Diabetes mellitus is a condition in which the body cannot properly process glucose after it is broken down from sugars and carbohydrates in food, according to WebMD. Diabetes mellitus is categorized as Type 1, Type 2 and gestational, depending on how the absorption is disrupted.
The body breaks down glucose for energy using a hormone called insulin, explains WebMD. Individuals with diabetes mellitus do not produce enough insulin to effectively break down the glucose taken in, or the insulin that they do produce does not effectively break down the glucose. Cells in the bloodstream cannot absorb the glucose in persons with diabetes, so it remains in the system, building up in its unprocessed state. Such a buildup can lead to damage to the liver, eyes, circulation and nervous system. If untreated and not controlled through diet and medication, diabetes mellitus can become life-threatening.
Type 1 diabetes is caused by the malfunction of the pancreas, which fails to produce insulin, explains WebMD. Those diagnosed with Type 1 diabetes commonly supplement their diets with insulin, injected just under the fatty tissue of the skin. The pancreas of those with Type 2 diabetes does produce insulin, but either it is not produced in enough quantity, or the insulin produced is ineffective in helping the body absorb glucose.