Basic nutrition Flashcards

1
Q

main classes of nutrients

A
  • Essential
  • Non-essential
  • Macro
  • Micro
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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
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3
Q

non-essential nutrients

A
  • Can be made, and in sufficient quantities, in the body.

- E.g. Glucose

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4
Q

macrinutrients

A
  • Usually required in gram quantities
  • Carbohydrate, fat, protein, water, alcohol (essential??)
  • Quantitatively largest part of diet
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5
Q

micronutrients

A
  • Usually needed in small amounts (<1 g)
  • Vitamins, minerals (5 major), trace-elements
  • Quantitatively largest family of nutrients
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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

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7
Q

types of saccharide

A
  • Monosaccharide
  • Disaccharide - 2 sugars
  • Polysaccharide - many monomers with chains
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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)
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9
Q

glucose

A

Honey
Sugar
Confectionary

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10
Q

fructose

A

Honey
Fruit
Some veg
Corn starch

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11
Q

galactose

A

Lactose from milk

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12
Q

sucrose

A

Sugar beet
Sugar cane
Molasses
Syrup

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13
Q

lactose

A

milk

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14
Q

maltose

A

Wheat

Barley

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15
Q

oligosaccharide

A

Leeks
Onions
Lentils
Beans

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16
Q

starch

A

Potatoes
Cereals
Beans

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17
Q

dietary fibre

A

Cellulose

Non-cellulose

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18
Q

cellulose

A

Plant cell walls, resistant to digestion

insoluble - absorbs water

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19
Q

non-cellulose

A

Petins, gums, glucans

soluble in water

forms gel in gut

slow down absorption nutrients

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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

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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

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22
Q

other fats

A
  • Phospholipids

- Sterols

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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
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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
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25
Q

dietary fats

A
  • Short chain SFA (C4-C10)
  • SFA (C14-C18)
  • MUFA, especially C18:1
  • PUFAs, n-6
  • PUFAs, n-3
  • Cholesterol
  • Phospholipids
  • Trans-fats
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26
Q

short chain SFA

A

Milk
Milk products
Butter

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27
Q

SFA (c14-18)

A

Meat
Animal foods and fats
Coconut and palm oils

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28
Q

MUFA

A

Olive and rapeseed oils

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29
Q

PUFAs, n-6

A

Linoleic:

Sunflower and soyabean oil, meat, eggs and nuts

30
Q

PUFAs, n-3

A

Eicosapentanoic acid and docosahexanoic acid: Oily fish

31
Q

cholesterol

A

Foods of animal origin
Eggs
Organ meats

32
Q

phospholipid sources

A

Animal foods

Eggs

33
Q

trans-fats

A

Ruminant animals

Hydrogenated fats in manufactured goods

34
Q

protein

A

• 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
Q

what is protein used for?

A
  • Energy
  • Structural material for all tissues
  • Enzymes, carrier molecules, hormones, receptors, neurotransmitters,
    clotting factors
36
Q

how is quality of protein classified?

A

• 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
Q

essential AAs

A
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
38
Q

non-essential AAs

A
Alanine
Arginine
Aspartate
Asparagine
Cysteine
Glutamate
Glutamine
Glycine
Proline
Serine
Tyrosine
39
Q

main functions of food

A
  • Promotion of growth and development
  • Provision of energy, warmth and movement
  • Resisting and fighting infection
  • Regulation of metabolism
40
Q

promotion of growth and development

A
  • 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
Q

provision of energy, warmth and movement

A

Mainly performed by carbohydrates and fats

42
Q

resisting and fighting infection

A

Mainly performed by vitamins, minerals, and protein

43
Q

regulation of metabolism

A

Enzymes are proteins, and require co-factors of vitamins and minerals to function

44
Q

Committee on Medical Aspects (COMA) of Food Policy 1991

A
  • 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
Q

DRVs

A

see notes

46
Q

what should be on your plate?

A
  • 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
Q

sections of eatwell plate

A
Fruit and veg
Bread, rice, pasta and potatoes
Milk and dairy
Meat, fish, eggs, beans
Foods high in fat and sugar
48
Q

evolution of the modern diet

A

see notes

49
Q

simple sugars

A
  • Chains of 3-7 C atoms, w/ H and O in ration 2:1

- Glucose - most common - C6H12O6

50
Q

kinds of carbohydrates

A
  • 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
Q

glycogenolysis

A

Reconverts glycogen to glucose

52
Q

gluconeogenesis

A

Synthesises glucose from C skeletons of AAs

53
Q

fibre

A

Resists human digestive enzymes

54
Q

basic starch configurations

A
  • Amylose - long, straight chain glucose units

- Amylopectin - highly branched mono linkage

55
Q

lipids

A
  • C, H, and O
  • Higher ratio H
  • 1 glycerol and 3 FAs
56
Q

categories of lipids

A
  • Simple (glycerol and 3 FAs)
  • Compound (phospholipids, glycolipids and lipoproteins) - simple combined with other chems
  • Derived (cholesterol) - simple + compound
57
Q

where are saturations FAs found?

A

Animal meat
Egg yolk
Dairy fats
Cheese

58
Q

how much of total energy intake does lipid provide?

A

36%

59
Q

what vitamins fo lipids transport

A

A, D, E, K

60
Q

why do proteins differ chemically from lipids and carbohydrates?

A

Contain N (+sulfur, phosphorous and iron)

61
Q

how many AAs are essential

A

8/20

62
Q

what are proteins with essential AAs called?

A

Complete proteins (higher quality)

63
Q

examples fo complete proteins

A
Egg
Milk
Cheese
Meat
Fish
Poultry
64
Q

how do DRIs differ from RDAs?

A

Focus on promoting health maintenance and risk reduction for nutrient-dependent diseases rather than traditional criterion of preventing deficiency diseases

65
Q

what do DRI values include?

A
  • RDAs, EARs, AIs, ULs
  • Recommendations that apply to gender and life stages of growth and development based on age and pregnancy and lactation
66
Q

EAR

A

Estimated average requirements (EAR).

- Predicted adequate for 50% of people within a given age group

67
Q

RDA

A

Recommended dietary allowance (RDA).

- Sufficient to meet the needs of 97.5% of health individuals within a given age and sex group.

68
Q

AI

A
Adequate intake (AI).
- No RDA available but an estimate generated for all individuals.
69
Q

UL

A

Tolerable upper intake levels (UL).

- Aimed to prevent excessive intake known to be harmful.

70
Q

AMDR

A

Acceptable macronutrient distribution ranges (AMDR).

- A range of intakes expressed as percentage of total energy intake

71
Q

what is a requirement?

A

Minimum amount of a nutrient needed to sustain a physiological state, function, or structure of an organism