Lecture 4b- 1 October 2014 Fibre metabolism and regulation Most of this lecture derived from Chapter 4 of Gropper
Lecture 4b- 1 October 2014
Fibre metabolism and regulation
Most of this lecture derived from Chapter 4 of Gropper
Outline of lectures 4a,bSome Properties-dictate physiological and metabolic effects of fibre a) Water Solubility b) Water Holding/Hydration Capacity as
well as viscosity Slowed Gastric emptying
Reduced mixing of gastrointestinal contents with digestive enzymes
Reduced enzyme function Decreased nutrient diffusion rate Altered small intestine transit time
Outline of lectures 4a,b
Some Properties-dictate physiological and metabolic effects of fibre
c) Absorption or Binding Ability Diminished absorption of lipids Increased faecal bile excretion Lowered serum cholesterol Altered mineral balance
Outline of lectures 4a,bSome Properties-dictate physiological and metabolic effects of fibre
d) Degradability or fermentability Fermentable fibres Increased water and sodium absorption
in colon Mucosal cell proliferation Provision of energy Acidification of luminal environment Non-fermentable fibres Detoxification Increased faecal bulk
Outline of lectures 4a,4b
Recommended Intake of Fibre Implications in Disease Prevention and
Management
Fibre-Based Herbal Medicines
More Detailed InformationDietary Fibre
Recommended Intake of Fibre/Implications in Disease Prevention and Management
25- 35 grams per day-DRI-40 tops, 50 obstruction
soluble fibre- hypocholesterolemic-hypoglycemic
insoluble fibre- laxative
Dietary Fibre
How is fibre metabolism regulated in humans?
A few examples
-intake(form and quantity)
-food preparation
-regulation of bacterial enzymes and pathways sincewe cannot use our own enzymes to digest.
Fibre-Based Herbal Medicines
Echinacea
-few controlled studies
-immune response boost-prevention or treatment of cold, flu or other infections
active agents
-hmw polysaccharides among others
-side effects-allergic reactions may occur -use in systemic or immune system dysfunction is contraindicated
Fibre-Based Herbal MedicinesGinseng
-cancer prevention-fatigue reduction
-few controlled studies
-active agents-saponin glycosides and ginsenosides-modulate hormones and central nervous system
function
-side effects-negative interactions with warfarin
Fibre-Based Herbal Medicines
Ginkgo biloba -vascular flow -free radical scavenger
-few controlled studies-
-active agents-flavone glycosides-see above for effects
-side effects-headaches, dizziness, palpitations
Fibre-Based Herbal Medicines
Garlic -lower cholesterol -anti-platelet aggregatory - a number of controlled studies-
-active agents-allicin-see above for functions
-side effects-heartburn, flatulence-anticoagulant function synergy
Fibre-Based Herbal Medicines
St. John's Wort -depression -anxiety
a few well- controlled studies-
-active agents-MAO inhibitor-fights depression
-side effects-fatigue, allergic reactions, photosensitivity
Fibre-Based Herbal Medicines
Golden seal -canker sores
a number of controlled studies-
-active agents-alkaloids-see above for functions
-side effects-none reported
Fibre-Based Herbal Medicines
Summary-figure 5.2 Gropper-no satisfactory definition of fibre
-SCFAs provide energy therefore fibre is energy yielding
-varied soluble and insoluble fibre content in different foods-implications for suchdifferences?