What is Insulin and How Does it Work?
In a previous article, we answered the question of “What is Glucose?” Today, we’re going to tackle a more direct issue facing people with diabetes: what is insulin, and how does it work? This question plays a much more direct role in everyday life, and it’s shocking how many people (even those with diabetes) simply don’t have any understanding of what insulin is and does.
The first part of the question is fairly straightforward. Insulin is a type of protein called a hormone that is produced by the pancreas. Specifically, it is produced by cells in the pancreas called beta cells. Once it is produced, insulin is slowly released into the body over the course of a day, with spikes in insulin release during and after eating.
Like all hormones, insulin is tasked with regulating the way our bodies function. While insulin actually has multiple functions in the body, the main one we are generally concerned with controls the body’s ability to process glucose, a sugar that serves as one of the most basic sources of energy for everything we do. Specifically, insulin works as a gate keeper between the blood stream and the interior of the body’s cells – it controls how glucose goes from the blood to the cells so that it can be used.
When the body doesn’t produce enough insulin naturally, glucose builds up in the bloodstream instead of being absorbed and used, which is what causes most of the negative symptoms and complications of diabetes. This is the problem faced by people with diabetes. In Type 1 diabetes, the body is unable to produce insulin at all, and in Type 2 the production of insulin is either impaired, or the body stops being able to respond to insulin as well, or both. The buildup of glucose in the bloodstream not only means that your body doesn’t get the energy it needs to grow and function. It also leads to the body wanting to get rid of the extra glucose through frequent urination, which causes further complications.
Types of Insulin
While the insulin taken by people with diabetes is marketed in four forms (more on those a little later), there are really only two types. The first is a long-lasting insulin that mimics the slow release of insulin throughout the day, and rapid-acting (or prandial) insulin that works just like the spikes in insulin release that happen when people without diabetes eat. More commonly, however, pharmaceutical companies modify their base insulin or mix types of insulins together to create more beneficial products for people with diabetes. These come in four main types:
Rapid-Acting Insulin – Begins working almost immediately (usually within 15 minutes), but has a short duration with a peak in one hour and a total duration of 2 to 4 hours.
There has been a lot of concern lately, though, that even rapid-acting insulin isn’t as fast to begin working and to peak as natural insulin. This is a challenge since it still requires users to plan insulin use ahead of time, or wait a potentially dangerous 15 minutes or longer for a rising blood glucose level to stabilise and begin dropping. This will pose even more challenges as technology like the “bionic pancreas[link to post]” is hampered because it can’t get insulin immediately enough to be truly “real-time”.
Short-Acting Insulin – Typically considered “regular” or “normal” insulin, it begins working in about 30 minutes, peaks in about 3 hours, and works for a total of up to about 6 hours.
Intermediate-Acting Insulin – Can take 2 to 4 hours to start working, but then continues working for up to 18 hours with a peak somewhere between 4 and 12 hours later.
Long-Acting Insulin – Works just like the steady insulin secretions of the pancreas, with effects starting after a couple of hours and lasting for up to 24 hours.
These “types” of insulin aren’t really different kinds of insulin, but rather the two basic kinds that are either mixed together for varying time ranges or mixed with chemicals that either speed up or slow down the rate at which the body absorbs the insulin.
Why Does Insulin Need to Be Injected?
Many people with diabetes often wonder why insulin, unlike many other common medications, can’t simply be taken as a pill. The problem is because insulin is a complex protein, unlike most medications. The human digestive system is basically built around the task of breaking proteins down into simpler components, so trying to take an insulin pill would result in the insulin being broken down by the body before it enters the bloodstream.
Still, there is hope, and many companies and researchers are working on build a mechanism which would allow insulin in pill form to bypass the digestive process and not break down before it can be absorbed. Some of these efforts are reportedly quite close, and we might see insulin pills hit the market in the next decade or so, much to the delight of anyone who hates having to constantly stick themselves.
In the meantime, managing insulin doses with technology like the Timesulin insulin pen replacement cap can go a long way in helping to simplify the dosage process. And with diabetes technology expanding at a record pace, who knows where we’ll be in ten years – we may not have to worry about insulin doses at all!