NFS284 Carb 1 Flashcards
Classification of CHO - Degree of processing - Chemical structure - Digestion and absorption
1
Q
Disappearance data
A
Data about the market
2
Q
Disappearance data does not represent…
A
Intake levels
Only information about how much is in market, but not how much consumed
3
Q
3 ways in which we classify carbs
A
- Chemical composition
- Physiological impact
- Degree to which they have been processed
4
Q
Where can chemical composition of carbs be found
A
Nutrition facts table
5
Q
Physiological impact of carbs is divided into…
A
- Digestibility
2. Glycemic index
6
Q
Processing of carbs is divided into…
A
- whole foods
2. refined food
7
Q
Green revolution
A
Development of crops that are drought resistant, salt resistant, etc.
Increased production of cereals
8
Q
When did human population increase?
A
Agricultural revolution
9
Q
Agricultural revolution
A
We started growing grains
10
Q
What caused the drastic increase in human population?
A
Green revolution
11
Q
What is the perception associated with “whole foods”? Is this right?
A
They are in natural state
No, most things are processed (not necessarily bad)
12
Q
What is the perception associated with refining carbs? Is this right?
A
Separates carbs from their vitamins, minerals, fibre.
No, refining does not always mean removing
13
Q
Processing / refining
A
Changing food in some way;
Process which change or remove various components of food
14
Q
CFG recomend we eat more ____ carbs
A
unrefined
15
Q
__% of energy in Canadian diet is added sugars
A
13%
16
Q
Is the 13% of added sugars in diet a bad thing? What did the study show?
A
At 13% of added sugars, intake of healthy nutrients are the highest
17
Q
The global recommendation to have less sugar as possible…good or bad?
A
Not necessarily bad to have our current intake of sugars because we are getting the best intake of good minerals along with those sugars.
18
Q
What is something that you have to be wary of when examining data with sugars?
A
Milk sugars (is it included or not?)
19
Q
When are sugars just empty calories?
A
In drinks
20
Q
Whole / unrefined grains contain…
A
- Bran layer
- Endosperm
- Germ
21
Q
Bran layers
A
Source of fibre and vitamins
Hard layer to protect the embryo (germ)
22
Q
Germ
A
Source of vegetable oils and vit E
The embryo of the plant
Contains lots of protein & nutrients
23
Q
Endosperm
A
Contains starch and some protein
Main energy store
24
Q
What is removed from grain during refining?
A
- Bran
- Germ (maybe)
25
Regulation for refined grains in Canada...
1. Enriched
| 2. Fortified
26
Enrich
Replace nutrients that you removed (not over)
27
What are grains usually enriched with?
Thiamin
Riboflavin
Niacin
Iron
28
What are grains usually fortified with?
Folate
29
Fortify
Putting more than what would be present
30
Why are some foods fortified?
Public health reasons (prevent some kind of disease)
31
Which nutrients are lost during grain refining?
Magnesium
Vit E
Vit B6
...
32
What does folate do for humans?
Prevent neural tube defects
33
How to determine if a product is whole grain?
1. "whole grain" listed in ingredients (first or second) and label
2. Whole grain stamp
34
CFG recommends that ___ of grain servings be whole grains
half
35
How is whole grain products made?
During processing, grain is grinded separately and added back together after
36
Basic whole grain stamp
Products may contain some refined grain
| At least 51%
37
100% whole grain stamp
All grain ingredients are whole grains
38
Unrefined carbs are ____ more healthy.
| Refined carbs are ____ less healthy.
Sometimes
39
When are added sugars good / bad?
- Aid consumption of healthy nutrients
| - Consumed alone or in excess
40
What part of the plant uses energy to make glucose?
Chlorophyll
41
Photosynthesis
CO2 + water -> oxygen + glucose
42
Chemical classification of carbs
1. Simple carbs
| 2. Complex carbs
43
Simple carbs
- Sugars (short chain)
- Sometimes refined
- High GI starches
44
Complex carbs
- Starches and fibres (long chain)\
- Sometimes unrefined
- "natural" sugars
45
Is the terminology for chemical classification good?
No, too ambiguous.
| Be specific and define when using these terms.
46
Carbs in the diet are classified as...
1. Sugars
2. Oligosaccharides
3. Polysaccharids
47
define: sugars
mono & di-saccharides
48
define: oligosaccharides
3-9 units
49
define: polysaccharides
>10 units
Starch
Dietary fibre
50
Common monosaccharides?
- Glucose
- Galactose
- Fructose
51
Where do we find glucose in foods?
Fruits
Vegetables
High fructose corn syrup
52
HFCS
high fructose corn syrup
53
What is HFCS?
Corn syrup converted to -> glucose converted to-> fructose
| 50:50 glucose:fructose
54
Where do we find galactose in foods?
Free galactose not found in foods
55
Corn syrup
When you hydrolyse starch
56
Where do we find fructose in foods?
Fruits
Vegetables
HFCS
57
How do we form longer chains of sugars?
Condensation
58
How do we break up sugar chains?
Hydrolysis
59
Major dissaccharides in out diet
1. Sucrose
2. Maltose
3. Lactose
60
Sucrose is made up of...
Fructose + glucose
61
Maltose is made up of...
Glucose + glucose
62
Lactose is made up of...
Glucose + galactose
63
Source of sucrose
Fruits
Vegetables
Table sugar
64
Source of maltose
Germinating seeds
| Starch digestion
65
Source of lactose
Milk (products)
66
3 main polysaccharides
1. Glycogen
2. Starch
3. Fibre
67
Glycogen
Carb storage in animals
68
Glycogen is found in...
liver (regulated release into bloodstream)
| muscle (used as energy)
69
How much glycogen is in liver?
100-200 g
70
How much glycogen is in muscle?
200-300 g
71
What is glycogen stored with?
water (1g glycogen - 5~10g water)
72
Is glycogen found in foods?
no
73
Starch
Energy store in plants
74
Is starch found in foods?
Yes
75
2 forms of starch
1. Amylose
| 2. Amylopectin
76
Amylose
Glucose units stuck together in a straight line (a-helix).
| Different strands H bond with each other-> hard to digest
77
Amylopectin
Branched structure
| Easy to digest
78
Raw starch is packed in...
granules
79
Granules in plants
semi-crystalline structures that are resistant to digestion
80
___ starch is resistant to digestion
raw
81
Define: gelatinization
| Why is is used?
Cooking starch in moist heat
| Used to make starch easier to digest
82
Process of gelatinization
Starch granules swell with water
Disrupted crystalline structure
Molecules of starch become tangled -> viscous
83
Define: retrogradation
Cooling starch that has been gelatinized
84
What does retrogradation doe to GI?
Brings it down
85
Process of retrogradation
Molecules of starch partially re-associate
| Starch is less digestable
86
Dietary fibre
Polysaccharides and lignin not digested by human enzymes found intact in plant foods
87
Fibre
Undigestable carb
88
Functional fibre
ISOLATED indigestible carbohydrates shown to have BENEFICIAL physiological effect in humans
- can be man made or natural
89
Categories of fibre
1. dietary fibre
2. functional fibre
3. Soluble fibre
4. insoluble fibre
90
Total fibre
Sum of dietary + functional fibre
| Seen on food label
91
Soluble fibre
Dissolves in water or absorbs water to form viscous solutions
92
Soluble fibres are usually broken down by...
colonic micro-organisms
93
Examples of soluble fibre
- pectin
- gums
- hemicellulose (some)
94
Insoluble fibre
Does not dissolve in water
95
Digestion of insoluble fibres?
Incompletely fermented in the colon
96
Examples of insoluble fibre
- cellulose
- hemicellulose (some)
- lignin
97
Digestibility is categorized into...
1. available CHO
| 2. Unavailable CHO
98
available CHO
can be absorbed in small intestines
99
unavailable CHO
not absorbed in small intestines; enters the colon (e.g. fibre)
100
GI
extent to which available CHO raises blood glucose relative to an equal amount of glucose.
How fast blood glucose levels rise after eating a food.
101
Chemical categorization of sugars does not predict...
physiological impact
102
salivary amylase breaks down...
CHO -> maltose
103
Most important role of salivary amylase
Taste
104
Amylase is made by...
pancreas
105
Insulin is made by...
pancrease
106
Digestion of available CHO
1. Mouth (salivary amylase)
2. Stopped in stomach
3. Pancreas (amylase)
4. Small intestines
107
Amylase breaks down...
starch -> oligosaccharides + maltose
108
Brush border enzymes break down...
oligosaccharides + disaccharides -> monosaccharides
109
Only __ can be absorbed
monosaccharides
110
Brush border enzymes for digesting CHO
sucrase
lactase
maltase
111
Lactose intolerance
Low levels of lactase
Undigested lactose -> large intestines
Causes pain, gas, diarrhoea
112
Treatment for lactose intolerance
Cheese low in lactose
Lactose free (lactase put in already)
Non-dairy substitutes
113
Lactose intolerance more common in...
non-white people
114
CFG recommends __ servings of milk per day
2-3
115
Getting calcium from things other than milk
1. small portions of milk throughout the day
2. tofu, fish, veggies (broccoli)
3. calcium fortified foods
116
Digestion of unavailable CHO
1. Colon
2. Fermentation by micro-organisms (secrete enzymes)
3. Sugars taken up by micro-organism (used for glycolysis)
117
Byproducts of fermentation
gases (H, CO2, methane)
| short-chain FA (acetate, propionate, butyrate)
118
Purpose of inulin
Feed micro-organisms
119
Glucose has GI of...
100
120
GI may vary even when...are similar
CHO levels
121
What causes differences in blood glucose response when ingesting food?
1. Nature of monosaccharide
2. Amount consumed
3. Rate of absorption
122
GI tells you about...
quality of carbohydrate
123
What type of monosaccharide tends to cause high GI? Low GI?
Glucose (because we we are looking at blood glucose...)
| Fructose (not glucose)
124
Calculate glycemic load
GL = gram x GI/100
125
Low GI
<55
126
High GI
>71
127
Low GL
>= 10
128
Calculate GI
GI = 100 x food/glucose
129
Difference between GI and GL
```
GI = qualitative (amount of food doesn't matter)
GL = quantitative (both amount and quality)
```
130
Drawback of GI?
Independent of amount
131
Unit of GL?
gram
132
1 g GL =
glycemic impact of 1g glucose
