DIETARY FIBRE is the indigestible portion of dietary carbohydrates and related substances which reach the colon. Three types of dietary fibres can be found in foodstuffs:
1. insoluble fibre (cellulose, hemicellulose) that is largely inert metabolically, absorbing water throughout the digestive system and easing defecation
2. soluble fibre (beta-glucans, pectin, gums, inulin) that can be fermented in the colon into gases and physiologically active byproducts
3. resistant starch.
Diets naturally high in fibre bring about several main physiological consequences:
• help promote regularity and prevent diverticular disease
• improve gastrointestinal health
• reduce in the risk of developing some cancers, such as colorectal cancer
• improve glucose tolerance and insulin response
• reduce hyperlipidaemia, hypertension, and other coronary heart disease risk factors
• increase satiety and assist in weight management
Although not yet formally proposed as an essential macronutrient, dietary fibre is regarded as important for the diet, with regulatory authorities in many developed countries recommending increases in fibre intake.