Carbohydrate Digestion

Question 1

3 Functions of carbs?

Answer 1

1) supplies energy (from glucose)
2) Protein sparing
3) prevents ketosis

Question 2

Main energy source and how is this stored?

Answer 2

Glucose, stored as glycogen in the liver and muscle

Question 3

How much energy of the NZ diet do carbohydrates produce

Answer 3

40-60%

Question 4

the link between carbs and many ethnicities?

Answer 4

carbs form a staple food for majority of ethnicities around the world.
asian = rice

european = wheat/potatoes

Question 5

Complex carbs and simple sugars eventually end up as

Answer 5

Glucose

Question 6

Types of complex carbohydrates

Answer 6

1) starches: potatoes, bread, rice (glucose)

2) Dietary Fibres:
- INSOLUBLE (bran)
- SOUBLE (lentils, beans)

Question 7

Types of simple carbohydrates?

Answer 7

Sugars: (glucose)

1) Dissacharides - sucrose, maltose, lactose
2) monosaccharides - fructose, glucose, galactose

Question 8

compounds that make up carbs

Answer 8

aldehydes + ketones

Question 9

Types of monosaccharides

Answer 9

glucose, fructose, galactose

Question 10

Galactose

Answer 10

found in milk / dairy products

Question 11

Fructose

Answer 11

found in veges + fruit

Question 12

Types of disaccharides and what makes the

Answer 12

Maltose= glucose + glucose
Sucrose= glucose + fructose
Lactose = glucose + galactose

Question 13

maltose is for

Answer 13

fermentation and alcohol production

Question 14

Sucrose is found in

Answer 14

table sugar + processed foods

Question 15

What are polysaccharides. What is their purpose?

Answer 15

A chain of two or more monosaccharides. Chain may be branched (amylose) or branched (amylopectin + glycogen)

They function as food storage as glycogen

Question 16

Amylose and amylopectin are…?

Answer 16

Both storage polysaccharides of plants. Made up of glucose polymers, they are starches (not water soluble)

-found in cereals, grains, root veges, legumes

Question 17

Features of glycogen (liver & skeletal muscle)

Answer 17

• storage form of glucose
• 12-14 hrs worth stores
• Provides a rapid release of energy when needed
• liver releases first (bloodglucose control)

Question 18

Non-starch polysaccharides are, and what are the types?

Answer 18

polysaccharies with glucose links that can’t be broken (so can’t be digested) = “NSP dietary fibre”
-give very little E

1) SOLUBLE FIBRE: dissolves in water, forms gels, easily digested by bacteria (fermented)
2) INSOLUBLE FIBRE: doesn’t dissolve or form gels, not easily fermented

Question 19

Digestion of Carbs in the mouth?

Answer 19

S: salivary glands secrete saliva into the mouth. Moistens food, amylase hydrolyses starch > small PS

DF: mechanical action of the mouth crushes/mixes DF with saliva for swallowing

Question 20

Digestion of carbs in the stomach?

Answer 20

S: stomach acid inactivates salivary enzymes

DF: DF not digested, delays gastric emptying

Question 21

Digestion of starch carbs in SI?

Answer 21

S: chyme stimulates pancreas to release amylase. This breaks starch down > small PS
PS go to surface of micro villi

DS enzymes on surface of SI cells hydrolyse DS into MS that can now be absorbed

(*DS enzymes specific to specific DS)

Question 22

Digestion of Dietary Fibre in SI and LI

Answer 22

SI: DF is not digested, delays absorption

LI: bacterial enzymes digest DF into SCFA, gas

Question 23

The steps of monosaccharide absorption?

Answer 23

takes place mainly in the SI

1) MS enter capillaries of the intestinal villi
- Glucose & galactose via AT of GLUT-1 transport protein
- Fructose via facilitated diffusion
2) MS travel to liver via Hepatic portal vein
3) in the liver, galactose & fructose > glucose
4) Glucose now available to be used to either control blood sugar or be stored as glycogen

Question 24

Why are people concerned for those who consume excessive amounts of fructose

Answer 24

That they may have issues with excess storage of fructose within the liver > fatty liver

Question 25

What happens when storage of carbs runs out?

Answer 25

body protein > glucose

fat stores > ketones (ketosis)

Question 26

Recommended servings of carbs a day

Answer 26

Preschoolers = 4
children = 5
adults = 6

Question 27

Difference between intrinsic and free sugars?

Answer 27

Intrinsic found in fruit & vege (lactose, fructose)
Free sugar  (sucrose) added by manufacturers, we need to reduce, 50% of NZ intake

Question 28

Insoluble fibre?

Answer 28

provides mass to faeces. Fibres attract water ensure the stools are large and soft

Question 29

Soluble fibre

Answer 29

• Binds w FAs
• prolong emptying (fuller for longer)
• lowers cholesterol + LDL cholesterol
• fermented by bacteria > SCFAs that feed gut enterocytes, ensure appropriate DNA methylation.
• regulates Blood sugar

Question 30

What does your microbiota do?
How do we get it?
What happens if this changes?

Answer 30

Live synergistically, thrive off carbs/fibre (only thing they can proliferate off)

Unique to us, born with, also vaginal delivery and breast millk affects

Changes with: bad diet, illness, AB

Question 31

Recommended intakes of carbs

Answer 31

45-65% carbs
of this 10% simple sugars

15% > 5%

Question 32

What happens when you have a high glycaemic Diet?

Answer 32

1) eat food with HGI, is absorbed very quickly, we get a high peak of blood glucose and insulin (to decrease this)
2) then as your blood glucose & insulin rapidly drops > hyperglycaemic effect > hunger
3) snack again… cycle repeats

Question 33

Why are people encouraged to eat things with a LGI?

Answer 33

creates a more plateau effect (not peaks), fully for longer

Question 34

Symptoms of lactose malabsorption?

Answer 34

bloating, abdominal discomfort, diarrhoea

as sugar overload disrupts the osmotic balance of LI

Question 35

Primary Lactase deficiency? Management?

Answer 35

Genetically predisposed

Managed by: removing milk products from diet
OR taking lactase enzyme tablets with your milk product

Question 36

secondary lactase deficiency?

Answer 36

Due to a condition (gastroenteritis, celiac that destrys villi in SI)&raquo_space; lactose malabsorption

Managed by: initially removing milk products, slowly introducing them back