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Dietary fiber is the part of a plant that cannot be digested
by the body. Just as there are many types of plants, there are
also many types of fiber. Some fibers, such as oat bran, are
soluble in water and form a gelatinous bulk that can lower
cholesterol. Other fibers, such as wheat bran, are insoluble and
add bulk to the stool. Both are important and provide
benefits.
The Function of the Large Intestine
The principal function of the large intestine (colon) is to
remove excess water from food wastes passing into it from the
small intestine. When food passes through the large intestine too
quickly, not enough water is absorbed by the intestine, and
diarrhea results. In contrast, if waste material is passed too
slowly, too much water is absorbed. This results in hard stools
and constipation, often leading to straining.
The Importance of Dietary Fiber
Fiber, also called roughage or bulk, is necessary to promote
the wavelike contractions that move food through the intestine.
High fiber foods expand the inside walls of the colon, easing the
passage of waste. As fiber passes through the intestine
undigested, it absorbs large amounts of water, resulting in
softer and bulkier stools.
Rural Africans digest and eliminate the foods they eat in
one-third the time it takes people who live in Western cultures.
The rural African diet is rich in fiber. This speeds up the time
required to digest food and expel wastes. It is believed this
helps sweep out harmful substances before they can cause problems
in the body. In fact, these rural people suffer less from many of
the digestive tract diseases that plague Western man, and it is
thought that this may be related to the nature of their diet.
A high-fiber diet causes a large, soft, bulky stool that
passes through the bowel more easily and quickly. This helps to
prevent, stop, or even reverse some digestive tract disorders. A
softer, larger stool helps prevent constipation and straining,
which can help avoid or relieve hemorrhoids. More bulk means less
pressure in the colon, and this is important in treating
irritable bowel syndrome and diverticulosis.
Most Americans eat only IO to 15 grams of fiber a day. The
recommended intake is 20 to 35 grams a day. High fiber foods,
such as fruits and vegetables, also tend to be low in calories,
so they should not cause weight gain. Fiber pills generally
should be avoided. They contain relatively little fiber and are
expensive. Fiber-containing foods and powdered fiber supplements
are better sources.
Fiber and Irritable Bowel Syndrome
Irritable bowel syndrome, sometimes called spastic colon or
IBS, is one of the most common disorders of the lower digestive
tract. There is no disease present in irritable bowel syndrome.
However, its symptoms can resemble other disorders. The symptoms
of IBS are constipation, diarrhea (or both alternately),
abdominal pain, cramping and spasms. Acute episodes can be
triggered by emotional tension and anxiety, poor dietary habits,
and certain medications. Increased amounts of fiber in the diet
can help relieve symptoms of irritable bowel syndrome by
producing soft, bulky stools and by helping to normalize the time
the stool takes to pass through the colon. The increased bulk
also reduces the pressure necessary to push food waste through
the colon. This results in less discomfort. If irritable bowel
syndrome is not treated it may lead to diverticulosis of the
colon.
Fiber and Diverticulosis
Colon diverticulosis occurs when pockets or sacks bulge out
from the bowel wall. It is known that these diverticula occur
gradually over time and are due to excessive pressure or spasms
within the bowel. These pockets usually cause no problem, but
sometimes they can become infected (diverticulitis) or even break
open, causing abscess or peritonitis. A high-fiber diet may act
to increase the bulk in the stool, which reduces pressure within
the colon. By so doing, diverticula formation may be reduced or
even stopped.
Fiber and Cholesterol
As noted above, fiber generally is divided into two
categories. Insoluble fiber is found in wheat bran and in
celluloses from vegetables and fruits. Soluble fiber is commonly
found in oatmeal, oat bran (the best source), guar gum, psyllium
seed, fruit pectin and gum arabic. When mixed with water, it
produces a gelatinuous mucous gel. It, too, has bowel-regulating
effects. It also acts to lower blood cholesterol by binding with
the cholesterol in the intestine and carrying it away in the
stool. So, a high fiber diet should contain both types of
fiber.
Fiber and Cancer
Recent evidence seems to indicate that fiber, by itself, even
up to 25 grams a day, does not reduce the risk of colon or other
cancers. However, many high fiber foods are also very rich in
chemicals called antioxidants. These substances attack other
chemicals known as free radicals. Free radicals occur in the body
as a natural byproduct of metabolism. Yet, they can damage
surrounding cells and seem to be related to increased risk of
heart disease, macular degeneration (eye problems), and some
cancers such as prostate cancer. Hundreds of very potent
antioxidants occur in many fruits and vegetables which are also
high in fiber. Nature seems to have naturally put these two
substances together. Five portions of fruits and/or vegetables
are recommended each day. Select those that are rich in color
such as dark green, yellow, red, or orange.
Fiber and Whatever
What else may high fiber help? In many instances, the medical
evidence is soft or fragmentary. Yet the preponderance of
evidence is so overwhelming that high fiber foods can be
recommended for just about everyone. Other diseases that are or
may be benefited by high fiber foods are:
- Diabetes
- Bowel irregularity
- Constipation or diarrhea
- Macular degeneration
- Hiatus hernia
High Fiber Foods
High fiber foods can be found in most food groups. Different
types of food should be selected to get the benefits of them
all.
1. Legumes - Including kidney, pinto, navy, lima and baked
beans. The bean family excels in fiber, especially the soluble,
cholesterol-lowering type.
2. Whole Grains - Wheat bran and oat bran are present in a
variety of cereals and breads. The label should say that the
bread contains whole wheat or whole grain. Plain wheat bread may
lack the fiber. One cannot always tell by the color. Some
manufacturers artificially color bread brown to make it look more
wholesome.
3. Whole Fresh Fruits - The valuable pectin fiber is found in
the skin and pulp. Figs, prunes and raspberries have the highest
fiber content.
4. Cooked or Stewed Fruits - Prunes and applesauce are good
choices.
5. Green Leafy Vegetables - Lettuce, spinach, celery, and
broccoli are good examples.
6. Root Vegetables - Potatoes, turnips and carrots are all
excellent sources.
Since bran can cause rumbling intestinal gas and even some
mild cramping, it should be started in small amounts initially.
The amount can be increased as tolerance is acquired. The goal
should be 20 to 35 grams of fiber a day, which will usually
produce I to 2 soft, formed stools a day.
1. Drink plenty of liquids, including fruit or vegetable
juices and water.
2. Eat slowly and chew food thoroughly to allow the upper
digestive tract (esophagus, stomach and small intestine) to work
well. This may help prevent problems from developing in the lower
digestive tract.
3. Eat meals at regular intervals.
A Dietary Fiber Supplement May Be Helpful
Some people have trouble tolerating too many high fiber foods
in the diet. Stool softening and bulking agents are available
over the counter. These products are usually plant fiber that
absorbs water and produces the bulk necessary for the digestive
tract to perform naturally. Psyllium fiber is found in many
commercial products such as Metamucil, Per Diem and Konsyl. The
regular product contains a fair amount of sugar, so it may be
preferable to use the sugar-free products. Most pharmacies carry
a generic brand at significant cost savings. Citrucel
(hemicellulose) and Equilactin (polycarboxisal) are other bulking
agents that can be used. These fiber supplements, in conjunction
with foods, offer an easy way to reach the fiber goal of 20 to 35
grams per day.
Fiber Content of Foods
Goal - 20 to 35 grams per day
Common servings of foods containing dietary fiber are shown
below. A variety of foods should be chosen every day. Foods that
are good sources of fiber are typically low in fat and
calories.
Serving size followed by grams of dietary
fiber:
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| DIETARY FIBER CHART |
BREADS |
LEGUMES |
 |
1 med. bran muffin 3
1 sl. whole wheat bread 2
1 sl. white bread 1
1 sl. pumpernickel bread 1
1 sl. rye bread 1
1 sl. raisin bread 1
4 saltines 0
|
1/2 cp kidney beans 9
1/2 cp baked beans 7
1/2 cp navy beans 5
1/2 cp pinto beans 5
1/2 cp lentils 2
|
| CEREALS & PASTA |
VEGETABLES |
FRUITS AND NUTS |
1 oz Kellogg's All-Bran Extra Fiber 14
1 oz GM* Fiber One 12
1 oz Kellogg's All-Bran 9
1 cp whole wheat pasta 5
1 oz Kellogg's Bran Flakes 4
1 oz Post Fruit and Fiber 4
1.4 oz Kellogg's Raisin Bran 4
1 oz Nabisco Shredded Wheat'n Bran 4
1 oz oat bran 4
1 oz GM* Raisin Nut Bran 3
1 oz GM* Cheerios 2
1 oz Post Grape-Nuts 2
1 oz oatmeal 2
1 cp popcorn 2
1 oz General Mills Total 2
1 oz General Mills Wheaties 2
1 cp pasta 1
1 oz Kellogg's Corn Flakes 1
1/2 cp cooked brown rice 1
1/2 cp cooked white rice 1
1/2 cp egg noodles 0
*General Mills |
1/2 cp cooked frozen peas 4
1 med baked potato (w/skin) 4
1/2 cp cooked broccoli tops 3
1/2 cp cooked young carrots 3
1/2 cp cooked corn 3
1/2 med fresh avocado 2
1/2 cp cooked green beans 2
1/2 cp Brussels sprouts 2
1/2 cp cooked eggplant 2
1/2 med cooked sweet potato 2
1/2 cp raw cabbage 2
1/2 cp raw bean sprouts 1
1/2 cp raw lettuce 1
1/2 cp sliced raw mushrooms 1
1 med dill pickle 1
1/2 cp mashed potatoes 1
10 med French fried potatoes 1
1/2 fresh tomato 1
1 stalk raw celery 1
6 sl. raw cucumber 1
2 rings green pepper 1
1/2 cp raw onions 1
|
3.5 oz dried figs 18
3.5 oz prunes 8
3.5 oz raspberries 7
1/4 cp almonds 5
1 med apple (w/ skin) 3
1 med banana 3
1/2 cp blackberries 3
5 dried dates 3
1 med nectarine 3
1 med peach (w/ skin) 3
1/4 cp roasted peanuts 3
1 cp strawberries 3
1 pear (with skin) 2
1/4 cp cantaloupe 2
10 med olives 2
1 med orange 2
2 T. peanut butter 2
1 med tangerine 2
1/4 cp walnut pieces 2
1 med apricot 1
10 lg cherries t
1/2 med grapefruit 1
1/2 cp pineapple 1
2 T. raisins 1
2 med plums 1
1/2 cp orange juice 0
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