Overview
Insulin resistance is a metabolic disorder characterized by the body’s not properly using glucose, or blood sugar. A major feature of type-2 diabetes is insulin resistance. Abdominal obesity, or excess fat tissue in the abdomen, predisposes people to insulin resistance. People with abdominal obesity are also at higher risk for type-2 diabetes.
Abdominal Fat
Abdominal fat is of concern because it is very active in releasing hormones involved in metabolism and hunger. In addition, hormones released by abdominal fat are carried to the liver, where they affect blood lipid production, which may lead to levels of low HDL (good) cholesterol and high LDL (bad) cholesterol. The combination of low HDL cholesterol, insulin resistance, abdominal obesity, high blood pressure and high fasting blood sugar is called metabolic syndrome, and is a risk factor for cardiovascular disease and type-2 diabetes.
Association with Insulin Resistance and Diabetes
Abdominal obesity is related to both insulin resistance and type-2 diabetes. Although researchers are investigating the exact mechanism of these relationships, abdominal fat seems to affect hormones that are involved in appetite and metabolism. For example, fat in the abdomen secretes a type of hormone called adipokines (also called adipocytokines) that may impair one’s tolerance for glucose. Resistin is one such adipokine and is associated with insulin resistance and type-2 diabetes. A study published in the January 5, 2002 issue of “Lancet” determined that excess fat in the abdomen elevated resistin levels more than other types of fat. In contrast, resistin levels drop after losing weight and waist size.
Diagnosing Insulin Resistance
The glucose tolerance test measures blood glucose (blood sugar) after fasting for at least 8 hours and after drinking a sugared liquid (provided by a health care professional) 2 hours before the test. A blood glucose level between 140 and 199 mg/dL indicates a type of pre-diabetes called IGT (impaired glucose tolerance). People with IGT typically have a history of insulin resistance and are at risk for developing type-2 diabetes. Another measure of insulin resistance is the fasting glucose test, which evaluates blood glucose levels after fasting for at least 8 hours. Fasting glucose levels between 100 to 125 mg/dL may indicate a form of pre-diabetes called IFG (impaired fasting glucose) and risk for diabetes. Fasting insulin levels can also be assessed. A fasting serum insulin level that is higher than normal (about 60 pmol/L) may be a sign of insulin resistance.
Treatment
Insulin resistance can be treated through lifestyle changes in diet and physical activity. Eating foods high in fiber and low in processed carbohydrates, saturated fat and trans fats may be beneficial. Moderate levels of physical activity for 30 minutes or more on most days are recommended. Losing weight, aerobic exercise, strength training and healthy eating can also help reduce abdominal fat.
Prevention
Insulin resistance can be prevented through lifestyle approaches, according to the American Diabetes Association. This includes regular physical activity and healthy eating strategies. For overweight individuals and those at high risk of developing type-2 diabetes, moderate weight loss and reduced calorie and fat intake are recommended.
About this Author
Dr. Mary Lehrman is a licensed psychologist with a Ph.D. in health psychology. She has been published in academic journals and has more than 10 years of experience helping people improve their health.
