Insulin is a hormone produced by special cells, called beta cells, which are located in your pancreas. Insulin is intimately involved in the metabolism of fuel molecules in your body, particularly carbohydrates and fats. By stimulating receptors on the surfaces of cells in your liver, muscles and fat tissue, insulin triggers the absorption of glucose from your bloodstream. Depending on your body's needs, the glucose is then either metabolized for energy or stored for future use.
Insulin Levels in Diabetes
Type 1 diabetes--what used to be called juvenile-onset diabetes--is a condition caused by a lack of insulin production. People with this disease must take insulin to keep their blood glucose from going too high, because they do not make enough of their own insulin. Conversely, type 2 diabetes is characterized by higher-than-normal insulin levels. If you have type 2 diabetes, your blood glucose is elevated because your cells do not respond to the insulin made by your pancreas. In fact, your pancreas, sensing the additional glucose in your bloodstream, produces more insulin in an attempt to drive your blood glucose level down.
Metabolic Syndrome
In the 1980s, scientists first described a cluster of metabolic and physical factors that were linked to an increased risk for heart disease. Called syndrome X in 1988, the combination of high blood pressure, abdominal obesity, blood lipid abnormalities and insulin resistance have been re-designated as "metabolic syndrome," according to a 2004 review in "American Family Physician." Individuals with metabolic syndrome frequently have elevated insulin levels, as their bodies attempt to compensate for their insulin resistance.
Effects of High Insulin
Insulin exerts several physiologic effects in addition to its blood glucose-lowering properties. As reported in the February 2011 "Annals of Nutrition and Metabolism," insulin promotes atherogenesis, or hardening of the arteries, and stimulates cellular division, which may contribute to the development of some cancers. A 2011 study in "Autonomic Neuroscience" demonstrates that insulin also stimulates the sympathetic nervous system, which increases blood pressure and heart rate.
Considerations
A high serum insulin level is one characteristic of metabolic syndrome, which, according to Dr. Darwin Deen, a physician and nutritionist with the Albert Einstein College of Medicine, is probably the number one risk factor for heart disease in the U.S. population as of 2011. Other disorders, such as insulin-producing tumors, are much rarer causes of high insulin levels. Chronically elevated insulin levels may pose other risks, such as an increased risk for certain cancers or other chronic diseases. If you have been told that your insulin level is too high, discuss your options with your physician.
References
- "American Family Physician"; Metabolic Syndrome: Time for Action; D. Deen; June 2004
- "Annals of Nutrition and Metabolism"; Insulin Resistance: Pathophysiology and Rationale for Treatment; S. Muntoni; February 2011
- "Autonomic Neuroscience"; Cardiovascular Autonomic Responses to Hyperinsulinemia in Young Adult Males of Normal and Low Body Mass Index; S. Sucharita, et al.; January 2011
