What Is Insulin Resistance, Exactly?

You may associate the term "insulin resistance" with diabetes, and you're not far off — it's tied to the development of the disease. But what is insulin resistance, exactly, and how can you prevent it?

We tapped an expert to learn everything about the condition, including what it is, how it's diagnosed, what happens if insulin resistance goes unchecked and how to prevent or manage it.

First things first, what is insulin? It's a hormone produced by the pancreas that helps transport the glucose (that's a type of sugar) in your blood to cells in your muscles, fat and liver to be used for energy, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).

You get glucose from the food you eat — that's why your blood sugar levels increase after a meal. Your pancreas then releases insulin into the blood so it can deliver that glucose to your cells, allowing the amount of sugar in your blood to drop back down to a healthy, stable level.

But this isn't the case if you have insulin resistance. This condition occurs when your cells are unable to take up glucose from the blood due to a reduced response to insulin, says Ruchi Gaba, MD, an endocrinologist and assistant professor of medicine-endocrinology at Baylor College of Medicine in Houston.

And when your cells don't properly respond to insulin, your pancreas starts to make more and more of the hormone to compensate, per the Cleveland Clinic. Sometimes, this increased insulin production is enough to keep your blood sugar levels in check.

But if your pancreas can't make enough insulin to overcome your cells' weak response to the hormone, your blood glucose levels rise, Dr. Gaba says. This elevated blood sugar can put you at risk for prediabetes and diabetes (more on that later).

While the exact cause isn't fully known, two major factors associated with insulin resistance are visceral obesity (having excess weight around the organs in your abdomen) and lack of physical activity, Dr. Gaba says. Eating processed, high-carbohydrate foods can also put you at risk for the condition, per the NIDDK.

According to the NIDDK and Cleveland Clinic, other risk factors for developing insulin resistance include:

• Age (people over the age of 45 are more prone to the condition)
• Genetics
• Family history of the condition
• You're of African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, Native Hawaiian or Pacific Islander American ethnicity
• Underlying conditions like a hormonal disorder, metabolic syndrome, polycystic ovary syndrome, high blood pressure and high cholesterol
• You have a history of gestational diabetes, heart disease or stroke
• You take certain medications like steroids, blood pressure medicine, HIV treatment or some psychiatric drugs

Unfortunately, there isn't a test that can quickly and easily tell you if you're experiencing insulin resistance, Dr. Gaba says.

What's more, there aren't any symptoms to alert you of the condition so long as your pancreas is producing enough extra insulin to keep your blood sugar levels in a normal range, according to the Cleveland Clinic.

It's not until the insulin resistance has advanced to elevated blood sugar — a condition called hyperglycemia — that you may start to notice changes. Per the Cleveland Clinic, these can include:

• Increased hunger and thirst
• Frequent urination
• Blurred vision
  
• Headaches
• Vaginal and skin infections
• Slow-healing cuts and sores

If insulin resistance progresses into prediabetes, you may also notice symptoms like:

• Darkened skin in your armpit or the back and sides of your neck (a condition called acanthosis nigricans)
• Skin tags
• Eye changes

Because there are no definitive symptoms for insulin resistance, it's typically a combination of factors that leads to a diagnosis.

For instance, blood tests may reveal heightened glucose and insulin levels, or having a waist measurement of 40 inches or more for people assigned male at birth and 35 inches or more for people assigned female at birth may indicate you're more likely to develop the condition, Dr. Gaba says.

Put plainly, unmanaged insulin resistance can lead to type 2 diabetes, Dr. Gaba says.

It also increases your chances of having high triglyceride levels, which are associated with an increased risk of stroke, heart attack and heart disease.

Insulin resistance can also make it tricker to control diabetes. "As insulin resistance increases, management of diabetes becomes harder, as more medication is needed to get enough insulin in the body to achieve normal blood sugar levels," Dr. Gaba says.

When it comes to treatment, no medications have been specifically approved to remedy insulin resistance, Dr. Gaba says.

However, "certain diabetes medications like metformin and thiazolidinediones are insulin sensitizers that help lower blood sugar, in part by reducing insulin resistance," she says.

While you can't change things like a genetic predisposition to diabetes or insulin resistance, you can give yourself the best shot at avoiding or managing these conditions by living a healthy lifestyle.

According to the Cleveland Clinic, this includes:

• Eating a nutritious diet full of vegetables, fruits, whole grains, fish and lean poultry, while also limiting trans and saturated fats, sugar, red meats, processed starches and large servings of carbs
• Regularly exercising
• If you have overweight or a large waist circumference: losing excess weight through a combination of diet and exercise