Diabetes: An Overview

Reviewed by Sharon Denny, MS, RDN
Fruit and Vegetables - Diabetes: An Overview


When you hear "diabetes," most immediately think about blood sugar. People with diabetes have a higher than normal level of glucose in their blood. This can be caused by too little insulin being produced in the pancreas or the body not accepting or using the insulin it produces, or a combination of both. Managing diabetes is possible by working with a health care team to develop an individual plan that includes appropriate medical care, a healthy eating plan and physical activity.

The American Diabetes Association estimates 29.1 million Americans of all ages have diabetes — and many more have it but have never been diagnosed — so it is not unusual that almost everyone knows someone who has diabetes. The most common form of diabetes is Type 2. This form of diabetes develops slowly and over time, and it is becoming more common in Americans because of excess weight gain. Diabetes is a concern because it increases the risk of having a heart attack, stroke and kidney, eye and nerve damage.

The causes of diabetes are complex and still not fully known. Sometimes diabetes is triggered by genetics, illness, being overweight or simply getting older. Although food doesn't cause diabetes, it is part of the strategy for managing the disease.

Insulin and Glucose: The Relationship

Understanding diabetes begins with the relationship between insulin and glucose. Insulin is responsible for letting glucose pass into the cells and allowing the body use and store this energy.

In Type 2 diabetes, the pancreas makes insulin, but either it does not make enough of it or the body's cells don't use the insulin it makes. When glucose cannot get into the cells, it builds up in the blood. High glucose levels are commonly referred to as having high blood sugar. High blood sugar levels circulate through the body, damaging cells along the way.

Signs, Symptoms and Testing

Diabetes has many signs and symptoms including going to the bathroom frequently, being unusually thirsty, losing weight, feeling tired, irritability, blurred vision, frequent illness or infection and poor circulation such as tingling or numbness in the feet or hands.

Anyone exhibiting these symptoms should see a doctor immediately. Only a trained physician can confirm diabetes, with a diagnosis most likely occurring through one or more of the following tests:

  • Fasting Plasma Glucose: The amount of glucose in a sample of blood taken when a person is fasting (not eating anything for eight to 12 hours; usually overnight).
  • HgA1C: This measures a person's average blood glucose range over the past two to three months. This test shows the amount of glucose that sticks to the red blood cell (hemoglobin; Hg).
  • Oral Glucose Tolerance Test: Results of this test are compared with standard non-diabetic results and show how the body uses glucose over time. This test is performed by a health care professional after an overnight fast. A blood sample is taken, the patient drinks a high-glucose beverage and then a blood sample is taken two hours later.

Once diagnosed, overall goals for managing diabetes include:

  • Keeping blood glucose levels within normal range or as close to normal as possible, which can prevent or reduce complications.
  • Reducing risk of heart disease and stroke, since people with diabetes are at risk for both.
  • Keeping blood pressure in normal ranges, working to get healthy cholesterol levels and adopting a reasonable diet and lifestyle that are enjoyable in order to prevent, or at least slow, medical complications.

Managing Blood Glucose Levels

Persons with diabetes need to keep their blood glucose levels within a healthy range. The American Diabetes Association recommends the following range:

  • 80 to 130 mg/dl (before a meal)
  • <180 mg/dl (1 to 2 hours after beginning a meal)
  • HgA1c 7% (average glucose over 3 months)

For some people, medication or insulin injections are needed to help manage the relationship between glucose and insulin. However, action can be taken to control blood glucose levels including eating right, getting physical activity and weight management.

For more information on diagnosing diabetes, common terms and medical information, visit the American Diabetes Association.

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