Diabetes explained in five minutes

Diabetes is one of the world’s fastest growing chronic conditions. Yet it’s widely misunderstood among those not affected by it. Here’s a five-minute read with what you need to know.

To understand diabetes, we need to start by looking at the role of carbohydrates in the human diet.

We typically eat ‘complex carbohydrates’ such as rice, bread, pasta, maize and potatoes for more than half our daily energy intake. These staples are labelled ‘complex’ because their molecular structure is such that it takes time for our digestive system to break them down and release their energy into our bloodstream as glucose. We also get energy from ‘simple carbohydrates,’ which our bodies break down into glucose much more quickly. These may be healthy foods such as fruit, or unhealthy ones like candy, soda and anything else containing raw sugar.

Insulin is the key

When non-diabetic people consume carbohydrates and glucose begins entering the bloodstream, the body triggers the release of a hormone called insulin. Produced in the pancreas, insulin can be thought of as a key to the cells of our muscles. It basically unlocks these cells so that the glucose in our blood can enter our muscles and feed them. This is how our body stores energy and – especially important for children – it’s how we grow.

For diabetics, the production of insulin or the body’s response to insulin doesn’t take place in the same way. Here we need to look at the difference between type 1 and type 2 diabetes.

Type 1 diabetes

For a type 1 diabetic, the pancreas does not produce insulin at all. Therefore, the glucose from the broken-down carbs simply stays in the bloodstream. In the short term this high blood sugar causes extreme thirst, irritation, disorientation, tiredness, frequent urination and – left unchecked – eventually a coma. But having high blood sugar regularly over the longer term – for many years – can ultimately cause blindness, gangrene, kidney failure and other life-threatening conditions. This is especially serious when one considers that type 1 diabetes is a chronic disease: once you have it, you have it for life.

Fortunately, type 1 diabetics can mimic the function of the pancreas by administering artificial insulin – either through injections or with an insulin pump – at a consistent rate throughout the day and night, and in spot dosages that correspond to their carbohydrate intake. People with type 1 diabetes need to check their blood sugar level every few hours, typically by pricking a finger for a drop of blood, but increasingly with an electronic sensor. They then calculate their carbohydrate intake for a meal and give themselves a corresponding dose of insulin. In a child, for instance, 10 grams of carbohydrate (roughly equivalent to a small slice of bread) may require half a unit of insulin. In an adult, perhaps double that amount or more.

Type 1 diabetics face a constant battle to get the dosage of insulin right. Give too little and blood sugar remains high, leaving you tired, irritable and thirsty. Give too much and you can inadvertently and rapidly plunge your blood sugar down to dangerous levels, causing a feeling of extreme weakness that requires the urgent ingestion of quick-burning carbohydrates. Many of us have experienced the effects of low blood sugar at some stage in our lives, usually from exercising without eating enough. But type 1 diabetics experience such episodes acutely and with much greater frequency.

What causes type 1 diabetes?

Type 1 diabetes begins when an autoimmune response (i.e. the body attacking itself) causes the insulin secreting beta cells in the pancreas to stop working. Nobody knows exactly why this autoimmune response occurs, but it’s believed to be triggered by an external factor such as a viral infection or an allergy of some kind – often during early childhood.

Type 1 diabetics are genetically predisposed to this autoimmune event. This does not mean that everyone who is genetically predisposed will end up with type 1 diabetes, but it does mean there is a greater risk of it. Also, certain cultures and geographies are genetically more at risk than others. Finland, for instance, consistently has the highest rate of type 1 diabetes in the world.

Type 2 diabetes

The major difference between type 1 diabetes and type 2 diabetes concerns the production and role of insulin. Whereas the pancreas of a type 1 diabetic does not produce insulin at all, the pancreas of a type 2 diabetic does produce insulin, but the body is unable to recognize and use it to process glucose. This is what’s known as “insulin resistance,” and it can typically be treated with oral medication that helps the body to lower blood sugar.

Although there is also an aspect of genetic predisposition to type 2 diabetes, it doesn’t play as strong a role as with type 1 diabetes. Whereas for type 1 this “heritability factor” (i.e. the role of genetics versus the role of the external environment) is approximately 80%, for type 2 it is around 10%. What this means is that environmental factors play a far more important role than genetics in determining susceptibility to type 2 diabetes, which is often triggered by poor diet and a sedentary lifestyle. Put simply, if you are genetically predisposed to type 2 diabetes – and you may not even know if you are – then you should be especially careful to eat well and exercise regularly.

Where to from here?

While there are marked differences between the causes and incidence of type 1 and type 2 diabetes, they share one very important factor: both are on the rise globally.

For type 1, this rise can be attributed to an increase in the unknown environmental factors triggering the initial autoimmune response, and/or to gene modifications that are being passed down from one generation to the next and increasing susceptibility to the condition.

For type 2, the rise is largely coupled with an increase in global rates of obesity driven by unhealthy eating and a lack of exercise.

These developments mean that in coming decades we will see more and more investment in diabetes research and care. There are already hundreds of companies working on diabetes: from trying to find ways to regenerate the original insulin producing beta cells, to producing apps that make it easier for diabetics to manage their carb intake, blood sugar and insulin dosages.

Look out for an article on some of these companies later this year…