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Cancer Treatment Centers of America

All about fiber

In order to get fiber into your diet, you have to eat plants. The fiber in plants is not digested by humans, but contributes to our overall health. It's that plain and simple. What might not be so straightforward is why fiber is so important to your general health and how it can reduce your risk of cancer.

How fiber affects your health

Consuming the National Cancer Institute's recommended 35 grams of fiber per day will help you to:

  • Decrease any inflammatory bowel disease flare-ups.
  • Normalize your serum cholesterol levels.
  • Stabilize your blood sugar levels.
  • Promote weight loss by creating a feeling of fullness.
  • Speed up elimination and regulate your bowel habits.
  • Decrease your risk of breast, colon, esophagus, mouth, ovarian, pharnyx, rectum, stomach and prostate cancers.
  • Reduce and/or absorb cancer causing toxins.
  • Prevent the binding of estrogen to estrogen-dependent tumors.

Not all fibers are created equal

The foods that contain the most fiber are whole grains, legumes, vegetables and fruits. But all fiber is not created equal. Some of these foods contain soluble fiber and others contain insoluble fiber. Most foods contain mixtures of both types of fiber.

Soluble fibers dissolve in water and are classified as pectins, gums and mucilages. This type of fiber is found in apples, carrots, oats, barley and legumes (lentils, beans and peas). Insoluble fibers do not dissolve in water and are classified as lignins, celluloses and hemicelluloses. This type of fiber is found in stringy and cruciferous vegetables, potatoes, fruits with connective tissues or seeds, wheat bran, brown rice and flax seeds.

These two types of fiber have different health benefits. For example, foods containing soluble fiber are used to promote weight loss, reduce cholesterol levels, stabilize blood sugar and speed up bile acid secretions. This type of fiber also tends to produce more gas and intestinal discomfort when eaten in significant amounts. Foods that contain insoluble fiber speed up bowel elimination processes, improve bowel function and reduce bacterial toxin build-up. This type of fiber also reduces the absorption of certain minerals. Consuming a variety of foods, including those containing soluble and insoluble fiber, will best serve all your health needs.

How to add fiber to your diet

  • Start slowly. Gradually move from low fiber to high fiber food items. If you progress too quickly, your digestive tract will let you know by causing uncomfortable gas, bloating and cramping.
  • Drink fluids. You must drink more fluids with fiber rich foods, otherwise you could end up with terrible constipation. Remember, adequate water is necessary to help bulk up the stool for easy passage through the colon.
  • Go for the grains. Eat brown rice instead of white rice; whole grain flour instead of white. Choose crackers, cereals and breads that contain whole grains like wheat, rye, buckwheat, oats, quinoa, millet or amaranth. Remember that whole grains are more perishable than refined grains because of the oil in the germ. They are best stored in a cool, dry place.
  • Crunch that produce. Choose fruits and vegetables with edible skins and seeds. Raw, whole foods will contain the most fiber, but you still can derive fiber from frozen or canned produce. Juice usually contains very little fiber.
  • Lunch on some legumes. Dried beans and peas may cause some intestinal gas if you aren't used to eating them. Lentils, split peas and lima beans are most easily digested. Work up to navy, pinto, kidney or black beans and peas. Taking digestive enzymes with your meals can help reduce much of the bloating and gas.
  • Remember to replace. Adding high fiber foods to your diet can cause you to gain weight if you use them as an addition, rather than as a substitution, for low fiber foods.

A word about fiber pills and powders

Adding powders or fiber capsules to your regular diet may help you achieve some of the health benefits you are looking for. If you choose to take a supplement, choose capsules as they appear to be better tolerated than tablets. Make sure you look for supplements that contain a high level of water soluble fiber, like psyllium. Watch out for products that use sugar, artificial sweeteners or other additives. Above all, make sure you take plenty of water with your supplement!

Fiber supplements, like the fiber found in foods, can bind to certain minerals and inhibit the absorption of certain medications. For these reasons, it is best not to take a fiber supplement with any medications or vitamin and mineral supplements.

Fiber content of selected foods

Apple (with skin) 1 medium 3.0
Dried figs 2 3.5
Orange 1 medium 3.1
Pear (with skin) 1 medium 4.3
Prunes 3 1.8
Raisins (seedless) 1/4 cup 1.9
Strawberries 1 cup 3.9
Broccoli 1/2 cup 2.0
Brussels sprouts 1/2 cup 3.4
Baked potato w/skin 1 medium 3.6
Spinach 1/2 cup 2.0
Sweet potato 1/2 medium 1.7
Carrots (raw) 1 medium 2.3
Romaine lettuce 1 cup 1.0
Tomato (raw) 1 medium 1.6
Baked beans 1/2 cup 9.8
Kidney beans 1/2 cup 7.3
Lentils 1/2 cup 3.7
Peanuts 1/4 cup 2.9
Pumpernickel bread 1 slice 1.9
Brown rice (cooked) 1/2 cup 1.7
Whole wheat bread 1 slice 1.9
Spaghetti (cooked) 1/2 cup 1.1
All-Bran 1/3 cup 8.5
Bran Chex 2/3 cup 4.6
Bran flakes 3/4 cup 5.3
Oatmeal (regular) 3/4 cup 1.6
Raisin bran 3/4 cup 4.8

Data from USDA-Human Nutrition Information Service. Agriculture Handbook No. 8 and Bowes & Church's Food Values of Portions Commonly Used 15th Edition.

by Kim Dalzell, PhD, RD, LD

Excerpt from: Challenge Cancer and Win!