DIETARY FIBER

 What is dietary fiber?
Fiber is defined as the part of a plant product that is not digested by the enzymes of the human gastrointestinal tract.

 

What are the benefits of dietary fiber?
-- Helps regulate bowel movements and improve diarrhea and constipation.
-- Decreases risks of diverticulitis (infection in the diverticula) or diverticular bleeds.
-- Assists in the healing of hemorrhoids and anal fissures.
-- Lowers blood cholesterol levels.
-- Reduces the risk of colon cancer.
-- Aids in weight loss by providing bulk to the diet with little added calories.

 

What are the sources of dietary fiber?
Virtually all vegetable materials and fruits contain fiber, while meat, eggs and dairy products are devoid of it. Per serving, apples, raspberries, prunes, raisins and bananas are the richest source of fiber. Among the vegetables, corn, cabbage broccoli and potatoes are the richest in fiber. Most of the beans and lentils are also high in fiber as are cereals, whole grain breads and bran.

 

How does the dietary fiber help in the management of constipation?
The primary role of the product is to trap water and carry it into the stools thus softening the bowel movements. To have ANY effect, fiber MUST be taken with ample water. It would be self-defeating and even harmful to consume fiber, particularly fiber supplements, with only small amounts of water. While fiber is most frequently prescribed to help relieve constipation, it is also very useful in managing patients with chronic, benign, low volume diarrhea. There the fiber will trap the excess water present in the stools giving the stools greater firmness.

 

Any side effects to the ingestion of fiber?
Yes. Patients who have a decreased rate of emptying of the stomach (untreated hypothyroid, chronic diabetics) may retain fiber in their stomach for long periods of time and as such complain of nausea and vomiting even after small meals. Among healthy individuals, fiber can cause a sensation of bloating. If the main source of fiber is vegetable material, one can also expect an increased amount of intestinal gas (associated with almost any vegetable but more so with cabbage, onion, broccoli and cauliflower). Bloating and excess gas are best overcome by gradually increasing the fiber intake and adding fiber supplements. For patients who need fiber supplements I usually recommend starting with 1 teaspoonful of Metamucil in an 8 ounce glass of water daily (3.4 grams of fiber and 30 calories) and gradually increasing to 1 tablespoon in a 16 ounce glass of water twice a day (13.6 grams of fiber and 120 calories).

 

The recommended dose of fiber is 30-40 grams daily. The following is a list of fiber contents per serving of commonly consumed items:

 

ITEM

SERVING SIZE
GRAMS OF FIBER
Breakfast material    

Extra Fiber Bran Cereal

1 oz.
12

All Bran

1 oz.
9

Raisin Bran

1 oz.
4

Oatmeal

1 oz.
3

Shredded Wheat

1 oz
2.5

Cornflakes

1 oz.
0.3

Cream of Wheat

1 oz.
0.3
Fruits    

Prunes

3
5

Banana

1
4

Apple with skin

1
3.4

Raisins

1/4 cup
3.1

Strawberries

1 cup
3

Orange

1
2.6

Grapes

1/2 cup
0.7

Grapefruit

1/2 cup
0.6
Vegetables    

Corn

1/2 cup
4.6

Peas

1/2 cup
3.6

Broccoli

1/2 cup
2.9

Tomato

1 cup
2.5

Carrots

1/2 cup
2.3

Spinach

1/2 cup
2.1

Cucumber with skin

1
1.2

Legumes

   

Baked beans

1/2 cup
8.8

Kidney beans

1/2 cup
7.3

Navy beans

1/2 cup
6.0

Lentils

1/2 cup
3.7
Miscellaneous    

Whole wheat spaghetti

1 cup
3.9

Bran muffin

1
2.5

Popcorn

1 cup
2.5

Spaghetti

1 cup
1.1

Rice, brown

1/2 cup
1.0

Rice, white

1/2 cup
0.2

 

Revised 8/08

 

ŠTed A. Tobey, M.D., Inc. ~ All Rights Reserved