Insulin plays an important role in communicating to cells in the body when nutrients are available in the bloodstream. When the body fails to produce significant quantities of insulin or insulin receptors do not respond properly to insulin, nutrients accumulate in the blood. In type 1 diabetes, daily insulin injections or insulin taken nasally are required to help the body signal to the cells when nutrients are present. Type 1 diabetics who forget, or intentionally skip, insulin injections lose weight. For type 1 diabetics, skipping insulin can be fatal.
The Role of Insulin in Metabolism
After eating, the digestive tract converts protein, carbohydrate and fat into smaller or more water-soluble molecules that can pass from the digestive tract into the bloodstream. When the nutrients enter the bloodstream, the pancreas releases insulin into the blood. Insulin binds to insulin receptors on cell surfaces. This causes transporters to embed into the cell membranes. The transporters absorb the nutrients into the cells, which use them for energy, storage, repair or cell proliferation.
Diabetes
Diabetes is a condition that reduces the body's ability to inform cells when nutrients are available. In type 1 diabetes, the pancreas cannot produce enough insulin. In type 2 diabetes, the pancreas produces insulin, but insulin has difficulties getting its message across because the cells have become resistant to insulin. A diet that aims at slowing the flow of nutrients into the bloodstream can often control type 2 diabetes. Type 1 diabetics depend on insulin medication after each meal to ensure that the cells can use the nutrients from the food they eat.
Getting Off Insulin
When type 1 diabetics forget insulin doses or intentionally get off insulin, their cells do not get enough nutrients. So, the cells are starving. The body's normal response to starvation is to break down nutrients stored in the cells, including glucose stored as glycogen and body fat. When nutrients are released into the bloodstream, starving cells normally can get the fuel they need. But when insulin is lacking, nutrients accumulate in the bloodstream. Stored fat and glycogen keep breaking down, resulting in weight loss.
Health Consequences
When there is excess glucose in the bloodstream and the body cannot get rid of it by storing it or using it as energy, blood sugar rises to dangerously high levels. This is called "hyperglycemia." In hyperglycemia, excess glucose sticks to the inside of blood vessels. This constricts blood vessels and reduces the blood supply to vital organs. Some of the glucose is excreted in the urine through the kidneys, which can cause kidney failure. Constricted blood vessels and lack of blood supply to vital organs can lead to cardiovascular disease, strokes and nerve damage.
