chapter 4, CHO. Flashcards
(57 cards)
1
Q
how are CHO classified?
A
- the number of subunits
- the type of subunits presents.
2
Q
- what are the types of sugars?
- what is oligosaccharides?
- what are polysaccharides?
A
1.
- monosaccahrides
- disaccharides
2.
- few branches of many monosaccharides
3.
- 10 or more monosaccharides together
- also known as starch
3
Q
what are monosaccharides?
A
- a single sugar unit, that are building blocks of all CHO.
- absorbed directly into the bloodstream
4
Q
what are 3 types of monosaccharides?
A
- glucose
- galactose
- frutose
5
Q
3 functions of glucose in the body?
A
- cells use for energy
CNS fuel (brain used 20% OF BLOOD GLUCOSE as fuel) - stored as glycogen in muscle and liver for later use
- converted to fat and stored for energy
6
Q
what does fructose do?
A
- glucose is converted in the liver.
- directly absorbed into blood.
- does not generate insulin response.
7
Q
what is the glycemic index?
A
- a system ranking of CHO food on the affects of blood glucose levels.
- how fast it comes in
8
Q
what is high glycemic index vs low glycemic index?
A
HIGH GLYCEMIC
- greater than 70% of pure sugar
- absorb rapidly & digest
- large fluctuation in blood glucose and insulin levels.
LOW GLYCEMIC
- less than 55%
- usually their is a craving for sugar
- whole foods with high fibre.
- does not generate “rebound” with hypoglycaemia.
9
Q
what are factors of CHO food that affect the GI (glycemic index)?
A
- presence of high acidity, this helps keep GI low, by slow gastric emptying.
- presence of fat, high caloric intake slows emptying, absorption, and digestion.
- degree of cooking/ processing, when food is cooked or cut up into smaller pieces it increases the GI.
10
Q
what is glycemic loading?
A
- this is glycemic diet index as well as CHO quantity.
- this normally leads to fluctuating levels of blood glucose and insulin levels, which may cause someone to be insulin resistance.
11
Q
when 2 monosaccharides form a bond together, it is known as what?
A
- glycosidic bonds
12
Q
what are the 3 main nutrients of disaccharides?
A
- sucrose= glucose + frutose
- lactose= glucose + galactose
- maltose= glucose + glucose
13
Q
in disaccharides, what is the relative sweetness vs the GI in sucrose?
A
- relative sweetness is 100, the GI is 68.
- this means that sucrose has a low GI.
14
Q
in disaccharides, what is the relative sweetness vs the GI in lactose?
A
- relative sweetness is 15, the GI is 46.
- has a low GI
15
Q
in disaccharides, what is the relative sweetness vs the GI in maltose?
A
relative sweetness is 40, the GI is 105.
- this has a high GI bc it is 2 glucose molecules.
16
Q
what are characteristics of polyols sugars?
A
- no keynotes or aldehyde groups
- mildly sweet
- low caloric content
- does not stimulate insulin release
- limited absorption in GI tract
17
Q
what does FODMAP stand for?
A
- Fermentable Oligo-, Di-, Monosaccharides And Polyols
18
Q
what does FODMAP do?
A
- Short-chain carbohydrates (1-9 subunits) with limited
digestibility or absorption in small intestine
19
Q
FODMAP has 2 things that limit absorption, what are the 2 effects?
A
- osmotic effects (draw water into intestines)
- Pass undigested into colon / large intestine fermentation by
gut bacteria
Size of effect varies with type and amount consumed
20
Q
Restricting dietary intake of FODMAPs may improve / reduce
symptoms for people with?
A
- Functional Gastrointestinal
Disorders (FGIDs)
21
Q
- what are frutcans?
- what are prebiotics?
- what are galatcans?
A
- long chain of fructose molecules
- food that feeds good bacteria (probiotics)
- long chain of galactose molecules
22
Q
endurance athletes frequently experience _________ due to physical exertion alone?
A
gastrointestinal distress
23
Q
what are consequences of consuming high FODMAP CHO foods?
A
increase chances of GI distress
24
Q
polysaccharides can have what kind of shapes?
A
linear and branched
25
where do polysaccharide dietary sources come from?
primarly plant sourced.
26
what are the 2 types of plan sourced polysaccharides?
1. Startch (glucose chain used for energy)
2. fibre (health of GI tract)
27
how much CHO is stored in muscle and the liver?
. 80% in muscle, once the glucose is in the muscle in the form of glycogen it cannot be broken down and phosphorylated into the blood stream.
- 20% in liver. This glucose can phosphorylate in the liver into the blood stream which the brain can then use for energy in order to funcation.
28
what are the 2 types of starches?
1. amylose
2. amylopectin
29
1. what is amylose?
2. what is amylopectin?
1. AMYLOSE
- more resistant to enzymatic breakdown.
- low glycemic index
- cooking and cooling increases resistance starch levels.
2. AMYLOPECTIN
- more accessible for enzymatic breakdown
- high glycemic index
30
what are the important roles that fibre plays in human health?
- physical effects in GI tract
- some forms are fermentable prebiotics
- metabolize short chain fatty acids. can have an antimmflamatory response
31
1. what is soluble fibre?
2. what is insoluble fibre?
SOLUBLE FIBRE
- slows passage of food through the digestive tract.
- reduce cholesterol and LDL cholesterol.
INSOLUBLE FIBRE
- does not dissolve in water
- speeds passage of food through digestive tract.
32
what are the effects of excess fibre?
1. prebiotic effect of soluble fibre.
2. decreased mineral absorption
3. reduce absorption of fat soluble vitamins
33
what is a health benefit of consuming fibre?
- high fibre intake = low risk of disease. (obesity, insulin resistance, diabetes)
34
what is the recommended intake for fibre for male and female?
male 38g / day
female 25g/ day
35
what is the difference between good and bad CHO?
GOOD
- minimally processed
- fibre rich whole foods
- low GI
BAD
- high GI
- highly processed food
- low fibre, sugar rich
36
what is the difference between long and short term CHO
LONG TERM
- excess consumption can lead to obesity or
malnutrition
SHORT TERM
- ideal energy source for glycogen synthesis during /
after high-intensity physical activity -- rapidly digested, absorbed,
and metabolized
37
what enzymes help with the breakdown of CHO in the digestive system?
- salivary amylase
- pancreatic amylase
- brush boarder enzymes
- bacterial enzymes
38
what does villi and microvilli do?
- digestion occurs in the small intestine
- increase surface area for nutrient absorption
39
what causes damage to microvilli?
- osmatic stress
40
what are the 3 structures that make up the small intestine?
- duodenum
- jejunum
- ileum
41
1. CHO and protein has what ____% of digestion?
2. fat has what ______% of digestion?
1. 90%
2. 100%
42
what does 1. salivary amylase and 2. pancreatic do?
1. degrades starch to simpler disaccharides
2. hydrolysis of CHO in small intestine
43
what are the consequences for athletes with CHO digestion and absorption?
- damage to the brush border, cause damage to the villi and microvilli which makes it that CHO cannot be broken down.
44
what is SGLT?
sodium- glucose linked transporter
45
glucose transported into epithelial cells via_________?
SGLT
46
fructose uses what transport system in the body?
- passive facilitated diffusion.
47
glucose travels with Na+ down it's concentration gradient in what form of transportation?
- secondary active transport
48
CHO intake has 3 phases, what are factor considerations when making CHO intake recommendations?
- amount of CHO
- type of CHO
- meal size & frequency
- addition of other micronutrients.
49
what is the recommendation of total daily CHO intake?
3-12g/ kg
50
1. prior to training/ sport events, how long before the activity should an athlete consume CHO?
2. what are the goals of CHO intake prior to competition?
3. to avoid GI distress how much CHO should be consumed preceding the event?
1. 3-4hr before.
2. delay fatigue
- avoid hunger
- avoid GI distress
- prevent hypo hydration
3. 1-4g CHO/ kg per hour.
51
pre-event CHO intake enhances what?
liver glycogen stores.
52
during high intensity training or events, how much CHO should someone consume during the event?
- 30-60g CHO/ hr of activity
53
Na+ aid CHO absorption by what?
- SGLT transporter.
54
during high intensity activity, what happens to CHO when they are being consumed?
- the CHO goes into the liver where it is converted for energy to be used after the muscle glycogen has run out. for proper replacement of CHO it takes between 24-36 hours.
55
post exercise, for resynthesis to occur, what are 2 things that are depended on?
1. sufficient CHO intake
2. steady elevated insulin.
56
describe what happens in each of the 5 phases of CHO consumption post exercise/ activity?
1. timing
2. meal size/ frequency
3. type of CHO
4. amount of CHO
5. additional proteins
1. timing
- glycogen synthesis is maximized if CHO is
consumed as soon as possible post-activity
- optimal within 2hr.
2. meal size/ frequency
- Smaller, more frequent meals preferred
- insulin drive absorption of glycogen synthesis.
3. type of CHO
- High glycemic index foods favour glycogen synthesis
(insulin effect)
4. amount of CHO
- Within first hour: max. glycogen resynthesis with 1.5 g CHO / kg
5. additional proteins
- Some post-exercise protein may enhance glycogen synthesis
57
what are the pros and cons (different stages) of classic CHO loading?
PROS
- "Supercompensation” produces highest increase in muscle
glycogen relative to other methods
CONS
1. Depletion stage:
– irritability, hypoglycemia, fatigue, low energy, risk for injury
– inability to maintain training and conditioning
2. Repletion stage:
– gastrointestinal distress
