dietary fibre

what are examples of soluble fibres

• pectin, guar gum

what are food sources of soluble fibre

• oat bran

• citrus

• inside v + f

• barley

• insides of legumes

what are examples insoluble fibres

• cellulose, lignim

what are food sources of insoluble fibre

• skins of all v + f

• bran of whole grains

• skin of legumes

important to prevent constipation

what does soluble fibre do in the colon

• loose, mesh-work, gel form

• lots of fermentation → gas

• minimal bowel movement bc of fermentation

what are the three gases created by fermentation of soluble fibre in colon?

• 2:0 (acetate) absorbed → bloodstream, used as energy source

• 3:0 (propinate) absorbed → liver, shuts down cholesterol synthesis

• 4:0 (butyrate) preferred energy source by colon cells

what happens to insoluble fibre in the colon

• bacteria has trouble breaking gown

• minimal fermentation

• high bowel movement

what is the structure of the wheat bran

(in to out)

• germ (PUFA + vit. E)

• endosperm (carb + pro)

• aleurone layer (rich in B vit, Fe)

• bran (insol. fibre)

what are the characteristics of soluble fibre and colorectal cancer

• short f.a chain (2:0, 3:0, 4:0)

• low pH in colon (favourable for colon cancer prevention)

• stimulate microbial growth

• low ammonia levels

what are the characteristics of insoluble fibre and colorectal cancer

• bc of building effect, dilution of colon contents

• provides surface for adsorption (byproducts stick to insol. fibre)

• low transit time

• alters bile acid metabolism

  • stops cancer promoter

how does soluble fibre effect blood cholesterol

• usually lowers blood TC + LDL

how does soluble fibre lower blood cholesterol

1. prior learning

2. sol. fibre ferments to 3:0 (propionic acid)

   • absorbed from colon, travels via bloodstream via liver: shuts down cholesterol synthesis

what are the key roles of fibre in weight loss and weight management

1. increase satiety

2. delays gastric emptying (→ stomach → small intestine)

3. takes longer to eat (15-20 min)

   • between time are full to time we sense we are full

what is the current intake of dietary fibre

• 12-15g/day

what are the nutrition recc for canadians (1990)

• no specific #s provided

• “majority of carb choices should be complex carb with an emphasis on whole grains, veg, fruit (+ nut, dees, legumes)”

what is the DRI report for macronutrients and fibre?

• AI: 14g/1000 kcal