should deny you an insulin resistance test.

Can You Reverse Insulin Resistance?

A huge benefit of testing your insulin sensitivity is that it provides early detection that something is awry. This will increase your chances of reversing insulin resistance and preventing the onset of risk factors that come with reduced insulin sensitivity, such as diabetes, PCOS (polycystic ovary syndrome), heart disease, fatty liver disease, and metabolic syndrome.

These health problems can become chronic and life-threatening, so getting ahead of them is crucial for health and longevity.

Reversing insulin resistance doesn't happen overnight, but research shows that your cells can become resensitized to insulin signals with specific lifestyle changes, including physical activity and reduced carbohydrate intake[3,4].

Furthermore, these lifestyle changes may also reduce your risk for cardiovascular disease and metabolic syndrome by lowering cholesterol, regulating high triglycerides, and reducing BMI[5].

Takeaway 

Although the standard of care is to measure blood glucose levels before taking a look at what's happening with your insulin, this process is backward and misleading. With "healthy" blood sugar levels, many people believe their metabolic health is strong, even though it could be rapidly deteriorating in the background.

If you have reason to believe that your metabolic health is in danger, insist with your doctor or healthcare provider that you take an insulin resistance test. Hopefully, as more people request this type of testing, doctors will become more keen to prescribe it, and we can start to get ahead of the metabolic crisis that we're currently experiencing.

Citations

  1. Mirabelli, Maria, Diego Russo, and Antonio Brunetti. "The Role of Diet on Insulin Sensitivity." Nutrients 12.10 (2020): 3042.
  2. https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/prediabetes-insulin-resistance
  3. Venkatasamy, Vighnesh Vetrivel, et al. "Effect of physical activity on insulin resistance, inflammation and oxidative stress in diabetes mellitus." Journal of clinical and diagnostic research: JCDR 7.8 (2013): 1764.
  4. Foley, Peter J. "Effect of low carbohydrate diets on insulin resistance and the metabolic syndrome." Current Opinion in Endocrinology, Diabetes, and Obesity 28.5 (2021): 463.
  5. O’Neill, Blair J. "Effect of low-carbohydrate diets on cardiometabolic risk, insulin resistance, and metabolic syndrome." Current Opinion in Endocrinology, Diabetes and Obesity 27.5 (2020): 301-307.