Last week, we looked at how Type 1 diabetes works in the body — how it starts, what it does to our insulin and blood sugar management system, and how it’s treated (all in very basic, CliffsNotes versions, of course). This week, we’re going to move on to Type 2 diabetes, and then look at the areas where these two diseases (which actually operate very differently inside the body in spite of the shared name) overlap.
So, what IS Type 2 diabetes?
Type 2 diabetes is much more common than Type 1. There are about 29 million people in the U.S. diagnosed with diabetes — of those, only 1.25 million have Type 1. In spite of the much higher prevalence of Type 2, the causes aren’t as well understood. We know that excess weight is linked to Type 2 diabetes, as is inactivity, age, and genetic makeup. But these are simply correlations, and it isn’t completely understood WHY these factors can lead to the development of Type 2 diabetes.
While we don’t necessarily understand why Type 2 diabetes starts, we do know the mechanisms for how Type 2 operates within the body. Unlike Type 1, which really only has one trigger, Type 2 has a few. Insulin resistance (a declining ability of the body’s cells to effectively interact with insulin and take in the sugar it is trying to deliver) and decreased insulin production both contribute to the disease. The result is elevating levels of sugar in the blood. However, unlike Type 1, where the escalation is relatively quick (since the insulin-producing beta cells are being actively killed off by the immune system), the escalation for Type 2 can be much slower. And this can be a problem. Why? Because it means someone can live for quite some time with blood sugar that is ELEVATED, but not high enough to land her in the hospital. And chronically elevated blood sugar levels are the prime cause for diabetes complications! With the increasing incidence of Type 2 diabetes, it is very important that anyone who carries any of the risk factors for this disease have his blood sugar checked at regular intervals by his doctor to avoid this prolonged period of undiagnosed high blood sugars.
Once someone IS diagnosed, the next step is treatment. The treatment for Type 2 is much more diverse than it is for Type 1. As you may recall, insulin therapy is the ONLY option for Type 1 diabetes, since the problem is the absence of insulin in the body (additional medicines can be added to the insulin, but taking insulin is unavoidable). But because Type 2 has multiple triggers and is less acute (decreasing ability to effectively use and produce insulin rather than the complete annihilation of the insulin-producing cells associated with Type 1), the treatment options are much more diverse. There are several classes of oral and injectable medications that can be taken for Type 2 diabetes (often given in combination).
Metformin, the most commonly prescribed drug for Type 2 diabetes, works by increasing the cells’ sensitivity to insulin and decreasing the production of glucose by the liver. Sulfonylureas and meglitinides work by increasing the body’s production of insulin. Thiazolidinediones work to lower insulin resistance in the body. DPP-4 inhibitors work to block a certain enzyme, helping incretin hormones to trigger insulin release and lower blood sugar. Alpha-glucosidase inhibitors help block the body’s digestion of carbohydrate, which lessens blood sugar spikes. The injectable medicine amylin slows stomach emptying, blocks the release of a hormone that raises blood sugar, reduces after-meal glucose release from the liver, and helps to lessen food intake. The injectable GLP-1 receptor agonists increase insulin release in response to eating. And finally, a recent addition is a group of drugs known as SGLT2 inhibitors, which prevent the kidneys from reabsorbing sugar back into the blood, instead forcing the excess sugar to be excreted in the urine.
In addition to oral and non-insulin injectable medications, insulin therapy is also on the table for people with Type 2 diabetes. If insulin production is weakened enough, it may be impossible to manage the disease without the assistance of injected insulin. However, because the cells that produce insulin in the body are intact (unlike Type 1, where the entire production line is simply destroyed and therefore unable to revive itself), the injected insulin is supplementing the body’s insulin, rather than replacing it. As such, the dosages may be lower than for someone with Type 1. Furthermore, because the decreased production is linked to issues such as weight and inactivity, it is possible for someone with Type 2 diabetes to come off injected insulin, while people living with Type 1 cannot ever come off injected insulin (until that golden day when a cure is found — though I’m not holding my breath on that).
Lastly, managing Type 2 requires a diet that minimizes “carbohydrate bombs” (my endearing term for meals containing large amounts of carbohydrates — which, as you may recall from last week, metabolize into sugar and move rather quickly to the blood). People with Type 2 diabetes generally take medications that provide an overall increase in insulin efficiency rather than injecting insulin in direct proportion to the amount of food being eaten. As such, a sugar spike can overwhelm the body’s ability to manage blood sugar more easily than it can for someone with Type 1, who can increase the insulin dose to match that increased carbohydrate intake (this is still NOT a great idea for us Type 1s, by the way — it’s just a little less likely to spike our blood sugar immediately after a meal).
Where Type 1 and Type 2 meet
I’ve spent the past two weeks talking about the many differences between these two diseases. I hope this is helpful not only for readers living with diabetes themselves, but for their friends and family. It can be frustrating for us Diabetians to always be lumped into one group when our management regimens are so different (particularly when well-meaning but ill-informed friends and family give us suggestions that don’t really apply to OUR type)! But there are areas of overlap, and I want to run through some of those areas now.
First, even though diet and exercise are more closely linked to management of Type 2 diabetes (since the triggers are so directly linked to weight and inactivity, and therefore improvement in these areas can lead to much more dramatic effects on the body’s own ability to manage blood sugar), both Type 1 and Type 2 diabetes benefit from good diet and consistent exercise. The reason is that both lower weight and increased activity correlate to increased insulin sensitivity. And that’s true whether the insulin in question is injected (as it ALL is for us Type 1s), or produced by the body. For Type 1s, more exercise and lower weight can lead to lower insulin ratios, and less insulin in the bloodstream. This is good for blood sugar control, and good for the body in general, as constantly high levels of insulin can carry its own set of negative side effects.
Another area of overlap is long-term complications, those dreaded consequences of prolonged high blood sugar. Long-term complications, which can include kidney disease, nerve damage, circulatory system problems, vision problems (even blindness in extreme cases), and amputations, come from prolonged high blood sugars. That is why we go to such lengths to keep our blood sugars as close to nondiabetic range as possible (completely normal ranges aren’t really possible for someone with diabetes, but with advances in management it is possible to come close).
Finally, recent years have seen an increase in the incidence of “double diabetes.” That is, people with Type 1 who ALSO develop the lowered insulin sensitivity associated with Type 2 diabetes. In fact, it is not uncommon for people with Type 1 diabetes and decreased insulin sensitivity to be prescribed metformin along with their injected insulin.
There is so much more to both of these diseases — how to manage them, how to understand them, how to build one’s life around them, how to manage the emotional stress, how to manage the practical day-to-day aspects, and on and on and on. Like I said last week, that’s why six bloggers can each write weekly posts on this website and not run out of topics. Right now, David Spero has a piece on managing the financial impacts of diabetes — something I didn’t even come close to touching on here! In the end, whether you have Type 1 or Type 2, knowledge is your most valuable asset! Keep reading, keep learning, and keep moving forward.