A Answers (8)
The main causes of type 2 diabetes are:
- a condition called insulin resistance
- not making enough insulin to overcome insulin resistance
When you have insulin resistance, your body has trouble using insulin. Your cells resist using insulin so glucose cannot get into your cells. Your blood glucose becomes high. Your pancreas tries to keep blood glucose normal by making more insulin. At first this helps, but eventually your cells make less and less insulin. At the same time, your cells become even more resistant to insulin.
Your body gets most of its energy from glucose, a simple sugar that comes from carbohydrates in your diet. To get this glucose into cells requires a hormone called insulin, produced in the pancreas by special cells called beta cells.
When you eat and your digestive system breaks down food into glucose, beta cells receive a signal to make insulin. This insulin travels to certain cells (primarily muscle cells) and binds with special proteins on the surface of cells called insulin receptors, unlocking the cell and allowing glucose in. The receptor is like a doorway, and insulin opens the door so glucose can enter.
Insulin resistance is a condition where, in essence, the door gets jammed, and you need extra insulin to overcome the resistance. For a while, the extra insulin can keep blood sugar levels normal. But eventually your body tires of making so much insulin, the door stays closed and glucose levels in your blood rise. This is the start of diabetes.
Insulin is a hormone that pushes glucose into our cells for metabolism; insulin resistance is when organs are resistant to insulin and don't respond. Watch endocrinologist Reza Yavari, MD, explain insulin resistance and its impact on blood sugar.
Insulin resistance is a term to describe a malfunction in the body that prevents insulin from working properly. Produced by the pancreas, insulin is a key molecule that enables glucose, one of the body’s fuel sources, to enter the cells. In a person with diabetes, several malfunctions may occur at the same time. As a result, the glucose level in the blood remains high. The pancreas, thinking the glucose has been absorbed, secretes more insulin, which causes the body’s insulin level to remain high as well. Insulin resistance can be a warning of prediabetes or diabetes developing.
Insulin is one of the body’s hormones that controls blood glucose. Normally, when the body senses a higher glucose level, insulin is released to lower the level of glucose. But with insulin resistance, the body steadily becomes less responsive to the actions of insulin. Despite the high levels of insulin, the blood sugar levels rise, and eventually type 2 diabetes results.
People who are insulin resistant tend to gain belly fat -- with increasing waistlines (the apple shape as opposed to the pear shape). These individuals also have elevated triglycerides, low HDL cholesterol, high blood pressure, and high blood glucose levels.
Insulin resistance is at the heart of a number of serious health conditions, including obesity and diabetes. To learn what insulin resistance is, watch my video.
For reasons that aren't well understood, in some people, particularly the sedentary and overweight, insulin doesn't function properly; it seems that in these individuals, the cells themselves somehow become resistant to the action of insulin, so the insulin can't mediate the processes that make the glucose available to the tissues that need it. The result is that tissues starve for energy, even though ample fuel is available.
As the cells become resistant to the action of insulin and blood glucose levels rise, the body secretes more insulin in a futile effort to get energy to the cells, resulting in hyperinsulinemia. Researchers have recently found that hyperinsulinemia reduces secretion of sodium from the body, increasing blood volume and thus the risk of high blood pressure (hypertension or HTN) and the host of health problems that result, including increased risk of heart disease, kidney disease, and stroke. Hyperinsulinemia also triggers the nervous system to narrow blood vessels and causes vessel walls to thicken, making it more difficult for blood to flow through the vessels, further predisposing victims to HTN and increasing the strain on the heart. It also appears that insulin resistance is the condition underlying high levels of triglycerides and decreased levels of HDL or "good" cholesterol in the blood, both predictors of CVD, although the precise mechanism is not clear.
Insulin resistance is a condition common in type-2 diabetics in which the body produces large volumes of insulin, but cannot use it properly.
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