Indigestible plant material in food. Dietary fibre includes certain types of polysaccharides, cellulose, hemicelluloses, gums and pectins (see carbohydrates), and lignin. Humans do not have the necessary enzymes to digest these substances, which pass through the digestive system virtually unchanged and cannot be used as a source of energy.
Some components of dietary fibre hold water, thereby adding bulk to the faeces and aiding bowel function. For this reason, dietary fibre can be effective in treating constipation, diverticular disease, and irritable bowel syndrome. Unrefined carbohydrate foods such as wholemeal bread, cereals, and root vegetables are rich in fibre. (See also nutrition.)
It has been discovered that various cultures round the world, e.g. the Hunza Colony near Pakistan, the 7th-Day Adventists and others who eat high fibre foods have fewer cases of diabetes, heart disease, arthritis and other degenerative diseases. Natives of Hunza may live to great ages and have few dental problems, emotional illness and never require a laxative. Today, foods may be over-processed.
Other diseases recognised to be characteristic of modern western civilisation and claimed to be causally related to diet are: appendicitis, coronary heart disease, hiatus hernia, diverticulosis, piles and other anal disorders, obesity, gall stones, hypertension, deep vein thrombosis and varicose veins.
Low fibre intake results in slow transit of food and exposes potential carcinogens a longer period of time in contact with the alimentary canal. A high fibre diet tends to absorb a variety of environmental pollutants and eliminate them from the body.
Foods rich in fibre: wholemeal bread, grains, cereals, brown rice, beans, peas, boiled cabbage, sweetcorn, banana, prunes (stewed), dried apricots. One of the highest is All Bran, which has the highest proportion of dietary fibre among breakfast cereals with no preserves, artificial colouring or flavouring. Contains one-third fewer calories than most breakfast cereals and because of its glycaemic effect is useful in diabetic diet. ... fibre
The transmission of images through bundles of thin, flexible glass or plastic threads which propagate light by total internal reflection. This means that all the light from a powerful external source travels the length of the fibre without losing its intensity. Fibre-optics have led to the development of endoscopes, which enable structures deep within the body to be viewed directly.... fibre-optics
(roughage) nonstarch polysaccharides (NSP), which cannot be digested and absorbed to produce energy; specifically, sources of NSP that do not contain lignin or resistant starch. Fibre is divided into two types: insoluble (cellulose and hemicelluloses) and soluble (pectins). Highly refined foods, such as sucrose, do not contain dietary fibre. Foods with a high fibre content include wholemeal cereals, vegetables, nuts, and fruit. A diet high in insoluble fibre (e.g. wheat bran, wholegrain and wholemeal bread and cereals) may help prevent bowel diseases, such as constipation, diverticulitis, and colon cancer. Soluble fibre (e.g. oats, barley, beans, pulses, fruit, and vegetables) slows the reabsorption of *bile salts and so helps to lower cholesterol as well as dampening the glycaemic response to glucose (see glycaemic index). A high-fibre diet used to be the first-line advice for irritable bowel syndrome; however, a low *FODMAP diet can be more effective.... dietary fibre
the long fine process that extends from the cell body of a *neuron and carries nerve impulses. Bundles of nerve fibres running together form a *nerve. Each fibre has a sheath, which in medullated nerve fibres is a relatively thick layer containing the fatty insulating material *myelin.... nerve fibre
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