Causes of Diabetes Mellitus Type 1 and Type 2

Diabetes mellitus, which is often termed as diabetes, is a condition, where the body either fails to produce enough insulin or cannot utilize it properly. This impairs normal sugar or glucose metabolism. Insulin is a hormone produced by the islets of langerhans of the pancreas. The islets of langerhans contain two types of cells, alpha and beta cells and the beta cells are responsible for producing insulin, which is required by the body for absorbing glucose from the bloodstream.

The carbohydrates that we consume are broken down into simpler molecules of glucose in the small intestine. Then, it is absorbed by the cells of the small intestine, from where they pass into the bloodstream, which carries them to the different parts of the body. Here, insulin plays an important role by facilitating the absorption of glucose by the cells of the muscles, fat tissues and liver. It also helps liver and muscle cells to store glucose in the form of glycogen and inhibits the use of fat for deriving energy. In the absence of insulin or in the case of insulin resistance, the body cells cannot absorb insulin from the bloodstream to obtain energy. This in turn, raises the blood glucose level, a condition known as hyperglycemia.

What Causes Diabetes Mellitus?

The main causes are not exactly known, though genetics, environmental factors, poor diet, obesity, medications, infections and sedentary lifestyle are regarded as some of the possible causes of the disease.

There are mainly two types of diabetes mellitus, known as type 1 and type 2 diabetes. Type 1 diabetes can be termed as an autoimmune disease, where body's own immune system attacks and destroys the beta cells of the pancreas. What exactly causes this autoimmune response is not known precisely, but genetics, environmental factors like viral infection are thought to be the important contributory factors. Genetics is another important cause and a person has 10% probability of developing the disease, if a first degree relative has diabetes. In case of a viral infection, viral protein that enters the body resembles beta cell protein. As a result, the immune system starts attacking both beta cells and virus, being unable to distinguish one from the other.

However, certain other factors also play a significant role in the process. T lymphocyte, a type of white blood cell is responsible for producing the immune factors, known as cytokines that destroy the beta cells of the pancreas. At the same time, several proteins like glutamic acid decarboxylase, insulin and islet cell antigens, act as autoantigens and stimulate the attack by the autoimmune factors.

On the other hand, type 2 diabetes is a bit different from the type 1, in the sense that here, insulin is produced by the beta cells, but cells cannot respond to it or utilize it properly. This condition is known as insulin resistance. Sometimes, in response to insulin resistance, excessive insulin is produced by the beta cells that eventually exhausts them and lowers the production of insulin significantly. Many believe that type 2 diabetes can also be caused due to shortage of insulin or production of abnormal insulin that fails to produce the desired results. The main risk factors for this disease are genetics, age, obesity, physical inactivity, certain medications and any kind of disease that can damage the pancreas.

The chances of developing diabetes rise with increasing age, while lack of exercise or physical activity can further raise this risk. Obesity is another important factor that can cause diabetes. In addition to all these factors, stress, low intake of proteins and fibers and high intake of refined foods, hypertension, infection of the pancreas and high level of serum lipids, cholesterol and triglyceride are also be associated with increasing the risk of diabetes.

Symptoms of Diabetes Mellitus

The common symptoms of diabetes are excess production of urine, excessive thirst, hyperglycemia or high level of blood glucose and loss of glucose in the urine. An increased deficiency of insulin alters energy metabolism and can cause unexplained weight loss. Some other symptoms of diabetes include blurred vision, fatigue, nausea and lethargy.

The primary treatment option for type 1 diabetes, is daily injection of insulin, while the type 2 diabetes is treated with sulfonylureas, alpha-glucosidase inhibitors, biguanides, thiazolidinediones, D-phenylalanine derivatives, insulin, etc. However, diabetes is a complicated chronic disease with no permanent cure, and along with medications, modifications in lifestyle such as diet modifications, weight control, regular exercise and physical activity are also important to effectively control the disease.