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The Facts on Fiber

By Suzanne Dixon, M.P.H., M.S., R.D.
Nutrition Specialist

Q What is fiber?

A Fiber is found in plant foods, such as fruits, vegetables, whole grains and legumes (beans, chickpeas, lentils, etc). Fiber is the part of the plant that our bodies CANNOT digest. That means, our bodies don't break down fiber and don't use it for energy or calories.

Q If my body doesn't digest fiber, why do I need it?

A Fiber is very important and helps our bodies stay healthy. Fiber helps our digestive tracts (stomach and intestines) work properly. Fiber also helps our bodies process cholesterol and hormones.

Q How can fiber do both of these jobs? They seem very different.

A Fiber can do both of these jobs because there are two different kinds of fiber: SOLUBLE and INSOLUBLE fiber.

Q How can I tell the difference between soluble and insoluble fiber?

A Picture in your mind what a food looks like when it gets wet, for example with milk or water.

Soluble fiber is the type of fiber that gets very gooey and sticky when it gets wet. The best example of soluble fiber is oatmeal. Picture how oatmeal looks and feels after it gets wet. It feels sticky and gooey because it contains a lot of SOLUBLE fiber.

Insoluble fiber is the type of fiber that doesn't change at all when it gets wet. A good example of insoluble fiber is the skin of an apple. If you put an apple skin in water, 3 hours later it still looks like an apple skin. Tough, stringy pieces in celery are insoluble fiber too. An apple skin or piece of celery contains a lot of INSOLUBLE fiber and this is why it doesn't change when it gets wet.

Q What does soluble fiber do for me?

A Soluble fiber does a lot of good things for our bodies, such as helping to lower cholesterol. So, if you have high cholesterol, eating a lot of soluble fiber may help you bring your blood cholesterol levels down.

Also, if you are going through cancer treatment and have diarrhea, soluble fiber can help minimize your diarrhea. Choose foods from the soluble fiber list below; this may help slow your diarrhea down.

Q What does insoluble fiber do for me?

A Insoluble fiber also does a lot of good things for our bodies, such as helping eliminate waste more quickly. Insoluble fiber helps prevent constipation. If you are going through cancer treatment, you may be taking medications that cause constipation. These include medications that help with nausea and pain. If you are constipated, try eating foods with a lot of insoluble fiber (choose from the list below). Just be sure to drink a lot of water with these foods. This will help cut down on gas production and move the waste through your body more quickly.

Q How much soluble and insoluble fiber should I eat every day?

A For good health, experts recommend that we eat at least 25 to 35 grams of fiber every day. This fiber should be a combination of both soluble and insoluble fiber. Most Americans don't even come close to eating this much fiber. Most people eat about 8 to 12 grams every day. That's less than half of the fiber we should be eating!

Start meeting your fiber goal today by choosing a wide variety of whole grains, fruits, vegetables and legumes (beans, lentils, chickpeas, etc.) as part of every meal and snack.

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