Nutrition and Health

Fibers are water-soluble, except cellulose, hemicellulose, and lignin, all of which form part of cell walls. Soluble fibers are sticky and combine with water to form gel-like substances. Pectin is a water-soluble fiber found in soft fruits and vegetables. Gums that are common food additives are also water-soluble, found in stems and seeds of some tropical plants. In general, fruits are higher in pectin and vegetables are higher in cellulose. Although cellulose and hemicellulose are not hydrolyzed, intestinal bacterial can digest some fiber to produce lipid fragments known as short-chain fatty acids. These fatty acids are absorbed in the colon and yield energy when metabolized.

Fiber's Effect on the Body

Water insoluble fibers pass through the gastrointestinal track unchanged, absorbing up to 15 times their weight. This is important since they provide the digestive tract with `bulk' that facilitates passing food through the intestines to be evacuated as solid waste. As a result, fiber often is called "nature's natural laxative". Cellulose's ability to absorb water produces softer stools and regular bowel movements. Also, insoluble fiber may prevent colon and rectal cancer and help to control diverticulosis (A sac or pouch in the walls of a canal or organ [e.g., GI tract] that becomes inflamed and causes pain and stagnation of feces. Source: The American Dietetic Association's Complete Food & Nutrition Guide, p. 145). Water-soluble fiber, as found in beans, fruit, and oat bran lowers cholesterol by binding to the cholesterol found in liver bile, to help control diabetes.

Overall, dietary fiber does not provide much nutritional value to the human diet because the body is unable to break down these carb sources for energy. Yet, fiber reduces available calories by providing a sense of satiety and by absorbing some nutrients, including fat. Fiber also absorbs and eliminates essential fatty acids, food substances essential for good health and energy metabolism.

Also, dietary fiber may be a detoxifier since it binds with some toxic substances before elimination. A diet extremely high in fiber is not a good idea since it impairs calcium, iron, and zinc absorption in the intestine.

Increasing Your Dietary Fiber

Increasing dietary fiber should be a gradual process. The majority of fiber products may cause unpleasant bloating, cramps, gas, and other symptoms - especially if they are eaten in large amounts at once. It is best to add one high fiber food at a time to judge whether the food causes symptoms or not. For instance, some people who have problems with brown rice may tolerate apples, oatmeal, whole wheat bread, or other sources of similar fiber.

Many nutrition authorities advise consuming 20-35 grams of fiber daily. When choosing fiber-rich foods, note that the nutritional value of wheat products varies. This occurs because refining grains remove part of the seed (e.g., bran, endosperm, and germ). In general, the less refining, the greater the dietary fiber value of any food.

Here are some fiber-rich sources to improve your diet and nutrition:

• 1 ounce dry-roasted peanuts: 2.2 g
• 1/2 cup cooked broccoli: 2.2 g
• 1 potato with skin: 2.5 g
• 1 slice whole wheat bread: 2.8 g
• 1 cup carrots: 3.0 g
• 1/2 large grapefruit: 3.1 g
• 1 apple: 3.5 g
• 1 cup cooked long-grain brown rice: 3.3 g
• 1 cup cooked instant oatmeal: 3.5 g
• 3 cups air-popped popcorn: 3.7 g
• 1 pear: 4.3 g
• 1 cup raisins: 4.5 g
• 1 cup of whole wheat spaghetti cooked: 5 g
• 1 cup baked beans: 7.0 g
• 1 cup of chickpeas: 7 g
• 1 cup boiled lentils: 7.9 g
• 1 serving bran cereal: 11 g

Types of Dietary Fiber

There are many different sources of fiber. Each has a specific use in the body. Use the following listing as a guide to your dietary fiber choices :

• Cellulose: Fruit legumes, nuts, oat bran, seeds, whole grains, and vegetables. Adds bulk to stool to reduce constipation; oat bran lowers cholesterol; may help control blood sugar; helps weight loss by displacing calories.
• Gums: Algae, barley, fruits, legumes, oats, seaweed, seeds, and vegetables. Adds bulk to stool to reduce constipation; may lower blood cholesterol; helps control blood sugar; helps weight loss by displacing calories.
• Hemicellulose: Fruits, legumes, nuts, oat bran, seeds, whole grains, and vegetables. Adds bulk to stool to reduce constipation; oat bran lowers cholesterol; may help control blood sugar; helps weight loss by displacing calories.
• Lignins: Woody parts of bran, fruit skins, nuts, seeds, whole grains and vegetables. Adds bulk to stool to reduce constipation; may lower blood cholesterol; may help control blood sugar; helps weight loss by displacing calories.
• Mucilages: Plant seeds and secretions. Adds bulk to stool to reduce constipation; may lower blood cholesterol; helps control blood sugar; helps weight loss by displacing calories.
• Pectins: Algae, barley, fruits, legumes, oats, seaweed, seeds, and vegetables. Adds bulk to stool to reduce constipation; may lower blood cholesterol; helps control blood sugar; helps weight loss by displacing calories.