Diabetes mellitus type 1, also known as type 1 diabetes, is an autoimmune disease that often begins in childhood as a result of the pancreas making no or too little insulin — but what exactly is happening inside the body?
Maintaining glucose balance
To understand what is happening inside the body of someone with type 1 diabetes, it is necessary to understand what happens inside the body of someone without the condition.
From the moment food enters the mouth, enzymes start breaking it down into simple molecules that can be digested and used to help the body function. This process continues throughout the digestive system as the food enters the stomach and intestine. Carbohydrates, in particular, are broken down into glucose and sent into the bloodstream to be absorbed by our cells to provide a source of energy.
Glucose levels in the blood are influenced by the pancreas, which is located in the abdomen near the stomach and has clusters of cells (called the islet of Langerhans) that produce two major hormones from two different cell types. The most abundant among the islet cells are the beta cells, which secrete the hormone insulin. Insulin lowers blood glucose levels by signaling cells to absorb glucose, which is then either converted into energy or stored as glycogen for later use, especially in liver and muscle cells.
A second group of cells, the alpha cells, secrete the hormone glucagon. Glucagon increases glucose levels in the blood by stimulating the breakdown of stored glycogen reserves into glucose and by increasing glucose secretion into the bloodstream. Insulin and glucagon function in tandem to maintain stable blood glucose levels.
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When glucose balance goes wrong
When your blood tests show high glucose, a condition known as hyperglycemia, this indicates that the sugar balance has been disrupted. In type 1 diabetes, this happens due to a deficiency in the amount of insulin produced by your body. So, what has gone wrong for this to occur?
The human immune system is programmed to differentiate between its own cells and foreign objects. Problems in the immune system lead to a failure to make this distinction and the immune system starts attacking the body’s own cells, resulting in autoimmune diseases. Type 1 diabetes occurs when the immune system starts destroying the insulin-producing beta cells of the pancreas. This happens due to a combination of genetic and environmental factors. The destruction continues over the course of several months and years during which time an individual remains asymptomatic, as a large percentage of the beta cells need to be destroyed before diabetes becomes evident.
Destruction of the beta cells results in an insufficiency of the hormone insulin and this causes increased blood sugar levels.
When the inside impacts the outside
The symptoms experienced by people with type 1 diabetes can tell us more about what is going on inside the body:
As glucose levels increase in the blood, the body tries to get rid of the excess sugar by secreting it into the urine. To maintain the urine concentration, more and more water is also excreted out by the kidneys, resulting in an abnormal increase in the amount of urine, also known as polyuria.
The excess loss of water through frequent urination results in dehydration, leading to excessive thirst, also known as polydipsia.
Fatigue and weakness
Insulin deficiency causes a subsequent deficiency in the absorption of glucose by the body’s cells and so the cells are unable to meet their energy needs. This results in fatigue and weakness.
To compensate for their inability to absorb glucose and convert it into energy, the cells start breaking down fat and glycogen stores in the muscles to obtain energy, resulting in weight loss.
Even after you have eaten a meal, since the glucose is not absorbed by the cells, signals are sent to the brain that you have not had enough food. This causes feelings of excess hunger.
High blood glucose over a long period of time can also damage the small blood vessels in the body. This can lead to blindness (when the blood vessels in the eye’s retina are damaged), numbness in the hands and feet (when the vessels supplying blood to the nerves are damaged), or kidney problems (due to damage to the blood vessels that form the filtration system of the kidneys).
The symptoms of type 1 of diabetes offer clues to what is happening inside our body due to lack or deficiency of insulin. It is important to pay heed to these symptoms to better understand what your body is trying to tell you so that you can better manage your condition.