Carbohydrate Digestion Flashcards Preview

Digestive System > Carbohydrate Digestion > Flashcards

Flashcards in Carbohydrate Digestion Deck (36):
1

3 Functions of carbs?

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

2

Main energy source and how is this stored?

Glucose, stored as glycogen in the liver and muscle

3

How much energy of the NZ diet do carbohydrates produce

40-60%

4

the link between carbs and many ethnicities?

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

european = wheat/potatoes

5

Complex carbs and simple sugars eventually end up as

Glucose

6

Types of complex carbohydrates

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

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

7

Types of simple carbohydrates?

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

8

compounds that make up carbs

aldehydes + ketones

9

Types of monosaccharides

glucose, fructose, galactose

10

Galactose

found in milk / dairy products

11

Fructose

found in veges + fruit

12

Types of disaccharides and what makes the

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

13

maltose is for

fermentation and alcohol production

14

Sucrose is found in

table sugar + processed foods

15

What are polysaccharides. What is their purpose?

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

They function as food storage as glycogen

16

Amylose and amylopectin are...?

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

-found in cereals, grains, root veges, legumes

17

Features of glycogen (liver & skeletal muscle)

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

18

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

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

19

Digestion of Carbs in the mouth?

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

20

Digestion of carbs in the stomach?

S: stomach acid inactivates salivary enzymes

DF: DF not digested, delays gastric emptying

21

Digestion of starch carbs in SI?

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)

22

Digestion of Dietary Fibre in SI and LI

SI: DF is not digested, delays absorption

LI: bacterial enzymes digest DF into SCFA, gas

23

The steps of monosaccharide absorption?

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

24

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

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

25

What happens when storage of carbs runs out?

body protein > glucose
fat stores > ketones (ketosis)

26

Recommended servings of carbs a day

Preschoolers = 4
children = 5
adults = 6

27

Difference between intrinsic and free sugars?

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

28

Insoluble fibre?

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

29

Soluble fibre

-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

30

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

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

31

Recommended intakes of carbs

45-65% carbs
of this 10% simple sugars

15% > 5%

32

What happens when you have a high glycaemic Diet?

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

33

Why are people encouraged to eat things with a LGI?

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

34

Symptoms of lactose malabsorption?

bloating, abdominal discomfort, diarrhoea
as sugar overload disrupts the osmotic balance of LI

35

Primary Lactase deficiency? Management?

Genetically predisposed

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

36

secondary lactase deficiency?

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

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