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Diabetes Basics

What is diabetes?

Diabetes mellitus is a disease that prevents your body from properly using the energy from the food you eat. Diabetes occurs when either:

  • The pancreas (an organ behind your stomach) produces little insulin or no insulin at all. (Insulin is a naturally occurring hormone produced by the beta cells of the pancreas that helps the body use sugar for energy.)

-Or-

  • The pancreas makes insulin, but the insulin made does not work as it should. This condition is called insulin resistance.
Understanding metabolism

To better understand diabetes, it helps to know more about how the body uses food for energy (a process called metabolism). Your body is made up of millions of cells. To make energy, the cells need food in a very simple form. When you eat or drink, much of your food is broken down into a simple sugar called glucose. Glucose provides the energy your body needs for daily activities.

The blood vessels and blood are the highways that transport sugar from where it is either taken in (the stomach) or manufactured (in the liver) to the cells where it is used (muscles) or where it is stored (fat). Sugar cannot go into the cells by itself. The pancreas releases insulin into the blood, which serves as the helper, or the "key," that lets sugar into the cells for use as energy.

When sugar leaves the bloodstream and enters the cells, the blood sugar level is lowered. Without insulin, or the "key," sugar cannot get into the body's cells for use as energy. This causes sugar to rise. Too much sugar in the blood is called "hyperglycemia" (high blood sugar) or diabetes.

Two main types of diabetes

Type 1 diabetes

Type 1 diabetes occurs because the insulin-producing cells (called beta cells) of the pancreas are damaged. People with Type 1 diabetes produce little or no insulin, so sugar cannot get into the body's cells for use as energy. This causes blood sugar levels to rise. People with Type 1 diabetes MUST use insulin injections to control their blood sugar.

The damage to the insulin-producing cells in Type 1 diabetes occurs over a period of years. However, the symptoms of Type 1 diabetes might occur over a period of days to weeks. Type 1 is the most common form of diabetes in people younger than 20 years old, but it can occur at any age.

Type 2 diabetes

People with Type 2 diabetes produce insulin. However, there is either not enough insulin or it doesn't work properly in the body. When there is not enough insulin or the insulin is not used as it should be, sugar cannot get into the body's cells for use as energy. This causes blood sugar to rise. Type 2 diabetes is most common in people over age 45 who are overweight. Some people with Type 2 diabetes can manage it by controlling their weight, watching their diet, and exercising regularly. Others might also need to take an oral medicine and/or insulin injections.

Other types of diabetes

Specific types of diabetes might result from pregnancy (gestational diabetes), surgery, use of certain medicines, various illnesses, and other specific causes.

What are the symptoms of diabetes?

The symptoms of diabetes include:

  • Increased thirst
  • Increased hunger (especially after eating)
  • Dry mouth
  • Frequent urination
  • Unexplained weight loss (even though you are eating and feel hungry)
  • Weak, tired feeling
  • Blurred vision
  • Numbness or tingling of the hands or feet
  • Slow healing sores or cuts
  • Dry and itchy skin (usually in the vaginal or groin area)
  • Frequent yeast infections
Diabetes risk factors
  • A family history of diabetes
  • Race or ethnic background
  • Being overweight
  • History of hypertension (high blood pressure)
  • Abnormal blood cholesterol or triglyceride levels
  • Advancing age
  • Certain drugs (These might increase blood sugar.)
  • Years of heavy alcohol use
  • Smoking
  • History of gestational diabetes or delivery of a baby weighing more than 9 pounds.
  • History of autoimmune disease
  • Being at risk for diabetes

It is important to note that sugar itself does not cause diabetes. Eating a lot of sugar can lead to tooth decay, but it does not cause diabetes.

How is diabetes diagnosed?

Diabetes is diagnosed with fasting sugar blood tests or with A1c blood tests, also known as glycated hemoglobin tests. A fasting blood sugar test is performed after you have had nothing by mouth (eating or drinking) for at least 8 hours. Normal fasting blood sugar is less than 100 mg/dl. You do not have to be fasting for an A1c blood test.

Diabetes is diagnosed by one of the following:

  • Your blood sugar level is equal to or greater than 126 mg/dl.
  • You have two random blood sugar tests over 200 mg/dl with symptoms.
  • You have an oral glucose tolerance test with results over 200 mg/dl.
  • Your A1c test is greater than 6.5% on two separate days.

An A1c test should be performed in a laboratory using a method that is certified by the National Glycohemoglobin Standardization Program (NGSP) and standardized to the Diabetes Control and Complications Trial (DCCT) assay.

Normal Pre-diabetes Diabetes
Source: American Diabetes Association 2010
Fasting Glucose Test Less than 100 100-125 126 or higher
Random (anytime) Glucose Test Less than 140 140-199 200 or higher
A1c Test Less than 5.6% 5.7 - 6.4% 6.5% or higher
References

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This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 1/29/2013...#11644