What is diabetes?

Diabetes means “syphon”?

diabetesWhen we think about diabetes we usually think about it as a problem with the way our bodies deal with sugar.

This is true, but the name of the condition, “diabetes”, comes from the Greek word for “syphon”.

Why syphon? Well, syphon is another name for a tube or pipe that a liquid flows through. Diabetes is defined as a condition that causes people to produce a lot of urine. In the past diabetes has been known as the “pissing evil”.

“Diabetes” doesn’t refer to sugar

So the word “diabetes” doesn’t really refer to sugar at all. Diabetes refers to the large volume of urine produced by people before they are treated for the condition.

Since diabetes is a condition that involves the production of a large volume of urine, people can sometimes get confused about it, so let’s look at the main types of diabetes.

Diabetes insipidus

Let’s talk about diabetes insipidus first, since this is different from the types of diabetes that we normally talk about.

Diabetes insipidus is caused by a lack of a hormone that helps our kidneys to reduce water loss from our bodies in our urine. This hormone is called anti-diuretic hormone, or ADH for short. Just in case you come across it, ADH is also called vasopressin. Isn’t biology confusing?

People with diabetes insipidus, who lack ADH, produce a large volume of urine because their kidneys can’t reduce the water loss.

So diabetes insipidus is usually nothing to do with sugar, so we won’t talk about it any more here.

Diabetes mellitus

The kind of diabetes that we are normally thinking of, that involves problems with sugar metabolism, should really be referred to as diabetes mellitus. Here’s a bit of history to help us see where the names associates with diabetes come from.

The urine taster…

I’m told that in the past there was a job in healthcare for someone called a urine taster. Honestly!

As you can imagine, the urine taster’s job was to taste urine.

So, when someone came in to the clinic who was producing a large volume of urine (i.e. they were peeing a lot), so they had diabetes, the urine taster would taste a sample of the urine.

If the urine didn’t really taste of anything, so it was “insipid”, the diagnosis was diabetes insipidus.

If the urine tasted sweet, because it had sugar in it, the diagnosis was diabetes mellitus. “Mellitus” means “like honey” in Greek.

So people with diabetes mellitus produced a large volume of urine and their urine contained sugar.

Now that we have excluded diabetes insipidus, we need to look at the differences between the two main types of diabetes mellitus – type 1 and type 2.

Hyperglycaemia and hypoglycaemia

There is quite a lot of confusion about the differences between the types of diabetes mellitus, and a better understanding of these differences will help to understand the advice and treatment that people receive.

The main problem that people with diabetes mellitus have is that their bodies have difficulty using sugar, and this leads to problems with the amount of sugar in their blood.

The main type of sugar carried in the blood is glucose, so the problems with the amount of sugar in the blood are usually that people have too much, hyperglycaemia, or too little, hypoglycaemia.


Hyperglycaemia (high blood sugar) tends to be a long term, or chronic, problem. This can lead to heart disease, kidney disease, eye damage, circulatory problems and wounds that don’t heal and become infected.


Hypoglycaemia (low blood sugar) is usually an acute, or emergency problem. People with low blood sugar can become confused, have seizures or lose consciousness.

So the key to treating diabetes mellitus involves control of blood sugar levels to avoid the problems associated with hyper, or hypoglycaemia.

Type 1 vs type 2 diabetes mellitus

Although the word “mellitus” isn’t usually included, when we are talking about diabetes we usually mean type 1 or type 2 diabetes mellitus. So what is the difference between the two?

Before we look at the differences between type 1 and type 2 diabetes mellitus it’s important to be aware that there are many similarities, which is why they are two variants of the same condition.

Both types can cause hyperglycaemia (high blood sugar), with all the associated health problems like vascular disease (increased risk of heart attack, strokes, and wound healing problems), and increased urine production.

The different ways that the two types of diabetes mellitus are treated are due to the differences between the conditions. The word “mellitus” isn’t usually included when people are talking about diabetes, but I’m going to include it here to be clear what we are talking about.

Normal glucose metabolism

Normally, after a meal the carbohydrates in the food are broken down in the digestive system to glucose, which is absorbed into the bloodstream through the walls of the intestines. This causes the blood sugar (glucose) to increase. The pancreas detects in increase in blood glucose and releases a hormone called insulin.

Insulin is a signal from the pancreas to the rest of the body that there is glucose available in the blood and the organs should take it up and use it. This gives the organs of the body glucose to use as fuel for energy, and causes the blood glucose to fall as it moves into body cells.

Causes of type 1 diabetes mellitus

Type 1 diabetes mellitus used to be called “insulin dependent diabetes”. That’s because it is usually treated with injections of insulin.

The most common cause of type 1 diabetes mellitus is the patient’s own immune system attacking and destroying the cells in the pancreas that produce insulin. This means that when blood glucose rises after a meal insulin isn’t produced.

The effect of this lack of insulin is that the cells of the body can’t take up glucose to use for energy, and the blood glucose levels stay high, which is called hyperglycaemia.

Causes of type 2 diabetes mellitus

Type 2 diabetes mellitus is a much more complicated disease. It used to be called “non-insulin dependent diabetes”, but a lot of people with this type of diabetes are actually treated with insulin, so that got a bit confusing. It makes much more sense to define the type of diabetes by the cause of the disease rather than the treatment.

Type 2 diabetes is associated with obesity and a lack of exercise. It also seems to run in families, so we can inherit an increased likelihood of developing the condition.

Rather than being due to a lack of insulin, type 2 diabetes is due to insulin resistance. This is where the body starts to ignore the insulin it produces, which means glucose isn’t take up by the body’s cells and the blood glucose stays high.

So why does the body start to ignore the insulin produced by the pancreas?

Insulin is produced by the pancreas when blood glucose rises after a meal. If we eat a lot then our blood glucose is raised due to all the carbohydrates we eat when we overeat. This means a lot of insulin is produced by the pancreas to get the body’s cells to take up the glucose.

As you know, if we take a drug too often our bodies will become tolerant, or resistant, to it. The same thing happens when the levels of insulin in our blood is constantly high due to overeating – we become resistant to it – this is insulin resistance.

Some people seem to inherit something genetic that makes this more likely to happen, which is how type 2 diabetes can run in families.

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