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Why and how did I get diabetes?

Diabetes occurs for a number of reasons, but the ultimate cause of the high blood sugar that characterizes the disorder is either deficiency of the hormone insulin or a combination of insulin deficiency and resistance of the body tissues to its actions. In response to food intake, insulin is released by specialized cells in the pancreas and is necessary for adequate amounts of glucose and other nutrients from food to be absorbed into certain tissues of the body. When insulin is lacking or the body resists its actions, the level of glucose in the blood becomes excessively high and diabetes is diagnosed. The difference in the balance between the two characterizes the two major forms of diabetes — type 1 and type 2 (see Question 2). Whatever the form of diabetes, its basis is to some extent hereditary and to some extent environmental. The hereditary contribution is more or less constant throughout recent human evolution. It is the environmental component that has changed markedly over the last 100 years, leading to the dramatic rise in the frequency of diabetes in almost all societies. You developed diabetes because either you are strongly predisposed due to hereditary reasons or because there are factors in your lifestyle and environment (such as gaining weight, getting insufficient exercise, taking certain medications) that increase the likelihood of diabetes or, as is usually the case, a combination of both. This is not all bad, because the environment and lifestyle can often be changed, with dramatic improvement in the severity of the diabetes. For more on this, see Question 5.

What is the difference between type 1 and type 2 diabetes?

Type 1 diabetes is entirely due to an almost complete deficiency of insulin. The deficiency is the result of the immune system erroneously attacking and destroying the insulin-producing cells in the pancreas. For the proper functioning of our bodies, it is necessary for insulin to be present at all times in the bloodstream and tissues, not only after we have eaten. Insulin is essential to maintain the structure of our tissues and prevent them from being broken down in an uncontrolled manner. Without any insulin present, our tissues literally melt away into simple compounds that leave our bodies when we urinate. Accordingly, people with type 1 diabetes have high levels of sugar and breakdown products of fat and protein in the bloodstream and urine and develop the typical symptoms described in Question 4.

Type 2 diabetes is due to a combination of our body tissues becoming resistant to the action of insulin (for the reasons described previously in Question 1) and the inability of the pancreas to make enough extra insulin to overcome it. Although this latter component of the problem is often viewed as a failure of the pancreas, it is not true in the strictest sense. While it is common for the insulin-producing capability of the pancreas to decline throughout later adult life, it was nevertheless sufficient throughout most of human evolution to prevent us from developing diabetes. It is only in recent times, when our lifestyle and environment have caused many of us to become very insulin resistant, that the insulin-producing capacity is unable to compensate. In the true sense, it fails because we impose an excessive load upon it. This is true, even for those of us who have a hereditary predisposition to becoming insulin resistant. The difference between the two forms of diabetes is illustrated in Figure 1.

Immune system

The body's system that protects it from foreign substances, cells, and tissues. The Immune system Includes the thymus, spleen, lymph nodes, lymphocytes, B-cells and T-cells, and antibodies.

Type 2 diabetes

Caused by a combination of body tissues becoming resistant to the action of insulin and the inability of the pancreas to make enough extra insulin to overcome it.

It is only in recent times, when our lifestyle and environment have caused many of us to become very insulin resistant, that the insulin- producing capacity is unable to compensate.

Figure 1 The cause of type 1 and type 2 diabetes.

 
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