category: nutrition science: nutrients

Dietary fibers, de.: Ballaststoffe, fr.: fibres alimentaire, it.: fibra alimentare, es.: fibra dietética

Dietary fibres are those components of our food that cannot be or are only partly digested by the human alimentary system. Most dietary fibres are complex carbohydrates, so-called polysaccharides. Their molecules are large and the enzymes in our digestive juices are not able to break them up. Dietary fibres pass the small intestines unchanged and are partly broken down into fats, proteins and simple carbohydrates by bacteria in the large intestines. These products of decomposition are not an active part of the metabolism but dietary fibres are no unnecessary burden as was believed in the past but help with the digestion of our food. They swell in the intestines and increase the amount of the food considerably. This stimulates the production of digestive juices. Dietary fibres also bind mucosa-irritating and incompatible matters and remove them from our body. Furthermore they make defecation easier. Dietary fibres therefore play an important physiological role in digestion.

      Dietary fibres are derived exclusively from plant material, where they stabilise and support the plants. The most important and best known dietary fibres are cellulose, hemicellulose, pectin and pentose. Foods that are rich in dietary fibres are wholemeal products, vegetables and fruits.