Dietary fiber is the undigested plant residue that passes through the intestinal tract. Just as there are many types of plants, there are also types of fiber. Fiber may be soluble (oat bran, psyllium) and form a gelatinous bulk which has cholesterol-lowering properties. Or it may be insoluble (wheat and other grains) which adds 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 complete digestion by removing excess water from food wastes passing into it from the small intestine too quickly, not enough water is absorbed and diarrhea results. In contrast, if waste material is passed to slowly, too much water is absorbed. This results in hard stool 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 many times it weight in water, resulting in softer and bulkier stools. Studies have shown that rural Africans, whose diets are rich in fiber, eliminate food waste in one-third the time it takes urban, Westernized people to do so, and have larger and softer stools. Because of this greater bulk and faster transit time (the time required to digest food and expel wastes), it is believed that harmful substances are also swept out before they can cause problems. 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 easily and quickly. Because of this elimination-easing action, some digestive tract disorders may be avoided, halted or even reversed. 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 10 to 15 grams of fiber a day, whereas 20 to 35 grams are recommended. High fiber foods, such as fruits and vegetables, also tend to be low in calories, so weight gain should not be a problem. Fiber pills generally should not be taken as they contain relatively little fiber and are expensive compared to fiber-containing foods and powder supplements.

A Dietary Fiber Supplement May Be Helpful

Some people don’t tolerate excessive fibrous foods well. Stool softening and bulking agents are available. These products are plant fiber that absorb water and produce 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 substitutes. Most pharmacies carry a generic brand at significant cost savings. Citrucel (hemicelulose) and Equilactin (polycarboxisal) are other bulking agents that can be used. These fiber supplements, in conjunction with foods, are a readily available 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 e chosen every day. Foods that are good sources of fiber are typically low in fat and calories.

SERVING SIZE	BREADS	GRAMS OF DIETARY FIBER
1 medium	bran muffin	3
1 slice	whole wheat bread	2
1 slice	white bread	1
1 slice	pumpernickel bread	1
1 slice	rye bread	1
1 slice	raisin bread	< 1
4 squares	saltines	0
SERVING SIZE	CEREALS AND PASTA	GRAMS OF DIETARY FIBER
1 ounce	Kellogg's All-Bran Extra Fiber	14
1 ounce	General Mills Fiber One	12
1 ounce	Kellogg's All-Bran	9
1 cup	whole wheat pasta	5
1 ounce	Kellogg's Bran Flakes	4
1 ounce	Post Fruit  and Fiber	4
1.4 ounces	Kellogg's Raisin Bran	4
1 ounce	Nabisco Shredded Wheat'n Bran	4
1 ounce	oatbran	4
1 ounce	General Mills Raisin Nut Bran	3
1 ounce	General Mills Cheerios	2
1 ounce	Post Grape-Nuts	2
1 ounce	oatmeal	2
1 cup	popcorn	2
1 ounce	General Mills Total	2
1 ounce	General Mills Wheaties	2
1 cup	pasta	<1
1 ounce	Kellogg's Corn Flakes	<1
1/2 cup	cooked brown rice	<1
1/2 cup	cooked white rice	<1
1/2 cup	egg noodles	0

SERVING SIZE	LEGUMES	GRAMS OF DIETARY FIBER
1/2 cup	kidney beans	9
1/2 cup	baked beans	7
1/2 cup	navy beans	5
1/2 cup	pinto beans	5
1/2 cup	lentils	2
SERVING SIZE	VEGETABLES	GRAMS OF DIETARY FIBER
1/2 cup	cooked frozen peas	4
1 medium	baked potato (with skin)	4
1/2 cup	cooked broccoli tops	3
1/2 cup	cooked young carrots	3
1/2 cup	cooked corn	3
1/2 medium	fresh avocado	2
1/2 cup	cooked green beans	2
1/2 cup	brussels sprouts	2
1/2 cup	cooked eggplant	2
1/2 medium	cooked sweet potato	2
1/2 cup	raw cabbage	2
1/2 cup	raw bean sprouts	1
1/2 cup	raw lettuce	1
1/2 cup	sliced raw mushrooms	1
1  medium	dill pickle	1
1/2 cup	mashed potatoes	1
10 medium	french fried potatoes	1
half	fresh tomato	1
1 stalk	raw celery	<1
6 slices	raw cucumber	<1
2 rings	green pepper	<1
1/2 cup	raw onions	<1

SERVING SIZE	FRUITS AND NUTS	GRAMS OF DIETARY FIBER
3.5 ounces	dried figs	18
3.5 ounces	prunces	8
3.5 ounces	raspberries	7
1/4 cup	almonds	5
1 medium	apple (with skin)	3
1 medium	banana	3
1/2 cup	blackberries	3
5	dried dates	3
1 medium	nectarine	3
1 medium	peach (with skin)	3
1/4 cup	roasted peanuts	3
1 cup	strawberries	3
1	pear (with skin)	2
1/4 cup	cantaloupe	2
10 medium	olives	2
1 medium	orange	2
2 tablespoons	smooth peanut butter	2
1 medium	tangerine	2
1/4 cup	walnut pieces	2
1 medium	apricot	1
10 large	cherries	1
1/2 medium	grapefruit	1
1/2 cup	pineapple	1
2 tablespoons	raisins	1
2 medium	plums	<1
1/2 cup	orange juice	0

This material does not cover all information and is not intended as a substitute for
professional medical care.