Understanding Type 2 Diabetes 

When your body is working normally, the food you eat is digested and used as fuel. This fuel gives energy to the body’s cells. When you have diabetes, the fuel can’t enter the cells. If not treated, diabetes can cause serious long-term health problems.

Outline of person eating sandwich showing liver, pancreas behind stomach, stomach, and small intestine.

How the body gets energy

The digestive system breaks down food. This results in a sugar called glucose. Some glucose is stored in the liver. But most of it enters the blood. It travels to the cells. They use it as fuel. Glucose needs the help of a hormone called insulin to enter the cells. Insulin is made in the pancreas. It is sent into the bloodstream. This is a response to glucose in the blood. Think of insulin as a key. When insulin reaches a cell, it attaches to the cell wall. This signals the cell to make an opening. Then glucose can enter the cell.

Cross section of blood vessel and cell showing insulin and glucose working together normally.

When you have type 2 diabetes

Early in type 2 diabetes, your cells don’t respond correctly to insulin. Because of this, less glucose than normal moves into cells. This is called insulin resistance. The pancreas then makes more insulin. But over time, the pancreas can’t make enough insulin to overcome insulin resistance. Less and less glucose enters cells. It builds up to a harmful level in the bloodstream. This is known as high blood sugar (hyperglycemia). The result is type 2 diabetes. The cells become starved for energy. This can make you feel tired and rundown.

Cross section of blood vessel and cell showing glucose building up in bloodstream because of insulin resistance.

Why high blood sugar is a problem

If high blood sugar is not controlled, blood vessels all over the body become damaged. Ongoing high blood sugar affects organs, blood vessels, and nerves. This raises the risk of damage to the heart, kidneys, eyes, nerves, and limbs. Diabetes also makes other problems more dangerous. These include high blood pressure, high cholesterol, and triglycerides. Over time, people with uncontrolled high blood sugar have a greater risk of being disabled or dying from some conditions. These include heart attack, heart failure, or stroke. They may also have problems in their eyes, kidneys, and nerves. These problems are from injury to small blood vessels.

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