1. The new normal-Globe and Mail- 30 September parents do not recognise when they and/or others including kid(s) is/are overweight or obese
Fat is the new normal

2. Lecture 4a- 23 January 2017
Fibre metabolism and regulation
Most of this lecture derived from Chapter 4 of Gropper

3. Outline of lectures 4a,b
Definition of Dietary Fibre
Plants and Fibre
Dietary Fibre

4. Outline of lectures 4a,b
Some 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

5. 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

6. Outline of lectures 4a,b
Some 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

7. Outline of lectures 4a,b
Recommended Intake of Fibre
            Implications in Disease Prevention and Management
Fibre-Based Herbal Medicines

8. Outline of lectures 4a,b
Summary

9. More detailed information
Definition of Dietary Fibre
        -not a single entity and therefore no universal definition
        -one attempt at definition- "plant polysaccharides and lignin which are resistant to hydrolysis by the digestive enzymes of man"- Trowell et al quoted in Chapter 5, Gropper 3rd edition
        -however, there are problems with this definition

10. Problems with definition-direct quote from Gropper, Chapter 5
“fails to include all the digestible residue
from food that may reach the colon.
It uses the ability to be digested as the basis for the definition when undigested food reaching the colon does not necessarily lack the ability to be digested
nor is it necessarily unavailable to the body”

11. Health Canada Definition of Dietary Fibre (most recent 2012)• .
Health Canada Definition of Dietary Fibre (most recent 2012)
Dietary fibre consists of:
carbohydrates with a DP1 of 3 or more that naturally occur in foods of plant origin and that are not digested and absorbed by the small intestine; and
accepted novel fibres.
Novel fibres are ingredients manufactured to be sources of dietary fibre and consist of carbohydrates with a DP of 3 or more that are not digested and absorbed by the small intestine. They are synthetically produced or are obtained from natural sources which have no history of safe use as dietary fibre or which have been processed so as to modify the properties of the fibre contained therein. Accepted novel fibres have at least one physiological effect demonstrated by generally accepted scientific evidence."
1DP: degree of polymerization or number of saccharide units.

12. Health Canada Definition of Dietary Fibre (most recent 2012)• .
Health Canada Definition of Dietary Fibre (most recent 2012)
The substances in part 1 of this definition are all edible plant materials that have a history of use as food and have been processed or cooked using conventional processes. They include fruits, vegetables, pulses, seeds, nuts, cereals, legumes, etc.
Some minor substances, such as lignin, waxes, cutin, suberin, phytate, and tannin, although not carbohydrates, are an integral part of dietary fibre and are intricately tied to the plant polysaccharides, often serving as chemical cross-links between various components and increasing resistance to digestion in the small intestine. These substances, as well as some proteic fractions, are not separated from the polysaccharides in some gravimetric methods. Therefore, they are included in the definition of dietary fibre when they are part of the plant cell wall matrix, but they cannot be defined as dietary fibre if they are isolated and introduced into a food.
Substances in part 2 of the definition include, for example, substances obtained from agricultural crop by-products and from raw plant materials, substances of animal or bacterial origin, chemically modified substances, synthetic products, etc. These substances are not historically used as food fibre sources. The term "novel fibre" is used only during the pre-market review process involving Health Canada, the food industry, and the Canadian Food Inspection Agency. Once a novel fibre source has been accepted by Health Canada, it is labelled as dietary fibre and is known as such.

13. • .
Health Canada kcal/gm (metabolisable energy) for fibre (most recent 2012)
Health Canada considers the energy value for carbohydrate that is not digested in the small intestine, but is fully fermented in the large intestine, is 2 kcal (8 kJ) /g. This will be the general value used for all unavailable carbohydrate, including dietary fibre, in the absence of specific values. This will also apply to inulin for which the previously calculated value was 2.2 kcal (9.2 kJ) /g.
Products with energy values lower than 2 kcal (8kJ) /g, which have already been accepted by Health Canada based on scientific evidence, may carry a label declaration of these specific caloric values. Thus, the energy value of the fibre portion of wheat bran is 0.6 kcal (2.5 kJ) /g and the wheat bran itself has an energy value of 2.4 kcal (10 kJ) /g. Polydextrose, an eligible fibre source under the new definition, has been previously accepted as having an energy value of 1 kcal (4 kJ) /g given that it is only partially fermentable

14. Plants and Fibre
       -fibre is derived from plant cells
       -plant cell wall contributes more than percent of dietary fibre
        -figure 5.1 –Gropper
        -figure 5.3-Gropper

15. Plants and Fibre
      

16. Plants and Fibre
      

17. Fibre-
water insoluble and water soluble
   

18. Fibre-
water insoluble
     -cellulose-bran, legumes, peas, root vegetables, cabbage family veggies, apples, outer covering of seeds
         -poorly fermented generally
   

19. Fibre-
water insoluble
-hemicellulose-not water soluble if do
NOT have acid side chains
-bran and whole grains(not clear if water
or water insoluble or both)
                                           
-fermentability depends on sugar and acid composition-eg hexose and uronic acid are more accessible to bacterial enzymes
   

20. Fibre-
water insoluble
lignin-a non-carbohydrate component of fibre-
wheat,
fruits with edible seeds (eg strawberries) ,
mature root veggies (eg carrots)
           -poorly fermented
   

21. Fibre-
water soluble
-water soluble-refers to hot water
            

22. Fibre-
water soluble
-water soluble-refers to hot water
                 -hemicellulose-water soluble if have acid side chains
              
            

23. Fibre-
water soluble
-pectin-gel forming
                                  
-apples, strawberries
and citrus fruits
                      -easily fermented
            

24. Fibre-
water soluble
       -gums
                       -oatmeal, barley and legumes
                       -eg: gum arabic
                       -easily fermented
            

25. Fibre-
water soluble
-mucilages
          -similar in structure to gums
          -synthesised by plant secretory cells
          -carrageenan and agar-dervived from seaweed and algae
                -used as stabilisers in ice cream
for example
-degraded by colonic bacteria
            

26. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
            a) Water Solubility
                     -generally water soluble
-delay gastric emptying
                                    -increase transit time
                                    -decrease nutrient (glucose absorption)
            

27. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
            a) Water Solubility
                     generally water insoluble
                                    -decrease transit time
-increase faecal bulk
            

28. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
b) Water Holding/Hydration Capacity as well as viscosity
             -ability of fibre in food to bind water-ie sponge effect
             -water soluble fibres have greater hydration capacity than?
            

29. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
b) Water Holding (whc)/Hydration Capacity
as well as viscosity
             -water holding capacity dependent on water solubility, pH of gastrointestinal tract, size of fibre particles and degree of food processing
-increased pH increases whc
             -coarsely ground bran has higher
hydration capacity
            

30. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
b) Water Holding/Hydration Capacity as well as viscosity
-water holding by fibre creates viscous
solutions resulting in:
                      Slowed gastric emptying-satiety
                      Reduced mixing of gastrointestinal contents with digestive enzymes- physical barrier
                      
            

31. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
b) Water Holding/Hydration Capacity as well as viscosity
-water holding by fibre creates viscous solutions resulting in:
                    Reduced enzyme function
-eg inhibit -intestinal peptidases
                                             -pancreatic lipase
                                             -mechanism is unclear
                      
            

32. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
b) Water Holding/Hydration Capacity as well as viscosity
-water holding by fibre creates viscous solutions resulting in:
              Decreased nutrient diffusion rate and hence nutrient absorption
                       -passage through mucin layer is
reduced
                                             
            

33. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
b) Water Holding/Hydration Capacity as well as viscosity
-water holding by fibre creates viscous solutions resulting in:
              Decreased nutrient diffusion rate and hence nutrient absorption
                       -reduced convective currents
                                             
            

34. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
b) Water Holding/Hydration Capacity as well as viscosity
-water holding by fibre creates viscous solutions resulting in:
        Decreased nutrient diffusion rate and hence nutrient absorption
                 -results in decreased absorption of amino acids and fatty acids due to viscous fibre
                                                              
            

35. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
b) Water Holding/Hydration Capacity as well as viscosity
-water holding by fibre creates viscous solutions resulting in:
                Decreased nutrient diffusion rate and hence nutrient absorption
                         -pectin, psyllium and viscous mucilaginous gums (eg guar gum) lower blood glucose and hence hormonal response to glucose
                      
            

36. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
b) Water Holding/Hydration Capacity as well as viscosity
-water holding by fibre creates viscous solutions resulting in:
            Altered small intestine transit time
                -soluble -increase transit time- good- why?
                -insoluble-decrease transit time- bad-why?
                                        -net effect?
                      
            

37. Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
     c) Absorption or Binding Ability
                -lignins, gums, pectins and some hemicelluloses have ability to bind(adsorb) enzymes, nutrients in gi
tract
                                                           
-dependent on gi pH, particle size,
food processing and fermentability
                                                
            

38. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
     c) Absorption or Binding Ability
               -lignins, gums, pectins and some hemicelluloses have ability to bind(adsorb) enzymes, nutrients in
gi tract
                                                           
-results in-diminished lipid absorption
                                     -lowered blood cholesterol
                                     -increased faecal bile excretion
-changed mineral balance
                                                
            

39. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
     c) Absorption or Binding Ability
               -lignins, gums, pectins and some hemicelluloses have ability to bind(adsorb) enzymes, nutrients in
gi tract
                                                           
Diminished Absorption of Lipids
                              -pectin, guar gum, oatbran, lignin- adsorb fatty acids, cholesterol, bile acids
                               -consequence of such adsorption
                        
                                                
            

40. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
c) Absorption or Binding Ability
                -lignins, gums, pectins and some hemicelluloses have ability to bind(adsorb) enzymes, nutrients in
gi tract
                                                           
Diminished Absorption of Lipids
Increased faecal bile excretion
                      -similar mechanistic consequence
seen under diminished
absorption of lipid
                      
            

41. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
c) Absorption or Binding Ability
                -lignins, gums, pectins and some hemicelluloses have ability to bind(adsorb) enzymes, nutrients in
gi tract
                                                           
Lowered serum cholesterol
                                consequently more plasma cholesterol is used to synthesise bile                               
                      
            

42. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
c) Absorption or Binding Ability
                -lignins, gums, pectins and some hemicelluloses have ability to bind(adsorb) enzymes, nutrients in
gi tract
                                                           
Altered mineral balance
                                -fibre containing uronic acid can
form cationic bridges with minerals
                               
                      
            

43. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
c) Absorption or Binding Ability
                -lignins, gums, pectins and some hemicelluloses have ability to bind(adsorb) enzymes, nutrients in
gi tract
                                                           
Altered mineral balance
                                -lignins also thought to play a role
                                -slower the fermentation the higher the ability to bind minerals by bacteria
                                                               
                      
            

44. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
c) Absorption or Binding Ability
                -lignins, gums, pectins and some hemicelluloses have ability to bind(adsorb) enzymes, nutrients in
gi tract
                                                           
Altered mineral balance
                                -more rapidly fermentable fibres eg pectin may have positive effect on mineral balance
                               
                      
            

45. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
d) Degradability or fermentability
                   -principal metabolites of fibre and undigested starch fermentation are lactate and short chain fatty acids (SCFAs)
                  -also get some hydrogen, CO2 and methane gases
                  -pectin, gums, oat and wheat bran and psyllium produce SCFAs
                               
                      
            

46. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
d) Degradability or fermentability
                 Fermentable fibres
                     Increased water and sodium absorption in colon
              -SCFA rapid absorption stimulates
water and sodium absorption
                                                    
                      
            

47. Dietary Fibre d) Degradability or fermentability Fermentable fibres
Some Properties-dictate physiological and metabolic effects of fibre
d) Degradability or fermentability
                 Fermentable fibres
                     
                     Mucosal cell proliferation
                               -substrates from degradation of
dietary fibre
                     Provision of energy
                               -SCFAs
                     Acidification of luminal environment
                           -SCFAs-calcium more available to bile and fatty acids- may be protective against colon cancer
                               
                      
            

48. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
d) Degradability or fermentability
                 Non-Fermentable fibres
                     
                      -principally cellulose and lignins-promote proliferation of colonic microbes
                       Detoxification
                                via proliferation of colonic microbes
                                                      
                      
            

49. Some Properties-dictate physiological and metabolic effects of fibre
Dietary Fibre
Some Properties-dictate physiological and metabolic effects of fibre
d) Degradability or fermentability
                 Non-Fermentable fibres
                     
                   Increased faecal bulk-good laxative effect
                         bulk consists of undigested fibre, salts and
water
                       -wheat bran and especially rice bran
particularly good at this