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Dietary fiber |
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| Dietary fiber is the component in food not broken down by native enzymes and secretions of the gastrointestinal tract but which may be metabolized by the bacteria in the lower gut. Dietary fibers are long-chain carbohydrates (polysaccharides) that are indigestible by the human digestive tract. Dietary fiber comes from the thick cell wall of plants. It is an indigestible complex carbohydrate. Dietary fiber consists of both soluble and insoluble fiber. Soluble fiber dissolves in water while insoluble fiber does not dissolve in water. Both types are important to health in different ways. Soluble fiber includes gums, mucilages, pectin and some hemicelluloses. Cellulose, lignin, and the rest of the hemicelluloses, are all insoluble fibers. |
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Health benefits of high fiber diet |
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| Dietary fiber is widely recognized an important part of the treatment and prevention of diabetes, colorectal cancer, gastrointestinal disorders, high cholesterol, heart disease and obesity. The main value of dietary fiber is that it provides bulk to the bolus moving
through the digestive tract. There are two great advantages to this: by bulking up the bolus, eventually increasing the weight of the stool, it's easier for the digestive system to move it through, and the bulkier stool also tends to retain normal amounts of moisture to make it easier to eliminate with less straining and abrasion.
Soluble fiber has been shown to be able to bind bile salts which may reduce blood cholesterol levels. Low blood cholesterol levels have been associated with a reduced risk of coronary heart disease. Soluble fiber attracts water and forms a gel in the digestive tract. This slows digestion and lowers the rate of nutrient absorption from the stomach and intestine. Soluble fibers can also lower blood sugar levels in people with diabetes. Intake of soluble fiber may also improve glucose tolerance in people with diabetes. Fibers that lower blood cholesterol levels include foods such as apples, barley, beans and other legumes, fruits and vegetables, oatmeal, oat bran and rice hulls. Insoluble fiber acts as a natural laxative that speeds the passage of foods through the stomach. It also gives stool its bulk and helps it move quickly through the gastrointestinal tract. For this reason, insoluble fiber is partially effective as a treatment for constipation. Because the bowel regulation is mostly due to bulking and not to increased water in the stool, it is very unlikely to cause diarrhea unless if taken in massive amounts.
Fiber may protect against the development of colon cancer, for populations consuming high fiber diets have a low incidence of this disease. Fiber could also bind bile acids and other agents that may have a role in producing cancer. Dietary fiber provides a feeling of fullness and adds bulk in the diet. Fiber fills the stomach, reducing appetite. In theory, fiber should therefore reduce eating, leading to weight loss. This also assists digestion and elimination. A high-fiber diet may help prevent type 2 diabetes, lower insulin and blood sugar levels, and improve cholesterol and triglyceride levels in people with diabetes. Fiber intake has also been linked with the metabolic syndrome, a constellation of factors that increases the chances of developing heart disease and diabetes. Fiber also appears to interact with intestinal bacteria and bile acids to process certain food substances. Dietary fiber also has been effectively used for the treatment of diverticulosis. Diverticula are outpouchings that develop on weak areas in the bowel wall.
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Sources of dietary fiber |
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Soluble fiber is found in some fruits (particularly oranges, also apples and bananas), oats, legumes, (peas, soybeans, and other beans), other vegetables, such as broccoli and carrots, and psyllium seed. Legumes also typically contain shorter-chain carbohydrates that are indigestible by the human digestive tract but which are digested by bacteria in the small intestine, which is a cause of flatulence. Whole grains, wheat and corn fiber, and many vegetables like cauliflower, green beans, and potatoes are good sources of insoluble fiber. The skins of fruits and vegetables are also good sources of insoluble fiber. Because of high water content, fruits and vegetables provide less dietary fiber than the drier grains and cereals. Fruits are generally high in pectins while vegetables contain a high percentage of cellulose. Grains, especially wheat bran, are high in hemicellulose.
Over-the-counter, natural fiber supplements can be used, when inadequate fiber is taken in from the diet. There are many types of soluble fiber supplements: psyllium, methylcellulose, pectins, vegetable gums and polycarbophil. Psyllium is digested and does contain calories, may reduce LDL, absorbs water, and may cause gas. Methylcellulose is created from the cell wall of plants. Methylcellulose is undigestible, unfermentable and doesn't cause gas or have calories that humans can use. Both of these can be used for IBS, constipation, diverticulitis. Polycarbophil is also plant based and is similar to methylcellulose. It usually causes even less bloating. |
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Dosage, intake, recommended daily allowance (RDA) |
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The American Dietetic Association (ADA) recommends 20-35g/day for a healthy adult depending on calorie intake (eg. 2000 calorie a day diet should include 25g of fiber/day). For children over age 2, the recommended intake is the child's age + 5 grams. Both types of fiber are crucial for regular large bowel function as it increases stool weight, and improves transit time, as well as decreases absorption of other carbohydrates and fats. |
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Side effects, overdosage symptoms, interactions |
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| A large increase in fiber over a short period of time may result in bloating, diarrhea, gas and general discomfort. An overdose of soluble fiber can cause diarrhea and worsen irritable bowel syndrome. Negative effects of dietary fiber include a reduced absorption of vitamins, minerals, proteins, and calories from the gut. Some insoluble fibers can bind to certain minerals: calcium, magnesium, phosphorus, and iron. Bran, an insoluble fiber, reduces the absorption of calcium enough to cause urinary calcium to fall. Taking fiber supplements without adequate liquids may cause it to swell and, in extreme cases, cause choking. People with esophageal stricture (narrowing of the esophagus) or any other narrowing or obstruction of the gastrointestinal tract should not take fiber supplements. |
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Organic Daily Fiber is a USDA certified organic fiber supplement that naturally supports cleansing for a healthy digestive environment. It is formulated with 100% certified organically grown flax seed and pea hull fiber, alfalfa and barley grasses plus chia seed. Organic Daily Fiber is an excellent source of dietary fiber, providing 5 grams and 20% of the Daily Value in a balanced ratio of soluble to insoluble fiber. It helps entrap toxins such as metals, lead, mercury and other environmental pollutants within the gastrointestinal tract for removal from the body. Organic Daily Fiber provides a unique combination of organic fibers that resists breakdown and fermentation by intestinal flora and will not re circulate toxins into the body. Click here for more information.