Type 1 Diabetes and Type 2 Diabetes: Similar Name but Completely Different Diseases.
As a healthcare professional, I see widespread confusion between Type 1 Diabetes Mellitus (T1 DM) and Type 2 Diabetes Mellitus (T2 DM) among patients, healthcare providers, and the lay public. Because of this, I have decided to use my platform to help explain the difference between these two very different conditions. Much of the confusion between the two conditions comes from the similar name and the similar manifestation of elevated blood glucose levels. The goal of treatment in both conditions is to keep blood glucose levels within normal range. However, because they do not result from the same root cause, treatment, management, and education should be approached differently between the two.
What is Type 1 Diabetes?
First and foremost, T1 DM is an autoimmune disease. Although there are a few hypotheses about the potential causes of autoimmunity, T1 DM is not preventable. It is usually diagnosed in childhood, but can occur in adulthood as well. Onset is usually rapid and acute. Classic symptoms of T1 DM are polydipsia (excessive thirst), polyphagia (excessive hunger), polyuria (excessive urination), weight loss, dry mouth, and fatigue. If untreated, T1 DM can lead to Diabetic Ketoacidosis (not nutritional ketosis), which can be fatal. Signs and symptoms of DKA (in addition to those listed above) are dry mouth, lethargy, abdominal pain, vomiting, and coma. These symptoms warrant a trip to the ER. T1 DM is ultimately confirmed by an autoimmune antibody test.
The most important difference between T1 DM and T2 DM (I think), is that T1 diabetics and insulin DEFICIENT whereas T2 diabetics produce TOO MUCH insulin leading to insulin resistance. What does this mean?
Insulin often gets a bad rap, but it is necessary for life. It helps cells get nutrients to function. It enables blood sugar enter cells, keeping blood sugar in a normal range. In T1 diabetics, the body attacks its own insulin producing cells in the pancreas (beta cells). Without beta cells, the body lacks the ability to make insulin and sugar begins to accumulate in the blood. Because cells can't get nutrients (no insulin), the body thinks it is starving and starts breaking down tissue for nutrients. This is why weight loss and hunger occur. The kidneys desperately try to rid the blood of the excess sugar by increasing urine output, which leads to excessive thirst. Without insulin, the body literally starves in an environment of excess sugar. The only treatment is insulin injections. Unlike T2 DM, this is not an issue of poor dietary or lifestyle choices, or lack of exercise. It is a deficiency in a hormone (insulin) that is essential for life. T1 DM must be on insulin therapy to live. Once insulin therapy is underway, it can be tricky to mimic physiological insulin secretion with injections or pump therapy, which can result in uncontrolled blood sugar. There are lifestyle and diet modifications that can help to obtain better control, but all efforts must be in conjunction with insulin administration via a pump or injection.
How is this different from Type 2??
To contrast, T2 DM results from TOO MUCH insulin production in the body. How does this happen? I discuss T2 and pre diabetes in length here, but to recap. The development of full-blown T2 DM is a long process (unlike T1 which happens relatively quickly). After years of chronically elevated blood glucose levels (as a result of diet and lifestyle factor), cells stop responding to the action of insulin. They become "insulin resistant" which is similar to becoming tolerant to alcohol. It takes more and more insulin secreted from the pancreas to achieve the same result and keep blood glucose within normal range. In fact, before someone ever has high blood sugar, they will usually have extremely elevated levels of insulin circulating throughout the body. This is an effort of the pancreas to overcome the insulin resistance of the cells. So to reiterate, in this case T2DM, we have extremely high insulin levels occurring with insulin resistance. With T1 DM, we had TOO LITTLE insulin and starving cells. After awhile in T2 DM, the beta cells will not be able to continue over producing insulin to compensate for the chronically elevated blood sugars and insulin resistance. The pancreas starts to burn out. Beta cell function declines and insulin levels drop, allowing blood sugar to become elevated. This is when someone is diagnosed as T2 diabetic. Unlike T1 diabetics, T2 diabetics always produce some level of insulin, just not enough to overcome the insulin resistance or compensate for a high carbohydrate diet. Additionally, because they still produce insulin, T2 Diabetics have the option of taking a variety of oral medications that increase insulin sensitivity or restore beta cell function. There are very very limited oral medications for T1 DM.
T1 diabetics need insulin injections to live. However, I think it is backwards to treat T2 DM with insulin. Why? Because the root cause of the problem with T2 DM is TOO MUCH insulin. So why allow the fire to keep burning by adding more fuel? My approach to type 2 diabetes is to lower insulin levels as much as possible and to maintain stable blood sugar levels through application of a well formulated low carbohydrate diet. While T1 diabetics need insulin injections or pumps to live, T2 diabetes does not have to progress to insulin therapy if appropriate lifestyle interventions are applied.
I also strongly advocate using a low carb high fat diet in Type 1 diabetics. I use Dr. Berstein's approach with Type 1 diabetics. In my experience T1 diabetics who follow a low carb high fat diet have better blood glucose control, require less insulin, and have better long term outcomes than those that follow the ADA guidelines.