Many people know that diabetics inject insulin under their skin to keep their blood sugar under control. And many understand that their own pancreas makes insulin whenever they eat a meal. Insulin is a hormone that helps you use the carbohydrates in your diet for fuel and, when you eat too many carbohydrates, insulin pushes them into your fat cells, where they can be stored. What you may not know is that too much insulin exerts deleterious effects on your body that can lead to heart disease.
Metabolic Syndrome
Scientists have identified a collection of physiologic traits, collectively called "metabolic syndrome," which are rapidly emerging as the No. 1 risk factor for heart disease among the U.S. population, according to American Family Physician. These traits include increased waist circumference or "central obesity," elevated blood pressure, insulin resistance and blood lipid abnormalities, such as high triglycerides or low HDL cholesterol. Among these traits, insulin resistance is gaining notoriety as the primary driving force behind metabolic syndrome.
Insulin Resistance and Blood Vessels
If you're overweight, there is a fair chance that the cells in your body are resistant to the insulin produced by your pancreas. According to a 1988 review in the journal Diabetes, 25 percent of non-obese people also exhibit insulin resistance. When your body doesn't respond normally to insulin, your pancreas produces more of this hormone to keep your blood glucose under control. According to Dr. Gerald Reaven, professor emeritus in medicine at Stanford University School of Medicine, this compensatory rise in insulin damages the lining of your arteries, because insulin tends to make your arteries "stickier" and more attractive to white blood cells that cause inflammation.
Inflammation, Cholesterol Plaques and High Blood Pressure
With time, inflammation created by white cells adhering to your arterial walls makes the arteries less pliable. This loss of elasticity increases your blood pressure -- much like forcing water through a rigid pipe generates higher pressures than pushing it through an expandable rubber hose. Additionally, inflammation of the arterial lining sets the stage for the formation of cholesterol plaques, which narrow the arteries and further increase blood pressure.
Putting It All Together
Since 1988, physicians have recognized the link between metabolic syndrome and cardiovascular disease, says the journal Diabetes. Insulin's contribution to arterial inflammation, increased blood pressure and atherosclerosis, or hardening of the arteries, is well established. As more Americans develop metabolic syndrome, the incidence of heart disease is expected to rise. Reducing your insulin levels and your risk for heart disease may involve lifestyle changes that include weight loss, regular exercise, a diet that includes fewer sugars and processed foods and, perhaps, medications.
