There are a lot of myths surrounding the pathology of diabetes, and there are none bigger than the way we perceive the role of insulin in regulating blood sugar.
A lot of the dogma out there on this comes from our just guessing about this, and this would not be so bad if the guesses were more correct, but they aren't, and luckily science has our back here. The science here though is pretty much unknown to the medical community though, which will be pretty apparent to you as you read this and compare this with what you generally read about all of this.
For those who are interested in reading more, I will direct you to an outstanding paper published in a British medical journal in 2000, although it's been 15 years now, and things haven't changed much. We are understanding more and more about this disease but a lot of it is still based upon myths surrounding what insulin actually does and where things go wrong with our disease.
Let's start with the idea that high blood sugar involves reduced uptake of glucose. That's actually a big one, we look at people that have high blood sugar and think that they have a defect in glucose metabolism, and this is due to insulin resistance, so we need to increase insulin or increase uptake of glucose some other way to correct this.
However, it's been shown that when we have high blood sugar, our intake of glucose isn't diminished, it's actually increased. This actually makes a lot of sense, at least if you look at what happens with high glucose.
We tend to think that this high glucose is there because there is a backlog due to reduced uptake, we see normoglycemic people eat the same meal and they have normal blood sugar, we have high blood sugar, we must not be absorbing the glucose as well.
That's not what happens at all though. What does happen is that with diabetics, our liver secretes much too much glucose, and this is where the high blood sugar comes from, in spite of our being shown to uptake even more glucose than non diabetics.
If it weren't for this, we wouldn't be more at risk for damage from hyperglycemia, sugar in the blood doesn't cause this damage, it's too much glucose in the cells that do it. So we're actually being poisoned by too much glucose in our cells already, and now they want to give our cells even more. So instead of trying to solve the problem, which is too much glucose in our cells, we're looking to make that worse, and then we can rest easy thinking that we're fixing the problem, but this is a delusion.
As it turns out, peripheral glucose uptake is regulated by blood sugar levels, meaning that the higher one's blood sugar is, the more glucose our cells get. Insulin does facilitate this, but this is not the main role of insulin as far as regulating blood sugar goes. In fact, we can do quite well even without any insulin, the cells will take in the glucose they need, as long as we don't have excess hepatic glucose secretion, but that unfortunately not only comes with diabetes, it's the problem in diabetes.
The proper role of the liver in glucose metabolism is to keep our blood sugar stable, so for instance when we don't eat, the fasting state, it will secrete enough to keep our blood sugar at a healthy level, and in fact it is our supply here when fasting, as we are fasting and not getting any from digestion.
What happens though is that process gets broken, and the normal controls that keep this secreting glucose appropriately break down. This involves insulin resistance, but it's not the peripheral insulin resistance that we think it is, this is instead caused by insulin resistance in the liver and in the alpha cells of the pancreas, the cells that secrete glucagon, the hormone that tells the liver to secrete more glucose.
When we increase insulin, this acts upon the liver to slow down glucose production. Contrary to popular belief, increasing insulin doesn't upregulate peripheral glucose uptake, by the cells, it actually has been shown to reduce it. This makes sense actually once you realize that the problem is that we are getting too much glucose in our cells by the liver and now that's reduced, which is what we want actually.
The problem though is that excess insulin also creates more insulin resistance, and this applies to the liver as well, so in other words the liver gets insulin resistance and requires more and more insulin to recognize we have enough, and these higher levels also make it less insulin sensitive over time. So you can see how this problem can escalate, and this is why we tend to need higher and higher amounts of insulin to regulate our blood sugar properly, and using higher and higher amounts makes it harder and harder to achieve good control over time.