Table 1 Dietary fibre- physico-chemical characteristics and relationships to gut effects (modified from [9])

Water-holding capacity & viscosity

Slows gastric emptying;

Changes digesta mixing;

Alteration of digestive enzyme activity;

Stimulates passage rate;

Slows digestion, especially of protein and lipids;

Associated with reduced plasma cholesterol;

Blunting of glycaemic response

[11,12,13]

Bulking

Gastric distension;

Changes in mixing & diffusion;

Decrease food intake;

[14, 15]

Adsorption of compounds (e.g. bile salts, polyphenols & minerals)

Increases bile acid excretion & other compounds;

Retention of polyphenols until large intestine;

Blood cholesterol; fermentation of polyphenols;

[16, 17]

Encapsulation

Plant cell walls encapsulate e.g. starch granules;

Transport of starch (resistant) to LI for fermentation;

[18,19,20,21]

Fermentability

Increases microbial biomass & fermentation end-products (e.g. SCFA);

Induces selection of specific microbes;

Energy for colonocytes; influences satiety; faecal bulking; “colonization resistance” to pathogens;

[22, 23]