Glucose, a simple sugar, is the most available fuel the body uses to make energy. Levels of blood sugar, or blood glucose or plasma glucose, describe the amount of this fuel in the body. The pancreas makes and secretes the protein hormone insulin directly into the bloodstream to help maintain a steady blood glucose level by allowing cells to use glucose as the major source of energy. This prevents high levels of blood sugar, which presents health risks.
Relationship
Glucose and insulin differ in structure and function. They depend on each other to function properly. After a meal, glucose levels in the blood increase, and the pancreas secretes more insulin into the bloodstream, making glucose available for use by cells in the body. The liver and muscles store excess glucose as the more complex sugar glycogen. When blood glucose levels are low, the pancreas produces the hormon glucagon, which stimulates the release of stored glucose to make energy.
Normal Levels
Normal fasting glucose levels range between 3.5 and 6 mm per liter of blood, equivalent to about 60 to 110 mg per deciliter of blood. Many home test kits give accurate readings of blood glucose levels. A physician may order other forms of blood glucose measurements or insulin level tests. Normal fasting insulin levels are usually lower than 30 milli-international units per ml.
Abnormal Levels
Hyperglycemia, or high blood sugar, and hypoglycemia, or low blood sugar, can cause serious health effects. Hyperglycemia results when diseases of the pancreas lead to abnormally low insulin production or when cells cannot react appropriately to insulin; prolonged hyperglycemia leads to Type 2 diabetes Causes of hypoglycemia include tumors of the pancreas and misuse or abuse of insulin. The absence of insulin production causes Type 1 diabetes.
Considerations
Factors that affect the body's metabolizing of glucose include obesity, high cortisol, prolonged stress, short-term overfeeding and drugs including steroids, diuretics and some medications used to treat hypertension. Inflammation of the pancreas may destroy insulin-producing cells and cause hyperglycemia. Pregnancy predisposes some women to hyperglycemia because a hormone produced in pregnancy suppresses insulin production.
References
- "Manual of Nutritional Therapeutics"; D.H. Alpers, et al.; 2008
- "Cytokine Growth Factor Reviews"; Insulin Resistance in Adipose Tissue . . .; H. Ruan, et al.; Oct. 2003
