What Is Fiber?
Monday, February 20, 2017 - 06:46David Kritchevsky Ph D
Dr K W Heaton MD FRCP
Guy Slowik FRCS
Fiber is a virtually indigestible substance that is found mainly in the outer layers of plants. Fiber is a special type of carbohydrate that passes through the human digestive system virtually unchanged, without being broken down into nutrients. Carbohydrates constitute the main source of energy for all body functions.
Almost everyone hears about the need for enough fiber in the diet. But few people understand the importance of dietary fiber - or where to get it.
Fiber is important because it has an influence on the digestion process from start to finish:
- Because it demands that food be more thoroughly chewed, fiber slows down the eating process and helps contribute to a feeling of being full, which in turn can help prevent obesity from overeating.
- Fiber makes food more satisfying, probably because the contents of the stomach are bulkier and stay there longer.
- Fiber slows digestion and absorption so that glucose (sugar) in food enters the bloodstream more slowly, which keeps blood sugar on a more even level.
- Fiber is broken down in the
colon (the main part of the large intestine) by bacteria (a process called fermentation), and the simple organic acids produced by this breakdown helps to nourish the lining of the colon. - These acids also provide fuel for the rest of the body, especially the liver, and may have an important role in metabolism.
Substantial amounts of fiber can be found in foods such as:
- All-natural cereals
- Whole-grain breads
- Beans
- Fruits
- Vegetables
- Nuts
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Nice To Know: Only plants produce fiber. No matter how chewy or "tough" animal products may be, they do not contain fiber - not even bones or eggshells. |
There are two main types of fiber, and they have different effects on the body:
Insoluble fiber is mainly made up of plant cell walls, and it cannot be dissolved in water. It has a good laxative action.Soluble fiber is made up of polysaccharides (carbohydrates that contain three or more molecules of simple carbohydrates), and it does dissolve in water. It has a beneficial effect on body chemistry, such as lowering blood cholesterol and blood sugar levels.
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Nice To Know: Dietary fiber is essentially the cell walls of plants. Cell walls provide the architecture or skeleton of a plant and serve several purposes:
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Nice To Know: The understanding that Today, obesity is the most common form of malnutrition and is a factor in the two major causes of death - heart disease and cancers. So any food that helps people limit calories is desirable. It was a naval doctor, T.L. Cleave (1906-83) who sparked the great re-think about fiber. He argued that refined or fiber-depleted carbohydrates are harmful in many ways. He was supported by a surgeon from East Africa, Denis Burkitt, who presented evidence that Western diseases are rare in Africa and other third-world countries where fiber intake is high. |
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Facts about fiber
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