Fiber

Introduction
Why should I eat more fiber?
How can I get more fiber in my diet?
Start Slowly
Fiber and Colon Cancer
Fiber and Heart Disease
Fiber and Type 2 Diabetes
Fiber and constipation

Fiber is a substance in plants. Dietary fiber is the kind you eat. It is in fruits, vegetables and grains. It is the part of the plant that your body can't digest. Yet it is an important part of a healthy diet. It adds bulk to your diet and makes you feel full faster, helping you control your weight. Fiber helps digestion and helps prevent constipation.

You can get fiber from whole grains, beans, nuts, fruits and vegetables. You should add fiber to your diet slowly. Increasing dietary fiber too quickly can lead to gas, bloating and cramps.

Foods that are high in fiber can help in the treatment of constipation, hemorrhoids, diverticulitis and irritable bowel syndrome. Dietary fiber may also help lower your cholesterol, and reduce your risk of heart disease, diabetes and certain types of cancer.

• Eat at least 4 1/2 cups of fruits and vegetables each day. Fruits and vegetables that are high in fiber include:

Carrots Apples Oranges Broccoli Cauliflower Berries

Beans Pears Brussels sprouts Green peas Figs Prunes



• Replace white bread with whole-grain breads and cereals. Eat brown rice instead of white rice. Eat more of the following foods:
• Bran muffins
• Oatmeal
• Multiple-grain cereals, cooked or dry
• Brown rice
• Popcorn
• 100% Whole-wheat bread
• Eat bran cereal for breakfast. Check labels on the packages for the amounts of dietary fiber in each brand. Some cereals may have less fiber than you think.
• Add 1/4 cup of wheat bran (miller's bran) to foods such as cooked cereal or applesauce or meat loaf.
• Eat cooked beans each week

When you first add fiber to your diet you may notice bloating, cramping or gas. But you can prevent this by making small changes in your diet over a period of time. Start with one of the changes listed above, then wait several days to a week before making another. If one change doesn't seem to work for you, try a different one.

Be sure to drink more fluids when you increase the amount of fiber you eat. Liquids help your body digest fiber better. Try to drink 8 glasses of no- or low-calorie beverages, such as water, unsweetened tea or diet soda each day.

For years, Americans have been told to consume a high-fiber diet to lower the risk of colon cancer - mainly on the basis of results from relatively small studies. Larger and better-designed studies have failed to show a link between fiber and colon cancer. One of these - a Harvard study that followed over 80,000 female nurses for 16 years - found that dietary fiber was not strongly associated with a reduced risk for either colon cancer or polyps (a precursor to colon cancer).

But just because fiber plays little role in preventing colon cancer doesn't mean you should abandon a high-fiber diet. As explained below, fiber provides many other benefits.

In the United States, coronary heart disease is a leading cause of death for both men and women. This disease is characterized by a buildup of cholesterol-filled plaque in the coronary arteries - the arteries that feed the heart. This causes them to become hard and narrow, a process referred to as atherosclerosis. Total blockage of a coronary artery produces a heart attack.

Fiber intake has also been linked with the metabolic syndrome, a constellation of factors that increases the chances of developing heart disease and diabetes. These factors include high blood pressure, high insulin levels, excess weight (especially around the abdomen), high levels of triglycerides, the body's main fat-carrying particle, and low levels of HDL (good) cholesterol. Several studies suggest that higher intake of fiber may somehow ward off this increasingly common syndrome.

Type 2 diabetes is the most common form of diabetes. It is characterized by sustained high blood sugar levels. It tends to develop when the body can no longer produce enough of the hormone insulin to lower blood sugar to normal levels or cannot properly use the insulin that it does produce. (For more information on type 2 diabetes, see the Carbohydrates and Diabetes pages.)

There are several important factors that may help lower your risk for type 2 diabetes, such as maintaining a healthy weight, being physically active, and not smoking. Researchers are also trying to pinpoint any relevant dietary factors, one of which seems to be a high-fiber diet. The studies of male health professionals and female nurses both found that a diet high in cereal fiber was linked to a lower risk of type 2 diabetes.

Foods that have a high glycemic index include potatoes, refined foods such as white bread, white rice, refined cereals (corn flakes, Cheerios), white spaghetti, and sugar. Foods with a low glycemic index do not raise blood sugar levels as quickly and, therefore, are associated with a lower risk of type 2 diabetes. Low glycemic index foods include legumes, whole fruits, oats, bran, and whole-grain cereals. For more information on glycemic index, see the Carbohydrates page.

Constipation is the most common gastrointestinal complaint in the United States and is of particular concern to the elderly. The gastrointestinal tract is highly sensitive to dietary fiber, and consumption of fiber seems to relieve and prevent constipation. The fiber in wheat bran and oat bran seems to be more effective than similar amounts of fiber from fruits and vegetables. Experts recommend increasing fiber intake gradually rather than suddenly. The intake of beverages should also be increased, as fiber absorbs water.