Patients who are diagnosed with diabetes have what’s called hyperglycemia, which is a fancy word for high blood glucose or high blood sugar. Dr. Patel, can you tell us why people with diabetes have high blood glucose?
Of course, Dr. Hemstad. Diabetes is a disorder of the body’s metabolism. Metabolism is how the body converts digested food into energy so that the body can function properly.
In a body with a healthy metabolism, the digestive tract breaks down carbohydrates into glucose, a form of sugar that enters the bloodstream. A hormone called insulin helps the body’s muscle, fat, and liver cells absorb the glucose from the bloodstream and use it for energy.
Insulin is made in the pancreas, which is located behind the stomach. Clusters of cells inside the pancreas called islets contain beta cells. It is these beta cells that make the insulin and release it into the blood. In addition to helping cells absorb glucose, insulin also stimulates liver and muscle tissue to store excess glucose, called glycogen. Insulin keeps the liver from releasing glucose back into the bloodstream. It also keeps fat cells from releasing fatty acids to the rest of the body.
When blood glucose levels drop overnight or between meals, insulin levels drop too. Other cells in the pancreatic islets, called alpha cells, are then signaled to produce and release a hormone called glucagon. Glucagon stimulates liver tissue to break down glycogen into glucose and release it into the bloodstream.
In type 1 diabetes, the body’s immune system attacks and destroys beta cells, so the pancreas can no longer make enough insulin, or can no longer make insulin at all. Because the cells throughout the body need insulin to absorb glucose from the bloodstream, the destruction of beta cells results in a buildup of glucose in the blood, or high blood glucose.
In metabolic syndrome and type 2 diabetes, high blood glucose is a result of insulin resistance, which means the body’s cells don’t use the insulin being produced effectively. Beta cells react by producing even more insulin, but over time, the pancreatic beta cells become damaged due to inflammation, resulting in decreased insulin production. By the time someone is diagnosed with type 2 diabetes, at least 50 percent of insulin-producing cells have been destroyed. Glucose continues to build up in the bloodstream instead of being absorbed into the body’s cells.
Cells that don’t absorb glucose from the bloodstream don’t get enough energy to function well. In addition, proteins and lipids become glycated, or sugarized, from prolonged exposure to high blood glucose. These glycated proteins and lipids are known as advanced glycosylation end, or AGE, products. AGE products can lead to damage of nerves and blood vessels throughout the body, which in turn can lead to other serious health conditions such as:
- Cardiovascular disease
- Kidney disease
- Problems with sexual function
- Dental disease, and