What Is Fiber?

Dear Dr,
There has been a lot of talk of fiber in the media in recent times and I just felt you could help throw more light on it.Thank You
Francis, Abuja

Dear Francis,
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. 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. 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: They enclose and package the nutritious parts of the plant, especially the storage organs that are rich in starch, and the parts of the cells that contain sugars, vitamins, and minerals. They provide a tough protective armor around the embryo of the future plant. The simple reason fibre is indigestible is that human beings do not produce the enzyme cellulase which you need to digest plant (cell wall) matter. The upshot? Take lots of fruits and vegetables for much easier digestion, and to have better bowel movements or better alimntarey function which also means plenty of stools to pass and less constipation.
Cheers