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.)
Fibre, dietary |
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