Insulin is a hormone made by the pancreas that helps glucose in your blood enter cells in your muscle, fat, and liver, where it’s used for energy. Glucose comes from the food you eat.
The liver also makes glucose in times of need, such as when you’re fasting. When blood glucose, also called blood sugar, levels rise after you eat, your pancreas releases insulin into the blood.
Insulin then lowers blood glucose to keep it in the normal range.
What is insulin resistance?
Insulin resistance is when cells in your muscles, fat, and liver don’t respond well to insulin and can’t easily take up glucose from your blood.
As a result, your pancreas makes more insulin to help glucose enter your cells. As long as your pancreas can make enough insulin to overcome your cells’ weak response to insulin, your blood glucose levels will stay in the healthy range.
What is prediabetes?
Prediabetes means your blood glucose levels are higher than normal but not high enough to be diagnosed as diabetes.
Prediabetes usually occurs in people who already have some insulin resistance or whose beta cells in the pancreas aren’t making enough insulin to keep blood glucose in the normal range.
Without enough insulin, extra glucose stays in your bloodstream rather than entering your cells. Over time, you could develop type 2 diabetes.
How common is prediabetes?
More than 84 million people ages 18 and older have prediabetes in the United States.1 That’s about 1 out of every 3 adults.
Who is more likely to develop insulin resistance or prediabetes?
People who have genetic or lifestyle risk factors are more likely to develop insulin resistance or prediabetes. Risk factors include
overweight or obesity
age 45 or older
a parent, brother, or sister with diabetes
African American, Alaska Native, American Indian, Asian American, Hispanic/Latino, Native Hawaiian, or Pacific Islander American ethnicity
physical inactivity
health conditions such as high blood pressure and abnormal cholesterol levels
a history of gestational diabetes
a history of heart disease or stroke
polycystic ovary syndrome, also called PCOS
People who have metabolic syndrome—a combination of high blood pressure, abnormal cholesterol levels, and large waist size—are more likely to have prediabetes.
Along with these risk factors, other things that may contribute to insulin resistance include
certain medicines, such as glucocorticoids, some antipsychotics NIH external link, and some medicines for HIV.
hormonal disorders, such as Cushing’s syndrome and acromegaly
sleep problems, especially sleep apnea
Although you can’t change risk factors such as family history, age, or ethnicity, you can change lifestyle risk factors around eating, physical activity, and weight.
These lifestyle changes can lower your chances of developing insulin resistance or prediabetes.
Being overweight or having obesity are risk factors for developing insulin resistance or prediabetes.
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What causes insulin resistance and prediabetes?
Researchers don’t fully understand what causes insulin resistance and prediabetes, but they think excess weight and lack of physical activity are major factors.
Excess weight
Experts believe obesity, especially too much fat in the abdomen and around the organs, called visceral fat, is a main cause of insulin resistance.
A waist measurement of 40 inches or more for men and 35 inches or more for women is linked to insulin resistance. This is true even if your body mass index (BMI) falls within the normal range.
However, research has shown that Asian Americans may have an increased risk for insulin resistance even without a high BMI.
Researchers used to think that fat tissue was only for energy storage. However, studies have shown that belly fat makes hormones and other substances that can contribute to chronic, or long-lasting, inflammation in the body.
Inflammation may play a role in insulin resistance, type 2 diabetes, and cardiovascular disease.
Excess weight may lead to insulin resistance, which in turn may play a part in the development of fatty liver disease.
Physical inactivity
Not getting enough physical activity is linked to insulin resistance and prediabetes. Regular physical activity causes changes in your body that make it better able to keep your blood glucose levels in balance.
What are the symptoms of insulin resistance and prediabetes?
Insulin resistance and prediabetes usually have no symptoms. Some people with prediabetes may have darkened skin in the armpit or on the back and sides of the neck, a condition called acanthosis nigricans.
Many small skin growths called skin tags often appear in these same areas.
Even though blood glucose levels are not high enough to cause symptoms for most people, a few research studies have shown that some people with prediabetes may already have early changes in their eyes that can lead to retinopathy.
This problem more often occurs in people with diabetes.
If you care about prediabetes, please read studies that intensive lifestyle change can benefit people with prediabetes, and this common food may help lower risk of high blood pressure, diabetes.
For more information about diabetes, please see recent studies about the key to treating type 2 diabetes, and results showing your age may determine whether diabetes drug metformin is useful to you.
Source: NIDDK
