Dietary fiber (also know as "roughage" or "bulk") is the part of the food that is indigestible. Found only in plant foods, it moves unaltered through the stomach and small intestine and into the colon. There are two types of dietary fiber: insoluble and soluble. Insoluble fiber doesn't dissolve in water and travels through the small intestines quickly. Wheat bran, whole grain breads and cereals, as well as the skins of many fruits and vegetables, are considered insoluble. Soluble fiber breaks down as it passes through the digestive tract, forming a gel that traps some substances that are beneficial in lowering cholesterol, stabilizing blood sugar and affecting nutrient absorption. Examples of soluble fibers are
oats, beans, barley, and many fruits and vegetables. Fiber has two well-known benefits:
Prevents and relieves
constipation by stimulating movement of your intestinal muscles, increasing stool bulk and making your stools softer and easier to pass.
Controls weight by creating a feeling of fullness without adding too many calories to the diet.
Dietary fiber also can reduce the risk of many other health conditions including the conditions listed below" Gastrointestinal disorders. Avoiding constipation reduces the risk of developing hemorrhoids (swollen anal tissues), diverticulosis (pouches that protrude through weak spots in the colon) and irritable bowel syndrome (muscle spasms in the stomach walls). Elevated cholesterol. Soluble fiber binds with certain digestive acids made from cholesterol in the liver, and then takes the acids away in the stool. In response, your liver draws cholesterol from your blood to make more acids, thus lowering your blood cholesterol. Diabetes. Soluble fiber slows absorption of blood sugar from the small intestine, making sugar levels easier to control. Heart Disease. Soluble fiber lowers levels of cholesterol, which plays a role in heart disease. Colon Cancer. Insoluble fiber minimizes exposure to carcinogens that may be in the stool by diluting them and speeding their transit through the bowel. Additionally, the insoluble fiber reduces bile acids and certain bacterial enzymes that may promote the growth of precancerous polyps (tissue growths that protrude from a membrane such as the intestinal lining) and colon cancer.
Breast Cancer.Prolonged exposure to increased estrogen and progesterone in the body increases cancer risk. Fiber helps speed cancerous substances, that have reached the intestines, out of the body before they can cause serious damage. Women who eat extra fiber rid themselves of their excess estrogen in bowel movements rather than in urine. This is important because estrogen in the urine can be reabsorbed into the blood stream and eventually reach the breasts and other organs vulnerable to hormone-related cancer. Dietary fiber "binds up" estrogen as it enters the small intestine, and may do the same with other cancer-causing agents, preventing them from being absorbed. Overall, studies have clearly strengthened the belief that fiber not only fights relatively minor intestinal disorders, such as diverticulosis and constipation, but may also help prevent coronary disease and cancer. However, the strongest evidence of a major reduction in risk comes from studies of diets that are rich in high-fiber foods, not just in fiber alone. Such foods, which are low in fat and rich in nutrients, have many health benefits beyond those provided by the fiber itself.
Recommended Daily Allowance Of FiberThe Dietary Guidelines for Americans recommends eating foods that have adequate amounts of fiber. The National Cancer Institute and The American Heart Association (AHA) both recommend consuming
20 to 35 grams of fiber per day. Americans typically consume 10 to 15 grams of fiber per day.
Consuming the following recommended servings of a variety of fruits, vegetables, and grains throughout the day should bring the intake within the range recommended by the National Cancer Institute, AHA, and U.S. Department of agriculture.
Food
Fruits (2 to 4 servings per day)Examples of Serving Size Apple -- 1 medium Banana -- 1 medium Orange -- 1 medium
Vegetables (3 to 5 servings per day) ½ cup cooked or 1 cup rawPeas Potatoes (with skin) Corn Green beans Broccoli Carrots
Grains (6 to 11 servings) Legumes-1/2 cup cookedOatmeal (cooked) -- 1/2 cup Brown rice -- 1/3 cup Whole Wheat bread -- 1 slice 100% Bran -- 1/2 cup
Note: fiber needs fluid to be effective so it's important to drink about 64 ounces of water daily.
Side Effects of FiberIt's important to adjust fiber intake gradually over a period of one to two weeks. This will give the stomach and intestines time to adjust to the dietary change. It will also minimize problems such as diarrhea, bloating or gas that can result when too much fiber is consumed. Moderation is particularly important for older people because their bowel function may be sluggish. It has been feared that very high-fiber diets could, because of fiber's binding abilities, lead to deficiencies of calcium, zinc and other minerals. However, current evidence suggests that moderate fiber intake will not cause nutrient deficiencies. Fiber supplements (such as Citrucel, FiberCon, GenFiber, Hydrocil and Metamucil) should be used only with a physician's recommendations. Taken properly, these supplements may help with constipation, cholesterol levels or intolerance to high-fiber foods, but their anti-cancer benefit is questionable. Relying solely on fiber supplements is unwise because they don't contain the many essential nutrients found in high-fiber foods.
