There are several things that distinguish Type 1 and Type 2 diabetes. One of them is how much insulin is present/available for use in the body of the person with diabetes.

A relative insulin deficiency implies that there is an availability of insulin. In other words, insulin is still being secreted, but the thing is – the body isn’t making enough insulin to keep up with its own demands for glucose regulation.

Absolute insulin deficiency implies that insulin is essentially absent. In some cases there is a tiny, tiny amount still produced, but not in enough quantity to maintain glucose well enough (in cases of T1 diagnosis when there is still this small amount being secreted, it is not enough to sustain life). In those that are prone to absolute insulin deficiency (T1’s) but that still produce that tiny amount, they are likely in the “honeymoon” phase of disease and that small amount will soon cease to exist.

Okay. So. Relative = some insulin production. Absolute= no insulin production. 

So, what does this matter? What’s the practical application of this topic?

1. Having some insulin production means that glucose will still be mediated, at least in part, by natural processes in the body (this is a good thing!).
2. Any amount of endogenous (made by the body) insulin production will make sudden and drastic glucose variations less in occurrence and less in severity. The more endogenous insulin there is, the less dramatic the glucose variation. Conversely, the less the body produces, the greater and more drastic the glucose variation. 

T1DM is almost always characterized by an absolute insulin deficiency. The time in which there may not yet be complete loss of insulin secretion is early on – at and just after diagnosis. It doesn’t always happen, but it happens often enough for it to have been given a name – The Honeymoon Phase. This period of time is as deceptive as it sounds; your body is helping you along a little bit with some insulin production, but pretty soon it’s going to be completely gone and you will soon be 100% (exogenous) insulin dependent. This will likely result in more drastic glucose variations. Why the abrupt loss of insulin secretion? In Type 1 the body undergoes an internal attack (we often refer to this as an autoimmune attack), whereby the body destroys the cells that produce insulin (the beta cells). Beta cell destruction is permanent; these things don’t magically reproduce the way that other cells in the body do. We have always believed this attack to be abrupt, out of nowhere so to speak. New research is showing that Type 1 diabetes is actually detectable much sooner than has historically thought to be. However, by time the disease progression meets current diagnostic standards, the majority of beta cells are gone. What is the implication here? This absolute insulin deficiency makes glucose regulation very, very difficult. In fact, at times, management is impossible. There is no way for insulin from outside of the body (coming from humans and animals) to mimic what the body does on its’ own. This deficiency is hard to chase. To illustrate – when a non-diabetic eats a piece of cake, their blood sugar slowly spikes and almost immediately comes down to a normal level. Despite best efforts (pre bolus, exercise, bolusing more for a high glycemic food), in a T1, efforts to inject insulin from the outside will rarely match that in which the body would have done naturally. In this case, the blood glucose would likely spike and stay high for an extended (and uncomfortable) amount of it. It’s not yet a perfect science. 

Type 2 Diabetes is characterized by a relative loss of insulin. As mentioned, there is still glucose dysregulation with relative insulin loss, but theoretically, it is “easier” to manage than an absolute loss of insulin. I recognize that perspective is everything. In no way am I attempting to downsize the immense impact of Type 2 Diabetes. I use the word “easy” in as scientifically a way as possible. My intention is to convey that, scientifically, we know that the more insulin that the body is using from its own self, the more well regulated glucose is. It is a fact. A relative insulin loss is most often accompanied by insulin resistance. The insulin loss is a true loss of insulin making capability; if the body is making 75% of the insulin that it used to, it will always be 75% or less; you don’t gain that back. But (big but), because relative insulin loss is very often accompanied by insulin resistance, the insulin loss appears more potent. Insulin resistance refers to the body’s inability to use the insulin that it does make efficiently. This is usually due to excess adipose tissue i.e. fat. The most amazing news is – while loss of insulin secretion is irreversible, insulin resistance is reversible. Insulin resistance can be overcome by weight loss. With insulin resistance, the body is not using the insulin it is making appropriately because there’s too much fat; when fat is lost, the insulin that is still being made becomes much more effective. This is the mechanism whereby many people with T2 are able to improve glucose control and reduce medication simply by weight loss. 

This is sort of a big topic. Foundational to understand diabetes, if you will. 

Cheers!