Insulin Resistance

Insulin is a hormone made in the pancreas. It regulates blood glucose and helps transport it from the bloodstream to cells that need it for energy.

If you develop insulin resistance, the cells in your muscles, fat, and liver are unable to process insulin normally, so the glucose continues to build up in your blood.

The pancreas generates more insulin to little or no effect, while your body stores the sugar in your liver and muscles. When there is no room for more, the sugar is converted into body fat.

Insulin resistance is a precursor to prediabetes and, eventually, type 2 diabetes.

High levels of blood glucose over an extended period of time can lead to a correspondingly high production of insulin in response. Over time, this can lead to your cells losing their ability to respond to insulin, which leads to insulin resistance.

As long as your cells are able to use the extra insulin made by your pancreas to absorb glucose, you may have insulin resistance without having diabetes.

In prediabetes, your blood glucose levels rise above normal levels, but not high enough for a diagnosis of diabetes. Prediabetes usually occurs as a result of insulin resistance.

If you have insulin resistance, it’s important to work with a doctor. They will routinely monitor your blood sugar or hemoglobin A1c (HbA1c or A1C) so they can determine whether you’ve developed diabetes.

Classic diabetes symptoms include:

• extreme thirst or hunger
• feeling hungry even after a meal
• increased or frequent urination
• tingling sensations in hands or feet
• feeling more tired than usual
• frequent infections
• evidence of high blood sugar levels in blood work

Some people with insulin resistance may also develop a skin condition known as acanthosis nigricans. It appears as dark, velvety patches often on the backs of the neck, groin, and armpits.

Some experts believe insulin directly and indirectly activates the insulin-like growth factor 1 receptors on types of skin cells called keratinocytes and fibroblasts. This could lead to the growth and development of acanthosis nigricans.

There’s no cure for this condition. However, if another condition causes these symptoms, treatment may help natural skin color return.

If you don’t have obvious symptoms, your doctor can usually detect prediabetes or diabetes with lab tests.

Though doctors don’t usually test for insulin resistance, the most accurate test is an euglycemic insulin clamp that’s used for research purposes.

A1C test

One way to diagnose prediabetes or diabetes is with an A1C test. This test measures your average blood sugar over the previous 2 to 3 months.

Generally, here is what the results mean:

• An A1C under 5.7% is considered normal.
• An A1C between 5.7% and 6.4% is diagnostic for prediabetes.
• An A1C equal to or above 6.5% is diagnostic for diabetes.

Your doctor may want to reconfirm the test results later. However, depending on the lab where you have your blood drawn, these numbers could vary by 0.1% to 0.2%.

Fasting blood glucose test

A fasting blood glucose test shows your fasting blood sugar level. You have this test done after not eating or drinking for at least 8 hours.

A high level may require a second test a few days later to confirm the reading. If both tests show high levels of blood glucose, your doctor may make a diagnosis of prediabetes or diabetes.

Generally, here is what the results mean:

• Fasting blood sugar levels under 100 milligrams/deciliter (mg/dL) are considered normal.
• Levels between 100 and 125 mg/dL indicate prediabetes.
• Levels equal to or greater than 126 mg/dL are diagnostic for diabetes.

Depending on the lab, these numbers could vary up to 3 mg/dL points in the cutoff numbers.

Glucose tolerance testing

A 2-hour glucose tolerance test may be another way to diagnose prediabetes or diabetes. Your blood glucose level is determined before this test begins. You then receive a pre-measured sugary drink, and your blood glucose level is checked again in 2 hours.

Generally, here is what the results mean:

• A blood sugar level under 140 mg/dL after 2 hours is considered normal.
• A result between 140 and 199 mg/dL is considered prediabetes.
• A blood sugar level of 200 mg/dL or higher is considered diabetes.

Random blood draws

Random blood sugar tests are useful if you’re experiencing significant diabetes symptoms. However, the American Diabetes Association doesn’t recommend random blood glucose tests for routine diabetes screening or for identifying prediabetes.

Testing for diabetes should begin at about age 40 years, along with the usual tests for cholesterol and other markers of health. Ideally, your doctor will request testing at your annual physical exam or preventive screening.

Your doctor may recommend testing at a younger age if you have these risk factors:

• low levels of physical activity
• a low HDL (good) cholesterol level or high triglyceride level
• a parent or sibling with diabetes
• high blood pressure (140/90 mm Hg or above)
• symptoms of prediabetes
• gestational diabetes diagnosis (a temporary condition that causes diabetes only while pregnant)
• had a baby who weighed more than 9 pounds
• stroke

Children and teens 10 to 18 years old may also benefit from diabetes screening if they have overweight and two or more of the above risk factors for diabetes.

If you have prediabetes, you may be able to prevent the condition from developing into diabetes with these health-promoting behaviors:

• Work toward including exercise as a part of your daily routine, preferably getting in 30 minutes at least 5 days a week.
• Try to eat a nutrient-rich, balanced diet as often as possible.
• If you have overweight, consider losing weight. Even reducing your body weight by just 7% can help lower your risk of developing diabetes.

Making health-promoting lifestyle choices is the best way to help get your blood glucose levels in the desired range.

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