high fibre

Last reviewed 06/2021

Dietary fibre or roughage is the elements of food which cannot be digested. It consists of:

  • celluloses
  • hemicelluloses
  • lignin
  • pectins

Poor dietary fibre consumption has been linked with the onset of a number of disease states in the 'developed' western world:

  • irritable bowel syndrome
  • chronic constipation
  • diverticular disease
  • appendicitis
  • haemorrhoids
  • hiatus hernia
  • gallstones
  • colonic carcinoma
  • atherosclerosis

The amount of fibre in the diet has a direct influence on the quantity and consistency of stool produced, and the stool transit time. In the Western world, an adult produces between 80 g and 120 g of firm stool each day with a stool transit time of about 3 days. This is in contrast with an adult in the third world, who has a diet that is similar to that of the hunter-gatherer, i.e. whole grains, cereals, legumes and nuts, supplemented by small quantities of meat and fish, who produce between 300 g and 800g of stool per day with a stool transit time of about one and a half days.

Dietary fibre also influences bile salt metabolism: an increasing amount of deoxycholate is formed from cholate.