Digestive Health: Fiber
What is fiber?
Fiber is a part of plant-based foods. There are two types of fiber:
- Insoluble fiber or “roughage,” is found in fruit and vegetable skins and in the bran layer of whole wheat.
- Soluble fiber, forms a gel in water. Good sources include citrus fruit, barley, oatmeal, oat bran, and dried peas and beans (legumes).
What does fiber do?
Insoluble fiber absorbs water in the colon that softens and increases the bulk of the stool. This action helps relieve constipation and helps prevent colon disease and hemorrhoids.
Water-soluble fiber can help you lower your blood cholesterol and glucose (sugar) levels. Fruits, dried peas and beans, barley, rolled oats and oat bran are good foods to add to a low cholesterol diet, and can help people with diabetes improve their blood sugar.
All types of fiber can help you lose weight. Fiber is not digested, so it does not add extra calories to your diet. The added bulk helps you feel full with less food. Since foods with fiber take longer to chew, they also help you slow the pace of your meals.
Can I eat too much fiber?
Fiber is just one part of a healthy diet. Fiber can bind with certain vitamins and minerals and this limits their absorption into your body. If you eat a balanced diet, this effect is not great enough to cause concern. Even vegetarians, whose diets are very high in fiber, have normal vitamin and mineral levels.
Do I need to take a fiber supplement?
There is no need for you to take fiber pills or powders, unless recommended by your health care provider. Eating a variety of fiber foods should provide enough fiber and at the same time supply necessary vitamins and minerals.
How should I increase the fiber of my diet?
Each day eat at least 5 servings of fresh or cooked vegetables and fruits and at least 3 servings of whole grain products. The goal for daily fiber intake is 25-35 grams.
It’s best to slowly increase the amount of fiber in your diet over several weeks. This prevents problems with stomachaches, bloating, gas, and diarrhea.
Fiber and water work together to help improve bowel function. Be sure to drink eight to ten (8 ounce) glasses of fluid daily. Without enough fluid, a high fiber diet can be constipating since fiber absorbs large amounts of water.
Compare these two meal plans. Which one is most like your diet?
Menu low in fiber
Breakfast
Orange juice
Scrambled eggs
White toast
Margarine
Milk
Lunch
Tomato soup
½ tuna salad sandwich on white bread
Fudge brownie
Milk
Dinner
Baked chicken
Buttered noodles
Green beans
Butterscotch pudding
Milk
Menu high in fiber
Breakfast
Fresh whole orange
Scrambled eggs
Oat bran muffin
Margarine
Milk
Lunch
Minestrone soup
½ tuna salad sandwich on wheat bread
Fresh strawberries
Milk
Dinner
Chicken/broccoli stir-fry on brown rice
Fresh fruit salad
Apple crisp
Milk
Fruits
Fruits are grouped by the amount of fiber in a serving. The list refers to fresh fruits unless noted. The serving size is ½ cup unless noted.
High Fiber Fruits
Over 3 grams fiber per serving
Prunes, 5 dried |
3.1 |
Raisins |
3.2 |
Apple, 1 large unpeeled |
3.8 |
Dates, 3 dried |
4.3 |
Pear, 1 unpeeled |
4.7 |
Blackberries |
4.9 |
2.1 - 3.0 grams fiber per serving
Blueberries |
2.1 |
Orange, 1 medium |
2.2 |
Apple, 1g, peeled |
2.6 |
Raspberries |
2.6 |
Low Fiber Fruits
2.0 grams fiber per serving
Apricots, 4 halves Fresh, dried or canned |
1.3 |
Strawberries |
1.4 |
Peach, peeled |
1.4 |
Cherries, sweet |
1.5 |
Mango |
1.5 |
Applesauce, cooked |
1.5 |
Tangerine, 1 medium |
1.5 |
Nectarine, 2-1/2” |
1.6 |
Pears, 2 peeled halves |
1.7 |
Banana (8-3/4” long) |
1.9 |
Under 1 gram fiber per serving
Fruit juices |
.2 |
Mandarin oranges |
.3 |
Watermelon |
.3 |
Grapefruit sections |
.4 |
Olives, 5 green or black |
.4 |
Friar & prune plum |
.5 |
Honeydew melon |
.5 |
Grapes, green or red |
.5 |
Cantaloupe |
.6 |
Pineapple |
.7 |
Cherries, sour canned |
.8 |
Fruit cocktail, canned |
.9 |
Vegetables
Vegetables are grouped by the amount of fiber in a serving. A serving size is ½ cup of fresh vegetable unless otherwise noted.
Note: The amount of fiber in a cooked versus fresh vegetable (e.g. mushrooms) is not always the same. There is often a greater volume of vegetable in a ½ cup cooked portion compared to a ½ cup raw portion. Therefore, there is more fiber in 1/2 cup cooked mushrooms or spinach compared to ½ cup raw. Cooking does not decrease the fiber content of a food.
High Fiber Vegetables
Over 3 grams fiber per serving
Brussels sprouts |
3.1 |
Pumpkin, canned |
3.5 |
Potato with skin, 1 large |
4.7 |
Lima beans, cooked |
5.1 |
Pork and beans, cooked |
5.6 |
Kidney beans, cooked |
6.6 |
2.1 - 3.0 grams fiber per serving
Mushrooms, canned |
2.0 |
Carrot, 1 large |
2.1 |
Turnip greens, cooked |
2.1
|
Rhubarb, cooked |
2.2 |
Spinach, cooked |
2.3 |
Spinach, raw, 2 cups |
2.3 |
Broccoli |
2.7 |
Green peas |
2.8 |
Low Fiber Vegetables
2.0 grams fiber per serving
Peppers |
1.1 |
Celery |
1.1 |
Onions |
1.3 |
Green beans |
1.4 |
Cauliflower |
1.4 |
Asparagus |
1.8 |
Sweet potatoes, Peeled |
1.9 |
Under 1 gram fiber per serving
Mushrooms, fresh |
.3 |
Lettuce, iceberg/leaf |
.4 |
Chinese cabbage |
.4 |
Cucumber, peeled |
.5 |
Radish |
.6 |
Zucchini |
.7 |
Cabbage, raw |
.7 |
Bean sprouts |
.8 |
Tomato, ½ c. or 2 ½ " fresh |
.8 |
Potatoes, peeled |
.9 |
Bread, Cereal, Rice, and Pasta
The Nutrition Facts on food labels will list fiber content.
High Fiber Grains
Bran, includes oat and wheat bran
Brown rice
Buckwheat
Oatmeal
Foods made with whole oats
Peanut flour
Rye flour
Soybean flour
Wild rice
Whole wheat flour
Qunioa
Cereals
Read food labels and choose high fiber cereals. Cereals that contain 5 grams of fiber or more per serving are high fiber cereals.
Try this muffin recipe for a tasty way to add fiber.
Orange Bran Flax Muffins
Makes 18 muffins
Serving size 1 muffin
1 cup whole flax seed
1 1/2 c oat bran
1 c all-purpose flour
1 cup natural bran (not the cereal)
1 T baking powder
1/2 t salt
2 whole orange (washed, quartered, seeded)
1 c brown sugar
1 cup buttermilk or diluted plain yogurt (6 oz diluted with milk to make 8 oz)
1/3 c canola oil
2 eggs
1 t baking soda
1 c currants or mini chocolate chips
In a blender, whiz whole flax seed until finely ground (once ground, use right away or store in refrigerator or freezer, as this is a natural food that is perishable).
In a large bowl, combine all the dry ingredients (flax through salt).
In the blender, combine oranges, brown sugar, milk/yogurt, oil, eggs and baking soda. This step can also be done in a food processor, but it will over-flow, so process half at a time.
Pour wet ingredients into dry ingredients and mix until just blended. Stir in currants or chocolate chips.
Fill paper-lined muffin cups almost to the top. Bake in preheated 375 degree oven for 18-20 minutes, or until toothpick comes out clean from the center.
Cool 5 minutes before transferring to cooling rack.
One serving (1 muffin) = 205 calories, 31 g carbohydrate, 6 g protein, 9 g fat, 6 g fiber
(For diabetics: 2 bread exchanges, 2 fat exchange)
More Information
Processed fiber is now being added to many foods so “good source of fiber” can be on the label of everything from bars to yogurt. The majority of the research on the benefits of fiber used naturally-occurring fiber. Therefore, nutritionists advise you to eat more legumes, whole grains, fruits and vegetables, not only for the unprocessed fiber, but for all the additional nutrients they provide.
Fiber in foods contain a mixture of both soluble and insoluble fiber. Insoluble fiber includes cellulose, hemicellulose and lignin. Insoluble fiber is in foods such as whole grain breads and cereals, vegetables and seeds.
Soluble fiber includes pectins, gums, and mucilages. Soluble fiber is in foods such as fruit, barley, oatmeal, oat bran and legumes. Although these foods are high in soluble fiber, no food is more than about 40% soluble fiber.
Appearance, texture, or color does not reveal the fiber content of foods. For instance, ½ cup avocado (which has a very smooth texture) contains 5 grams of fiber, while ½ cup of cabbage has less than 1 gram. Food labels are a good resource for fiber content.
Teach Back:
What is the most importan thing you learned from this handout?
What changes will you make in your diet/lifestyle, based on what you learned today?
If you are a UW Health patient and have more questions, please contact UW Health at one of the phone numbers listed below.
UW Digestive Health Center |
UW Health East Clinic |
UW Health West Clinic |
UW Medical Foundation |
The information provided should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Any duplication or distribution of the information contained herein is strictly prohibited.
Last Updated: 05/23/2013
Copyright © 01/22/2013 University of Wisconsin Hospitals and Clinics Authority. All rights reserved. Produced by the Department of Nursing. HF#190
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