Lecture 5-dietary fibre

Question 1

• what is glycan?

Answer 1

is the generic name for polysacchrides

Question 2

• define homoglycan and heteroglycan and give an example

Answer 2

homoglycan= only is made of one type of monosachride like celluose

heteroglycan is made up from more than 1 type of monosachride like pectins

Question 3

• describe the branching patterns of polysacchrides

Answer 3

can be linear where there is one 1 reducing and one non-reducing on the polysachirde and then there is a branched form where there is only 1 reducing end and many non-reducing ends

Question 4

• Classification of polysachrides can occur by shape, monomeric-units or by charge give examples from all these categories

Answer 4

1. by shape→ linear example would be cellulose and a pectin would be an example with short branches on linear chains
   
   2. by monomeric units→ homoglycans like cellulose or beta-glucans
   3. by charge→ could be nuetral like cellulose or beta-glucagan or acidic so anionic like pectins

Question 5

• what is the defintion of dietary fiber?

Answer 5

they are carbohydrates that have a degree of polymerization of 3 or more that natrually exsist in foods coming from plants that are resistant to digestion and absorbtion in the small intestine and therefore will be partially or completeyly fermented in the large intestine

Question 6

• what are the two categories dietary fiber is classified into and give examples

Answer 6

1. water-soluble/well fermented fibers= pectin, gums, inulin (oligosacchrides),beta-glucagans, mucilages
   
   2. water insoluble/less fermented fibers= cellulose, hemicellulose, liginin

Question 7

• what are the further division of classifying dietary fiber by solubility?

Answer 7

1. soluble (fermentable)
   1. viscous
   2. non-viscous
   
   2. insoluble (non-fermentable)
      
      1. non-viscous

Question 8

• based on the divisions of fiber by solubility what is its effect on digestion

Answer 8

soluble fiber will create a gel like substance since it gets water within which will slow down the digestive process delaying and decreasing absorbtion of fats and sugars into the blood

insoluble fiber will form a bulk as it does not attract water and will make the digestive process happen faster by enanching movement of stolls to ensure smooth passage out

Question 9

• what does health canada consider as the energy value for carbs that are not digested in the small intestine but fully fermantable in the large intestine and why is that, since it is expected to be 0 in theory

Answer 9

2 kcal because fermantation causes release of fatty acids attributing to this energy value

Question 10

• what is polydextrose?

Answer 10

a non-natural complex of carbs made from glucose that is not digested in the body and that is used as a food additive to increase dietary fiber and is used as a prebiotic

Question 11

• what are the 4 recognized physiological effects of dietary fiber?

Answer 11

1. increases stool bulk so therefore improves laxtation/regularity of laxation (insoluble)
   
   2. reduces blood cholesterol levels (soluble)
   3. reduces post-prandial blood glucose/insulin levels and/or decreases inslulin resisyance (soluble)
   4. from colonic fermantation provides energy-yielding metabolites for the body to use

Question 12

• what are the major sources of dietary fibre in canada?

Answer 12

white flour, potatoes is the main source but then also from veggies and fruit

Question 13

• how much does the average candain eat of fiber and what is the goal?

Answer 13

rn 14-15 g/day the goal should be 25 g/d

Question 14

• how much fiber needs to be contained in a product to be known as a source of fiber

Answer 14

2 grams or more of the refernce amount

Question 15

• what does the gut microbiota do?

Answer 15

hydrolysis of the dietary fiber and ultimately fermentation which leads to production of short fatty acid chains

Question 16

• outline the steps of dietary fiber in the digestive system

Answer 16

1. in the stomach dietary fiber will increase viscocity, slow the breakdown of paricles and therefore slow gastric emptying
   
   2. in the small intestine it will not be digested which will add bulk and viscocity
   3. in the large inestine microbial enzymes will hydrolyze it releasing metabolites and adding bulk to stool retaining water preventing constapation

Question 17

• what is the major end product of colonic fermentation by microorganisms in the colon?

Answer 17

short chain fatty acids

Question 18

• define dybisosis

Answer 18

an imbalnce between the types of organisms present in a persons natrual microflora which basically means their is a lack of needed enzymes to use the carbs from the diet which can lead to gas or explosive diarrhea

Question 19

• describe the difference between probiotics and prebiotics

Answer 19

probitoics are the actual benefical microogranisms themeselves that produce short fatty acid chains like lactobacilli

prebiotics are dietary fiber substances that selectively stimulate the growth/activity of probiotics

Question 20

• what are three examples of prebiotics?

Answer 20

• fructooligosaccharides
  
  • inulin
  • lactulose

Question 21

how can we increase dietary fibers?

Answer 21

• add bran, powdereed or microcrystalinine cellulose
• add fruits and veggies
• add gums as a bulking agent
• replace starch thickeners with gyms
• replace geltain as a gelling agent with gums

Question 22

• describe a low FODMAPS diet

Answer 22

this diet is used to help people who are having digestetive condtions it stands for fermentable oligo,di,monosacchrides and pololys which can cause some digestive distress. The point of this diet is restrict foods high in FOODMAPS for 6-8 then to reintroduce them one at a time every week and if symptoms dont come back you know and can retain a diet that suits u

Question 23

give examples of foods high in FODMAPs

Answer 23

• wheat, barley, rye or anything that has that
• cauliflower, brocoli, cabbage
• dairy foods (exception of old cheese