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(Lesson 10) Dietary Fiber


Dietary Fiber - Nature's Little Mermaid

Would you like to know why dietary fiber is called nature's little mermaid as given in the title of this lesson? See if you can find the answer. But first, let's talk about what we will cover in this lesson. Have you ever been constipated? Did you know that there is something in food that helps with that problem and offers other health benefits as well? It's called dietary fiber. In this lesson, we will learn what dietary fiber is, what foods are good sources, what the health benefits are, how much dietary fiber we need and tasty ways of getting more fiber into our diets.

What You Will Learn

  • The different types of dietary fiber (soluble and insoluble) and the benefits of each.
  • Medical problems that can result from too little dietary fiber.
  • What foods and food groups are good sources of dietary fiber.
  • The amount of dietary fiber recommended each day.


The USDA Department of Agriculture developed a Food Guide to help you see what foods you and your family should eat each day for good health. Foods that make similar nutritional contributions are grouped into basic food groups. The Guide also lets you know how many servings of each food group are needed each day.

Eat some food from each of the basic food groups in the Guide, and eat the recommended number of servings.


Look at the Food Guide plan and write down the name of each of the basic food groups. Write down how many servings you need each day.

Question 1:

What is dietary fiber?

Dietary fiber is the non-digestible part of plants that adds bulk to your diet. It is found only in foods that come from plants. Fiber is found mainly in the cell walls, providing the structure and shape of the plant. Fiber gives celery its rigid stalk and gives turnip greens the strong stem that holds up its leaves. Fiber is the part of whole grains, fruits, vegetables, beans, nuts and seeds that we cannot digest. Since it can't be digested and absorbed in our body, fiber is really not a nutrient. It's called a non-nutrient part of plant foods.

Question 2:

How fibers are grouped and why is that important?

There are two kinds of dietary fiber. They are not all alike and they keep you healthy in different ways. Fiber is grouped as being either water soluble or water insoluble. This means some fibers dissolve in water and some don't. You need to eat foods that give you both kinds of fiber. Think of fiber as being a mermaid swimming in water all the way down your gastrointestinal tract. Since fiber cannot be digested, it is carried all the way through your gastrointestinal tract. Our little mermaid, fiber, is attractive. It attracts water and also some of the bad cholesterol, removing them from your body.

Attracting water helps stools to be soft and easy to eliminate. If you don't have enough water, stools are drier and harder, making using the bathroom difficult and painful. Fiber attracting some of the bad cholesterol is a great way to get rid of the bad guy. If the bad cholesterol builds up in our body, it increases our risk of heart disease. Eating a mixture of dietary fibers helps both with potty problems and with decreasing the risk of heart disease. The more fiber you get from the foods you eat, the more bowel movements you have. The more water fiber absorbs, the easier it is for you to have bowel movements. Drinking plenty of water and other fluids is important to help fiber do its job!

It's Your turn:

  • Write down the names of two kinds of dietary fiber and what they mean.
  • Tell someone why it is important to drink plenty of water and other fluids

Insoluble fiber doesn't dissolve in water.

Have you ever had trouble with constipation or hemorrhoids? Have you been in so much pain that you had to grip the side of the commode seat with your fist when you were trying to have a bowel movement? If so, you need more insoluble fiber and water in your diet. Insoluble fiber helps prevent painful constipation and hemorrhoid problems.

Water insoluble fiber refers to the rigid material that gives structure to the leaves, stems and seeds of plants. It is also called roughage. Make a fist with your hand. Name some vegetables and grains that you can hold in your fist to create a fiber bouquet. These would be examples of plant foods that give us insoluble fiber. Did you name broccoli, celery, turnip greens or other deep leafy green vegetables, Chinese cabbage, okra, carrots, green beans, squash and wheat? The insoluble fiber in these plant foods gives structure to plant leaves, stems and seeds.

Insoluble fiber is concentrated in the protective outer layers of whole grains, called the bran layers. Wheat bran, bran and whole-grain cereals and cereal products are excellent sources of insoluble fiber. Select cereals that have the word bran in their names for the best sources of bran.

Water insoluble fiber is also concentrated in stalks, seeds and skins or peelings of fruits and vegetables. Examples include skins of apples, pumpkin or sunflower seeds and celery stalks.

Insoluble fiber is most often found in whole-grain products such as whole-wheat bread. Wheat bran seems to be one of the most effective stool-softening fibers. When eating foods that are good sources of water insoluble fiber, drink plenty of water and other fluids. This increases bulk, frequency and ease of bowel movements. Insoluble fiber tends to speed the movement of the solid wastes through the lower part of the intestinal tract, increasing the frequency of bowel movements. If you don't have regular bowel movements or if you may go days without having a bowel movement, you need to include more insoluble fiber and water in your food intake. Insoluble fiber also helps to satisfy appetite by creating a full feeling.

Memory joggers:

Think and form a picture in your mind about the following words: Insoluble fiber - Potty - Fist (Holding edge of commode, Holding plant foods)


IFP - IF for insoluble fiber. Just close the F to make a P. P for Potty. Insoluble Fiber Prevents Potty Problems.

Soluble fiber dissolves in water and is broken down by bacteria in your colon.

It is found in dry beans and peas, in some cereals such as oats and barley and in some fruits and vegetables. Water-soluble fiber such as oat bran, oatmeal and the fiber of apples helps lower blood cholesterol levels and helps regulate the body's use of sugar.

Visit the Quaker Oats Canada Web site to see ways of getting more water soluble fiber from oats into your diet:

Click on the recipe of the week tab.

Also click on the recipe archive tab to see many different recipes featuring oats. Note that the recipes include metric as well as standard measurements.

Review of Food Guide:


What foods give us fiber, plant or animal foods or both plant and animal foods?

Which food groups are good sources of dietary fiber?

Where in the Pyramid are they located?

How many servings do you need each day?

We obtain dietary fiber from plant foods. The best sources of dietary fiber are vegetables, fruits, whole-grains, such as whole grain breads and cereals, and nuts and seeds.

We need to eat a variety of foods as recommended by the Food Guide, including foods that are good sources of complex carbohydrates and fiber. Most food sources of complex carbohydrates are found in the food groups at the lower two levels of the Food Guide. The bread and cereals group is on the first or bottom level and the fruits and vegetables groups are on the second level, going up the Pyramid..

The Food Guide recommends that we eat more than six servings a day of grain-based foods like bread, cereal, pasta and rice. Be sure to select whole-grains for at least three of your daily complex carbohydrate servings. A study of 30,000 women ages 55 to 60 found that they were 30 % less likely to die of a heart attack if they ate at least three of the six servings of breads and cereals as whole-grain instead of as refined grain foods. Americans eat only 5% of grain foods as whole-grain foods.

We need to increase complex carbohydrate and high fiber foods in our diets:

  • Eat 9 servings of fruits and vegetables, including legumes, daily.
  • Eat six or more servings of grain products daily.


How much dietary fiber do you need?

The National Cancer Institute recommends 20 to 30 grams of dietary fiber per day with an upper limit of 35 grams. The % Daily Value for dietary fiber on the nutrition label is based on 12 1/2 grams of dietary fiber per 1,000 calories or 25 grams of fiber for a 2,000 calorie diet.

Last Updated: 8/24/2011 12:39:44 PM
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