Type 2 diabetes

DEFINITION

Type 2 diabetes, once known as adult-onset or noninsulin-dependent diabetes, is a chronic condition that affects the way your body metabolizes sugar (glucose), your body’s important source of fuel.

With type 2 diabetes, your body either resists the effects of insulin — a hormone that regulates the movement of sugar into your cells — or doesn’t produce enough insulin to maintain a normal glucose level.

More common in adults, type 2 diabetes increasingly affects children as childhood obesity increases. There’s no cure for type 2 diabetes, but you may be able to manage the condition by eating well, exercising and maintaining a healthy weight. If diet and exercise aren’t enough to manage your blood sugar well, you also may need diabetes medications or insulin therapy.

CAUSES

Type 2 diabetes develops when the body becomes resistant to insulin or when the pancreas stops producing enough insulin. Exactly why this happens is unknown, although genetics and environmental factors, such as excess weight and inactivity, seem to be contributing factors.

How insulin works

Insulin is a hormone that comes from the gland situated behind and below the stomach (pancreas).

The pancreas secretes insulin into the bloodstream.

The insulin circulates, enabling sugar to enter your cells.

Insulin lowers the amount of sugar in your bloodstream.

As your blood sugar level drops, so does the secretion of insulin from your pancreas.

The role of glucose

Glucose — a sugar — is a main source of energy for the cells that make up muscles and other tissues.

Glucose comes from two major sources: food and your liver.

Sugar is absorbed into the bloodstream, where it enters cells with the help of insulin.

Your liver stores and makes glucose.

When your glucose levels are low, such as when you haven’t eaten in a while, the liver breaks down stored glycogen into glucose to keep your glucose level within a normal range.

In type 2 diabetes, this process doesn’t work well. Instead of moving into your cells, sugar builds up in your bloodstream. As blood sugar levels increase, the insulin-producing beta cells in the pancreas produce more insulin, but eventually these cells become impaired and can’t make enough insulin to meet the body’s demands.

In the much less common type 1 diabetes, the immune system destroys the beta cells, leaving the body with little to no insulin.

SYMPTOMS

Type 2 diabetes symptoms often develop slowly. In fact, you can have type 2 diabetes for years and not know it. Look for:

• Increased thirst and frequent urination. Excess sugar building up in your bloodstream causes fluid to be pulled from the tissues. This may leave you thirsty. As a result, you may drink — and urinate — more than usual.
• Increased hunger. Without enough insulin to move sugar into your cells, your muscles and organs become depleted of energy. This triggers intense hunger.
• Weight loss. Despite eating more than usual to relieve hunger, you may lose weight. Without the ability to metabolize glucose, the body uses alternative fuels stored in muscle and fat. Calories are lost as excess glucose is released in the urine.
• Fatigue. If your cells are deprived of sugar, you may become tired and irritable.
• Blurred vision. If your blood sugar is too high, fluid may be pulled from the lenses of your eyes. This may affect your ability to focus.
• Slow-healing sores or frequent infections. Type 2 diabetes affects your ability to heal and resist infections.

When to see a doctor

See your doctor if you notice any type 2 diabetes symptoms.