Basic nutrition Flashcards
(71 cards)
1
Q
main classes of nutrients
A
- Essential
- Non-essential
- Macro
- Micro
2
Q
essential nutrients
A
- Cannot be synthesised (or not in sufficient quantities) by the body.
- Vitamins, minerals, essential fatty acids, essential amino acids
- Need to be taken in
3
Q
non-essential nutrients
A
- Can be made, and in sufficient quantities, in the body.
- E.g. Glucose
4
Q
macrinutrients
A
- Usually required in gram quantities
- Carbohydrate, fat, protein, water, alcohol (essential??)
- Quantitatively largest part of diet
5
Q
micronutrients
A
- Usually needed in small amounts (<1 g)
- Vitamins, minerals (5 major), trace-elements
- Quantitatively largest family of nutrients
6
Q
carbohydrates
A
- Carbo- (carbon)
- -hydrate (water; hydrogen and oxygen)
• Hydrated carbons (CH2O)
- Organic compounds
• Glucose C6H12O6 - like branched starch
- Exists in solution predominately cyclical as pyranose
7
Q
types of saccharide
A
- Monosaccharide
- Disaccharide - 2 sugars
- Polysaccharide - many monomers with chains
8
Q
dietary carbohydrates
A
- Glucose (most common sugar in body)
- Fructose (cheaper than sucrose)
- Galactose (neural tissue development)
- Sucrose (commonest in diet)
- Lactose (widely used in food industry)
- Maltose (fermented to make beer!!)
- Oligosaccharide (<10 monosaccharides, rapidly fermented in colon!)
- Starch (amylopectin:amylase, 3:1)
- Dietary fibre (non-starch polysaccharide)
9
Q
glucose
A
Honey
Sugar
Confectionary
10
Q
fructose
A
Honey
Fruit
Some veg
Corn starch
11
Q
galactose
A
Lactose from milk
12
Q
sucrose
A
Sugar beet
Sugar cane
Molasses
Syrup
13
Q
lactose
A
milk
14
Q
maltose
A
Wheat
Barley
15
Q
oligosaccharide
A
Leeks
Onions
Lentils
Beans
16
Q
starch
A
Potatoes
Cereals
Beans
17
Q
dietary fibre
A
Cellulose
Non-cellulose
18
Q
cellulose
A
Plant cell walls, resistant to digestion
insoluble - absorbs water
19
Q
non-cellulose
A
Petins, gums, glucans
soluble in water
forms gel in gut
slow down absorption nutrients
20
Q
fats
A
• Triacylglycerol comprises up to 95% of dietary fats
• Contain three fatty acids attached to a molecule of glycerol
• Concentrated source of energy, usually stored within adipose tissue
• Insulating layer under the skin
• Vehicle for intake and absorption of
fat soluble vitamins
• Contributor to flavour and palatability of foods
- C, H and O - less H - energy dense
21
Q
FAs
A
• Organic chains of C, H, and O
• Categorised based on the number and bonding of carbon atoms
• Saturated (0 double bonds) - packed tightly - solid - less healthy - make cell membranes not work as well
• Monounsaturated (1 double bond)
• Polyunsaturated (>1 double bond)
- Unsaturated - less dense - liquid
• n = omega = number of carbons from methyl end - first double bond - give diff properties
- Less than or equal to 6 - short chain, 6-12 = medium, more than 12 = long
- Oleic acid = olive oil
- Lipoproteins circulate in blood and carry fat - proteins on outside that tell molecule where to go
22
Q
other fats
A
- Phospholipids
- Sterols
23
Q
phospholipids
A
- Contain glycerol backbone with two fatty acids (non-polar) and ‘polar head group’ with a phosphoric acid residue and either sugars or amino acids
- Amphipathic acting as interface between aqueous and lipid environments, therefore essential structural components of cell membranes (phospholipid bilayer)
- Hydrophobic tails and hydrophilic heads make bilayer
24
Q
sterols
A
- Arranged in a ring structure with associated side chains
- Cholesterol is main sterol, often associated with a fatty acid to form a cholesteryl ester
- Plays a key role in membrane structure, synthesis of hormones, and bile acids
- Lipoproteins characterised by types and amount of cholesterol
25
dietary fats
- Short chain SFA (C4-C10)
- SFA (C14-C18)
- MUFA, especially C18:1
- PUFAs, n-6
- PUFAs, n-3
- Cholesterol
- Phospholipids
- Trans-fats
26
short chain SFA
Milk
Milk products
Butter
27
SFA (c14-18)
Meat
Animal foods and fats
Coconut and palm oils
28
MUFA
Olive and rapeseed oils
29
PUFAs, n-6
Linoleic:
Sunflower and soyabean oil, meat, eggs and nuts
30
PUFAs, n-3
Eicosapentanoic acid and docosahexanoic acid: Oily fish
31
cholesterol
Foods of animal origin
Eggs
Organ meats
32
phospholipid sources
Animal foods
| Eggs
33
trans-fats
Ruminant animals
| Hydrogenated fats in manufactured goods
34
protein
• Composed of carbon, hydrogen, oxygen AND nitrogen - mainly excreted in urine and used to calculate protein requirements
- (NB nitrogen mainly excreted in urine as urea and can be used to calculate protein requirements)
• Made up of amino acids in polypeptide chains, which are digested and used throughout the body.
35
what is protein used for?
- Energy
- Structural material for all tissues
- Enzymes, carrier molecules, hormones, receptors, neurotransmitters,
clotting factors
36
how is quality of protein classified?
• Quality of protein classified on digestibility (poor for plants) and nitrogen retention (poor for plants) to give a biological value
- Retained/Absorbed x 100
- Egg protein is 100, beef and fish are 75
- Above 70 is considered to reflect protein quality sufficient to
maintain growth
37
essential AAs
```
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
```
38
non-essential AAs
```
Alanine
Arginine
Aspartate
Asparagine
Cysteine
Glutamate
Glutamine
Glycine
Proline
Serine
Tyrosine
```
39
main functions of food
* Promotion of growth and development
* Provision of energy, warmth and movement
* Resisting and fighting infection
* Regulation of metabolism
40
promotion of growth and development
- Mainly performed by proteins
- Muscle, soft tissues and organs consist largely of protein and are constantly turning over
- Calcium and phosphorus building blocks of skeleton, dependent upon vitamin D
- Iron component of red blood cells, mitochondria
41
provision of energy, warmth and movement
Mainly performed by carbohydrates and fats
42
resisting and fighting infection
Mainly performed by vitamins, minerals, and protein
43
regulation of metabolism
Enzymes are proteins, and require co-factors of vitamins and minerals to function
44
Committee on Medical Aspects (COMA) of Food Policy 1991
* Report of the Panel on Dietary Reference Values (DRV) assessed requirements of around 40 nutrients
* Distribution of requirements in a group of individuals for a nutrient was assumed to be normally distributed
* This gives a notional mean requirement, or Estimated Average Requirement (EAR)
* Reference Nutrient Intake (RNI) is 2 notional standard deviations above the EAR
* 2 std dev below the mean is the lower RNI (LRNI). Intakes below this line are likely deficient for most individuals.
45
DRVs
*see notes*
46
what should be on your plate?
* All nutrients listed in DRV tables
* Supports health, work and leisure
* Provides sufficient reserve to protect during times of illness or deficiency
* Some protection from disease
47
sections of eatwell plate
```
Fruit and veg
Bread, rice, pasta and potatoes
Milk and dairy
Meat, fish, eggs, beans
Foods high in fat and sugar
```
48
evolution of the modern diet
*see notes*
49
simple sugars
- Chains of 3-7 C atoms, w/ H and O in ration 2:1
| - Glucose - most common - C6H12O6
50
kinds of carbohydrates
- Monosaccharides (glucose and fructose)
- Disaccharides (2 mono in sucrose, lactose and maltose)
- Polysaccharides - 10+ simples sugars - starch and fibre in plants and glycogen in animals
51
glycogenolysis
Reconverts glycogen to glucose
52
gluconeogenesis
Synthesises glucose from C skeletons of AAs
53
fibre
Resists human digestive enzymes
54
basic starch configurations
- Amylose - long, straight chain glucose units
| - Amylopectin - highly branched mono linkage
55
lipids
- C, H, and O
- Higher ratio H
- 1 glycerol and 3 FAs
56
categories of lipids
- Simple (glycerol and 3 FAs)
- Compound (phospholipids, glycolipids and lipoproteins) - simple combined with other chems
- Derived (cholesterol) - simple + compound
57
where are saturations FAs found?
Animal meat
Egg yolk
Dairy fats
Cheese
58
how much of total energy intake does lipid provide?
36%
59
what vitamins fo lipids transport
A, D, E, K
60
why do proteins differ chemically from lipids and carbohydrates?
Contain N (+sulfur, phosphorous and iron)
61
how many AAs are essential
8/20
62
what are proteins with essential AAs called?
Complete proteins (higher quality)
63
examples fo complete proteins
```
Egg
Milk
Cheese
Meat
Fish
Poultry
```
64
how do DRIs differ from RDAs?
Focus on promoting health maintenance and risk reduction for nutrient-dependent diseases rather than traditional criterion of preventing deficiency diseases
65
what do DRI values include?
- RDAs, EARs, AIs, ULs
- Recommendations that apply to gender and life stages of growth and development based on age and pregnancy and lactation
66
EAR
Estimated average requirements (EAR).
| - Predicted adequate for 50% of people within a given age group
67
RDA
Recommended dietary allowance (RDA).
| - Sufficient to meet the needs of 97.5% of health individuals within a given age and sex group.
68
AI
```
Adequate intake (AI).
- No RDA available but an estimate generated for all individuals.
```
69
UL
Tolerable upper intake levels (UL).
| - Aimed to prevent excessive intake known to be harmful.
70
AMDR
Acceptable macronutrient distribution ranges (AMDR).
| - A range of intakes expressed as percentage of total energy intake
71
what is a requirement?
Minimum amount of a nutrient needed to sustain a physiological state, function, or structure of an organism
