It is difficult to give a precise definition of the word “diabetes,” because there is more than one type. For example, there is Diabetes Insipidus, a condition characterized by heightened thirst and dilute urine. Pre-diabetes is a condition where your sugar level tends to be higher than normal after fasting—The medical term is impaired fasting glucose. The sugar level can also be higher after eating—The medical term for this, is impaired glucose tolerance. Gestational Diabetes refers to the type that can occur during pregnancy.
However, when most people say “diabetes”, they are likely to be referring to Diabetes Mellitus, which is the condition typified by a high blood sugar level. This is a metabolic condition, where the body does not produce the correct level of insulin, or does not respond to the insulin produced, and causes the level of glucose in the blood to increase.
Thus, for this guide, we will use the term “diabetes” to refer to diabetes mellitus, unless specified otherwise.
The Importance of Insulin
The one common factor, in every type of diabetes, is the function of the hormone, insulin. It is responsible for how your body stores and uses the glucose obtained from the carbohydrates you eat.
Insulin is produced in the pancreas, in what are called beta cells. These cells primary function is to store and release insulin into the bloodstream. The beta cells respond to an increase in the amount of glucose in the blood stream, by secreting insulin.
Glucose is needed by the body, as it is can easily break it down for energy use. A person with low levels of glucose in their bloodstream may feel lethargic, dizzy, and their muscles may shake. However, a person with high amounts of glucose in their bloodstream may experience: blurred vision, a frequent urge to urinate, severe thirst, anxiety, muscle tingling, and fatigue.
Having an abnormally low or high level of glucose in your bloodstream is dangerous. Having a low amount of glucose may cause your body and brain to shut down; while too much glucose may be toxic.
A healthy body produces insulin, to ensure there is just enough glucose in the bloodstream for it to function on any given day. The amount a person requires, varies according to their daily physical activity. An athlete or a person that exercises regularly may need more glucose. A person who is not as active will need less glucose.
How Insulin Controls Your Blood Sugar
Understanding how insulin affects your blood sugar level, will enable you to understand the different types of diabetes mellitus. Insulin works to control the glucose in the body in the following way:
- When a person eats something, it is digested by their stomach and subsequently passes through the small intestine. Here, it is broken down by enzymes into small sugar units, one of which is glucose.
- The glucose is absorbed by the blood vessels in the small intestine. It is then transported to the cells, or parts of the body that need it, such as the brain or muscle tissue. However, the body does not use all the glucose obtained from food. It also stores some of the glucose in various parts of the body i.e. the liver, fat and muscle cells. This is especially the case if a person is not physically active, or their activity is restricted in some way e.g. illness.
- The body releases insulin, to control the amount of glucose stored in these cells. This process happens, when blood passes through the pancreas. The pancreas releases the beta cells; and if the cells realize there is too much glucose circulating in the body, it will release a proportionate amount of insulin to convert the glucose into a form that can be stored. It will not release insulin, if the amount of glucose is low.
Without insulin, the human body cannot use glucose or store it for energy. As a result, the glucose stays in the bloodstream, causing harmful side effects.
There are two types of Diabetes. We will go into greater detail, regarding Type 1 and Type 2 diabetes, in the following modules.