. When doctors use the term “diabetes”, they are often referring to type-2 diabetes, as it is by far the most common.
The subtypes of Diabetes Mellitus include:
In addition to the main types mentioned above, other types of diabetes can be caused by certain drugs such as steroids, and diseases such as cystic fibrosis. There is also a type of diabetes known as Diabetes Insipidus, which has nothing to do with blood sugar or insulin and so is probably of little interest to you.
Before we begin discussing the types of diabetes, it would be useful for you to first have a basic understanding of of how glucose is regulated by your body, and the role that insulin plays in achieving this.
All of the subtypes of diabetes are caused by problems with an extremely important hormone called insulin, whose sole job it is to keep your blood glucose levels down.
But what actually is glucose? Glucose is basically another name for sugar, and it is one of the main sources of energy for all of the cells in your body. It comes from carbohydrate in the food that you eat and is stored in your liver in an inactive form called glycogen. When your glucose levels are low, such as after a period of fasting, the liver releases some of its glucose stores. It then enters the blood to be distributed around your body.
However, glucose is unable to get into your cells to provide them with energy without the help of insulin.
Imagine that the cell wall is dotted with hundreds of tiny doorways, called glucose transporters. These are tiny proteins which act as a “tunnel” to allow glucose to enter the cell. However, these doorways are locked most of the time. Insulin acts as the key to open these minute doorways allowing glucose to enter.
Insulin is produced by the pancreas, which is found just below the stomach. After you eat a meal and glucose starts to be absorbed, the pancreas detects it and begins to secrete insulin into the blood. The insulin circulates around the body and begins to unlock those little doorways. This allows the glucose to exit the blood and enter the cells. Therefore, the overall effect of insulin is to lower blood glucose. Once insulin has done its job and most of the glucose has moved into your cells, the pancreas detects this and stops producing insulin.
People with diabetes are unable to keep their blood glucose levels down becuase of a problem with their insulin.
Either your body is not producing enough insulin to cope with the amount of sugar in your blood (such as in type 1 diabetes), or else the insulin that is being produced is not as effective as it is supposed to be (known as insulin resistance – typical of type 2 diabetes).
Both of these problems cause glucose to build up in the blood.
If glucose levels reach a critical point, a condition known as diabetic ketoacidosis (DKA) can occur. This is a medical emergency and patients need immediate help by a medical professional. DKA usually only occurs in type 1 diabetics who have no insulin at all. It is very unusal in a type 2 diabetic, as they usually have some working insulin which prevents it from occuring. DKA is discussed further in the type 1 diabetes category.
If blood glucose remains elevated over a period of years this can cause serious damage to blood vessels, resulting in subsequent damage to organs with delicate vessels, such as the kidneys and the eye.
No one single person is attributed with the discovery of diabetes mellitus. Many doctors and scientists have made contributions to our current understanding of the disease, so it would be unfair to say that it was discovered by any one individual.
There are written accounts of people suffering from the disease dating back to 1500 BC in Egypt, but the first to give it a name was the Greek physician Aretaeus of Cappadocia around 200 AD, who described it as a condition where patients passed large amounts of urine. At the time, the prognosis was exceptionally poor, and Aretaeus noted that the patient’s life was “short, disgusting and painful”.
It was not until the 17th century that the term mellitus, from the Latin word for honey, was added by Thomas Willis. This was in reference to the fact that the urine of these patients tasted sweet, “as if imbued with sugar or honey”. Yes, that’s right… they actually tasted urine back in those days!! 100 years later, an English doctor named Matthew Dobson confirmed that the sweetness was due to an excess of sugar found in the blood and urine of diabetic patients.
Although we have known about diabetes since ancient times, it was not until the late 20th century and the advent of modern medicine that we began to understand the cause of the disease. In 1889, Joseph von Mering and Oskar Minkowski found that they could cause all of the signs and symptoms of diabetes in dogs by removing their pancreas. However, they did not know what the pancreas did exactly or why removing it caused a build up of sugar in the blood and urine.
The function of the pancreas and the hormone insulin was discovered in 1921 by Sir Frederick Grant Banting and Charles Herbert Best. They showed that they could reverse diabetes in dogs who have had their pancreases removed by giving them a cocktail made from a liquid extracted from the pancreas of a healthy dog. Banting and Best went on to isolate the hormone insulin, which led to the first effective treatment for the disease – injections of bovine insulin collected from the pancreas of living cows. It was in 1922 that the first diabetic patient was successfully treated with insulin.
As a result of their outstanding work, Banting and Best received the Nobel Prize in Physiology in 1923 for their discovery. The patent for insulin was made available without charge and diabetes therapy rapidly spread around the world.
In 1980, a company called Genentech developed a method of producing actual human insulin. Before this discovery. They achieved this by finding the genes responsible for making insulin in human DNA, which they put inside the genome of a special type of bacteria. This bacteria multiplied and began to produce and secrete large quantities of human insulin which is then purified. This replaced the bovine insulin that had previously been in use.
We have come a long way in 3500 years, however even with all of our technological advancement, diabetes mellitus still remains to this day a major cause of morbidity and mortality worldwide.
To learn more about diabetes, its signs and symptoms and the various treatment methods, visit Blood Sugar Simplified.