National Diabetes Information Clearinghouse
What is insulin resistance?
U.S. Department of Health and Human Services NATIONAL INSTITUTES OF HEALTH
Insulin resistance is a condition in which the body produces insulin but does not use it properly. Insulin, a hormone made by the pancreas, helps the body use glucose for energy. Glucose is a form of sugarthat is the body’s main source of energy. The body’s digestive system breaks food down into glucose, which then travels in the bloodstream to cells throughout the body. Glucose in the blood is called blood glucose, also known as blood sugar. As the blood glucose level rises after a meal, the pancreas releases insulin to help cells take in and use the glucose. When people are insulin resistant, theirmuscle, fat, and liver cells do not respond properly to insulin. As a result, their bodies need more insulin to help glucose enter cells. The pancreas tries to keep up with this increased demand for insulin by producing more. Eventually, the pancreas fails to keep up with the body’s need for insulin. Excess glucose builds up in the bloodstream, setting the stage for diabetes. Many people withinsulin resistance have high levels of both glucose and insulin circulating in their blood at the same time.
Insulin resistance increases the chance of developing type 2 diabetes and heart disease. Learning about insulin resistance is the first step toward making lifestyle changes that can help prevent diabetes and other health problems.
What causes insulin resistance?
Scientists haveidentified specific genes that make people more likely to develop insulin resistance and diabetes. Excess weight and lack of physical activity also contribute to insulin resistance. Many people with insulin resistance and high blood glucose have other conditions that increase the risk of developing type 2 diabetes and damage to the heart and blood vessels, also called cardiovascular disease. Theseconditions include having excess weight around the waist, high blood pressure, and abnormal levels of cholesterol and triglycerides in the blood. Having several of these problems is called metabolic syndrome or insulin resistance syndrome, formerly called syndrome X.
Metabolic syndrome is defined as the presence of any three of the following conditions: • waist measurement of 40inches or more for men and 35 inches or more for women • triglyceride levels of 150 milligrams per deciliter (mg/dL) or above, or taking medication for elevated triglyceride levels • HDL, or “good,” cholesterol level below 40 mg/dL for men and below 50 mg/dL for women, or taking medication for low HDL levels • blood pressure levels of 130/85 or above, or taking medication for elevated bloodpressure levels • fasting blood glucose levels of 100 mg/dL or above, or taking medication for elevated blood glucose levels
Source: Grundy SM, et al. Diagnosis and management of the metabolic syndrome: an American Heart Association/National Heart, Lung, and Blood Institute scientific statement. Circulation. 2005;112:2735–2752. Similar definitions have been developed by the World Health Organizationand the American Association of Clinical Endocrinologists.
What is prediabetes?
Prediabetes is a condition in which blood glucose levels are higher than normal but not high enough for a diagnosis of diabetes. This condition is sometimes called impaired fasting glucose (IFG) or impaired glucose tolerance (IGT), depending on the test used to diagnose it. The U.S. Department of Health and HumanServices estimates that about one in four U.S. adults aged 20 years or older—or 57 million people—had prediabetes in 2007. People with prediabetes are at increased risk of developing type 2 diabetes, formerly called adult-onset diabetes or noninsulindependent diabetes. Type 2 diabetes is sometimes defined as the form of diabetes that develops when the body does not respond properly to insulin,...