Diabetes mellitus, or diabetes, is a condition in which insulin cannot inform the cells when nutrients are available in the bloodstream. When diabetes goes untreated, the brain interprets this as a mode of starvation, but because the cells cannot metabolize glucose, the biochemistry of the two states is different. During starvation, the body prefers to burn fat to metabolizing its own protein-rich tissue. But both protein and fat metabolize during initial phases of starvation. Protein turns into amino acids, which convert into glucose via a process known as gluconeogenesis. In the case of untreated diabetes, gluconeogenesis just leads to an accumulation of glucose in the bloodstream. So, the body must use fat to survive.
Diabetes
There are two main types of diabetes, type 1 and type 2. In type 1 diabetes, formerly known as juvenile diabetes, the beta cells of the islets of Langerhans in the pancreas do not produce enough insulin for the body to function. In type 2 diabetes, formerly known as late onset diabetes, insulin receptors have become resistant to insulin. So, they cannot signal to the cells when glucose is available in the bloodstream. Type 1 diabetics depend on daily doses of insulin taken intravenously or nasally. This treatment form doesn't work in the case of type 2 diabetes, as insulin receptors are equally resistant to natural and synthetic insulin. So, doctors normally prescribe blood glucose medications and a low-carb diet as a way of controlling type 2 diabetes.
Untreated Diabetes and Starvation
When diabetes goes untreated, cells do not register when glucose is available in the bloodstream. Glucose then accumulates in the bloodstream and eventually is excreted in the urine. The body's cells are still in need of energy. So, the body reacts to untreated diabetes the same way as it would to a state of starvation. In starvation, the body uses free blood glucose first. Then it breaks down the cells' stores of glycogen, the stored form of glucose, and uses that as a fuel. Finally, it breaks down fat and protein. Unlike most of the body's cells, the brain cannot use fat as an energy source. When glucose is limited, it uses ketone bodies, a by-product from fat metabolism. The order of breakdown of nutrients in untreated diabetes is similar to that in starvation.
Biochemical Differences between Diabetes and Starvation
During starvation, the body can still use the glucose that it obtains from breaking down glycogen or protein. Because the cells fail to register when glucose is available in individuals with diabetes, cells do not embed glucose transporters into the cell membranes. So, they cannot use glucose as a fuel. Glucose thus accumulates in the blood from the various metabolic processes the body instantiates in an attempt to accommodate the starvation mode.
Consequences of Protein Metabolism in Untreated Diabetes
Because untreated diabetes resembles starvation in creating an internal environment in which cells do not have any glucose available for use as energy, the body slowly breaks down protein-rich tissue, such as muscle and connective tissue. In starvation, the body can convert the resultant amino acids into glucose and use this as a source of energy. But in diabetes, this cannot happen. The continual secretion of starvation-hormone glucagon from the pancreas, furthermore, blocks synthesis of new protein. So, diabetics who do not receive treatment end up losing significant amounts of muscle mass and other protein-rich tissues.
References
- "Advanced Nutrition and Human Metabolism"; Sareen Gropper, et al; 2009
- "Clinical Nutrition"; Protein and Energy Metabolism in Type 1 Diabetes; Sadie L. Hebert and K. Sreekumaran Nair; February 2010
- "The Journal of Clinical Investigation"; Effects of Brief Starvation on Muscle Amino Acid Metabolism in Nonobese Man; T. Pozefsky, et al.; February 1976
- Mayo Clinic: Diabetes
- American Diabetes Association: Diabetes Basics
