• Highlights
• Introduction
• Causes
• Risk Factors
• Symptoms
• Emergency Complications
• Screening Tests
• Treatment
• Lifestyle Changes
• Medications
• Long-Term Complications
• Resources
• References

Diabetes - type 2

Description

An in-depth report on the causes, diagnosis, treatment, and prevention of type 2 diabetes.

Alternative Names

Type 2 diabetes; Maturity onset diabetes; Noninsulin-dependent diabetes

Lifestyle Changes

A simple heart-healthy diet with weight control and exercise may be sufficient for some people with type 2 diabetes. Some patients may be able to control their blood sugar with lifestyle measures and not need medication. Even for patients who do need to take drugs, lifestyle plays an essential role in controlling diabetes. Lifestyle changes can be difficult to initiate and sustain, however. Patients should surround themselves with a solid network of doctors, dietitians, family, and friends who understand both their condition and their needs.

Heart-Healthy Diet

Although there are many major dietary approaches for protecting health, experts generally agree on the following recommendations for heart protection:

• Choose fiber-rich food (whole grains, legumes, nuts) as the main source of carbohydrates, along with a high intake of fresh fruits and vegetables. Walnuts in particular have cholesterol-lowering properties and are a good source of antioxidants and alpha-linolenic acid.
• Avoid saturated fats (found mostly in animal products) and trans fatty acids (found in hydrogenated fats and many commercial products and fast foods). Choose unsaturated fats (particularly omega-3 fatty acids found in vegetable and fish oils).
• In selecting proteins, choose soy protein, poultry, and fish over meat. A 2006 study found that soy does not help improve cholesterol. However, experts still recommend it as a heart healthy food choice.
• Weight control, quitting smoking, and exercise are essential companions of any diet program.

[For detailed information, see In-Depth Report #43: Heart-healthy diet.]

Diabetes Diet

There is no such thing as a single diabetes diet. Patients should meet with a professional dietitian to plan an individualized diet within the general guidelines that takes into consideration their own health needs.

Healthy eating habits along with good control of blood glucose are the basic goals, and several good dietary methods are available to meet them. General dietary guidelines for diabetes recommend:

• Carbohydrates should provide 45 – 65% of total daily calories. The type and amount of carbohydrate are both important. Best choices are vegetables, fruits, beans, and whole grains. These foods are also high in fiber. Patients with diabetes should monitor their carbohydrate intake either through carbohydrate counting or meal planning exchange lists.
• Fats should provide 25 – 35% of daily calories. Monounsaturated (olive, peanut, canola oils; avocados; nuts) and omega-3 polyunsaturated (fish, flaxseed oil, walnuts) fats are the best types. Limit saturated fat (red meat, butter) to less than 7% of daily calories. Choose nonfat or low-fat dairy instead of whole milk products. Limit trans-fats (hydrogenated fat found in snack foods, fried foods, commercially baked goods) to less than 1% of total calories.
• Protein should provide 12 – 20% of daily calories, although this may vary depending on a patient’s individual health requirements. Patients with kidney disease should limit protein intake to less than 10% of calories. Fish, soy, and poultry are better protein choices than red meat.

[For detailed information, including diabetic exchange lists and carbohydrate counting, see In-Depth Report #42: Diabetes diet.]

Weight Loss

Being overweight is the number one risk factor for type 2 diabetes. Even modest weight loss can help prevent type 2 diabetes from developing. It can also help control or even stop progression of type 2 diabetes in people with the condition and reduce risk factors for heart disease. Patients should aim to lose weight if their body mass index (BMI) is 25 – 29 (overweight) or higher (obese).

The American Diabetes Association recommends that patients aim for a small but consistent weight loss of 1 to 2 pounds per week. Most patients should follow a diet that supplies at least 1,000–1,200 kcal/day for women and 1,200–1,600 kcal/day for men.

Unfortunately, not only is weight loss difficult to sustain, but many of the oral medications used in type 2 diabetes cause weight gain as a side effect. For obese patients who cannot control weight using dietary measures alone, weight-loss drugs, such as orlistat (Xenical) or sibutramine (Meridia), may be helpful. Orlistat may have specific benefits for people with diabetes. It may not only help achieve weight but also improve glucose, cholesterol, and lipid levels. A new weight-loss drug called rimonabant (Acomplia) has been approved in Europe and is being considered for approval in the United States. [For detailed information, see In-Depth Report #53: Obesity.]

Exercise

Sedentary habits, especially TV watching, are associated with significantly higher risks for obesity and type 2 diabetes. Regular exercise, even of moderate intensity (such as brisk walking), improves insulin sensitivity and may play a significant role in preventing type 2 diabetes -- regardless of weight loss. An important study reported a 58% lower risk for type 2 diabetes in adults who performed moderate exercise for as little as 2.5 hours a week.

Aerobic Exercise . Aerobic exercise has significant and particular benefits for people with diabetes. Regular aerobic exercise, even of moderate intensity, improves insulin sensitivity. People with diabetes are at particular risk for heart disease, so the heart-protective effects of aerobic exercise are especially important. Moderate exercise protects the heart in people with type 2 diabetes, even if they have no risk factors for heart disease other than diabetes itself. (In general, patients with diabetes should aim for a heart rate target of 55 - 75% of their maximum heart rate when exercising.)

Strength Training . Strength training, which increases muscle and reduces fat, may also be helpful for people with diabetes.

Exercise Precautions . The following are precautions for all people with diabetes, both type 1 and type 2:

• Because people with diabetes are at higher than average risk for heart disease, they should always check with their doctors before undertaking vigorous exercise. For fastest results, frequent high-intensity (not high-impact) exercises are best for people who are cleared by their doctors. For people who have been sedentary or have other medical problems, lower-intensity exercises are recommended.
• Strenuous strength training or high-impact exercise is not recommended for people with uncontrolled diabetes. Such exercises can strain weakened blood vessels in the eyes of patients with retinopathy. High-impact exercise may also injure blood vessels in the feet.

Patients who are taking medications that lower blood glucose, particularly insulin, should take special precautions before embarking on a workout program:

• Monitor glucose levels before, during, and after workouts (glucose levels swing dramatically during exercise)
• Avoid exercise if glucose levels are above 300 mg/dL or under 100 mg/dL
• Inject insulin in sites away from the muscles used during exercise; this can help avoid hypoglycemia
• Drink plenty of fluids before and during exercise; avoid alcohol, which increases the risk of hypoglycemia
• Insulin-dependent athletes may need to decrease insulin doses or take in more carbohydrates prior to exercise, but may need to take an extra dose of insulin after exercise (stress hormones released during exercise may increase blood glucose levels)
• Wear good, protective footwear to help avoid injuries and wounds to the feet
• Some blood pressure drugs can interfere with exercise capacity. Patients who use blood pressure medication should consult their doctors on how to balance medications and exercise. Patients with high blood pressure should also aim to breathe as normally as possible during exercise. Holding the breath can increase blood pressure.

[For more information, see In-Depth Report #29: Exercise.]

Monitoring Glucose (Blood Sugar) and Hemoglobin A1C

According to the American Diabetes Association, people with diabetes should aim for preprandial (before eating) plasma glucose levels of 90 to 130 mg/dL and postprandial (after eating) plasma glucose levels less than 180 mg/dL. Hemoglobin A1C levels should be less than 7%.

Measuring Blood Glucose. In patients being treated with insulin or insulin-producing or sensitizing drugs, it is important to monitor blood glucose levels carefully to avoid hypoglycemia. Different goals may be required for specific individuals, including pregnant women, very old and very young people, and those with accompanying serious medical conditions.

Blood glucose levels are generally more stable in type 2 diabetes than in type 1, so experts usually recommend measuring blood levels only once or twice a day. For patients who have become insulin-dependent, more intensive monitoring is necessary. Usually, a drop of blood obtained by pricking the finger is applied to a chemically treated strip. The glucose level is read on a standard meter or a small, portable digital display device.

Measuring Hemoglobin A1C. Hemoglobin A1c (HbA1c or HA1c), also called glycated hemoglobin, is measured periodically to determine the average blood-sugar level over the life span of the red blood cell, which is about 8 to 10 weeks. Home tests (DRx, Metrika A1c Now) are available for measuring HA1c that may allow even better monitoring of glucose levels. Patients should keep a chart of their HA1c levels to track any changes that may occur over time.

Improving Sleep

Some research suggests that not getting enough sleep may impair insulin use and increase the risk for obesity. More research is needed, but it is always wise to improve sleep habits.

• Review Date: 7/15/2006
• Reviewed By: Harvey Simon, M.D., Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital

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