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Macronutrients
Unit 2: Applying the principles of nutrition to a physical activity programme
Session
Aims
To understand the principles of nutrition in relation to the macronutrients
Learning Objectives
By the end of the session the learner will
• be able to describe the function and metabolism of macronutrients
• be able to explain the main food groups and the nutrients they contribute to the diet
• be able to explain the relationship between nutrition, physical activity, body composition and health including:
• links to disease/disease risk factors• cholesterol• types of fat in the diet
Protein
The structure of protein:
• proteins are made from molecules or building blocks called
amino acids
• there are 20 amino acids available from the natural diet
• the body uses these amino acids to build and repair the many proteins from which we are comprised
Peptides
Free amino acid
Dipeptide
Oligopeptide
Polypeptide
Amino Acids
Essential amino acids • these are the 9 amino acids which the body is unable to
synthesise it’s self
Amino Acid
HistidineIsoleucineLeucineLysine
MethioninePhenylalanine
ThreonineValine
Tryptophan
Amino Acids
Non - essential amino acids • these are the 11 amino acids which the is able to synthesize
when sufficient essentials are ingested
Conditionally essential amino acids
Glycine Alanine Tyrosine Serine Cysteine Proline
Glutamic acid Glutamine Aspartic acid Asparagine Arginine
Complete proteins
• these are protein foods which contain all 9 essential amino acids in sufficient amounts
Complete proteins
Animal sources
Non-animal sources
eggs meat poultry dairy fish
soy foods buckwheat quinoa
Incomplete Proteins
• these are always plant foods
• plant foods are mostly made from carbohydrate however, they also contain some amino acids and therefore, protein
• These are deficient in one or more amino acidse.g. beans or pulses are deficient in methionine
• plant foods therefore, have a lower biological availability
Complementing Proteins
Combining suitable incomplete protein foods together in the diet can provide the full range of essential amino acids
Rice and pulses
Vegetables and seeds
Vegetables and nuts
Grains and pulses
Protein Task
Identify from the following list which foods are complete proteins and which are incomplete proteins
egg lentils mackerel
soy beans cheese oats
chick peas beef tofu
liver olives buck wheat
Protein: Functions
Proteins have 3 basic functions in the human body
Structural – collagen, muscle, skin
Homeostatic – hormones, immunity
Fuel - back up to carbohydrates and fats
Protein: Catabolism
• described as the breaking down of large structures into smaller structures
• an example is the breakdown of a protein into individual amino acids
SS
SS
Protein Amino acids
Catabolism
Protein: Anabolism
Described as a building up of smaller structures into larger structures
Amino Acids
Amino acids used to repair muscle
Amino acids used to build other key proteins
Protein Requirements Task
How much? Depends on activity levels/type and body size
Determine your grams of protein per kilogram of bodyweight
RDA sedentary adult : 0.8
Recreational exerciser 0.8 -1.5
Endurance athlete: 1.2 - 1.6
Teenage athlete 1.5 - 2.0
Adult building muscle mass 1.5 - 1.7
Estimated upper limit 2.0
Carbohydrates Structure
monosaccharide
‘Single sugar’
Fructose
Galactose
Glucose
=Sucrose Fructose + Glucose
=Galactose + GlucoseLactose
Maltose =Glucose + Glucose
disaccharide
‘double sugar’
They consist of a glucose molecule joined to another saccharide
Carbohydrates Structure
Monosaccharides and disaccharides
simple sugars
Fruit - healthy option
• natural produce with sugars packaged within
• contain vitamins and minerals assist metabolise the CHO as energy
• contain fibre
Sources - Simple Sugars
Monosaccharides and disaccharides
simple sugars
Unhealthy sources of refined sugar
• white refined sugar added
• no vitamins or minerals to utilise the energy
• lack fibre
• anti-nutrient: draws on nutrient stores to metabolise food
Sources - Simple Sugars
Complex Carbohydrates
Starch
Larger molecules made comprising of the monosaccharides
Glucose
Fructose
Galactose
Multiple molecules of glucose are called polysaccharides
Sources of unrefined carbohydrate Properties
• wholemeal or whole grain products• whole grain rice• frozen vegetables• fresh vegetables• sweet potatoes• yams• pulses• quinoa
• source of energy• good source of dietary fibre• good source of vitamins and minerals• slower, sustained insulin response
Sources of refined carbohydrate Properties
• white bread• white pasta• cakes, biscuits and pastries• rice cakes• CHO content of processed foods• white rice
• source of energy• deficient in dietary fibre• largely stripped of their vitamin and
mineral content• produces faster insulin response
CHO Task
Identify which of the following foods contain simple or complex carbohydrates
Additionally identify which are refined or unrefined foods
wholemeal bread maple syrup mango
honey French fries lentils
pasta ice cream doughnut
chocolate cornflour banana
Fibre
Definition:
Fibre is indigestible plant material or the parts of unrefined carbohydrate foods which we are unable to digest as we lack the necessary enzymes
Soluble fibre
• dissolve in water• found in the inside of the
plant
• fruit• broccoli• pulses• oats• barley
Fibre
Fibre
Insoluble fibre
• does not dissolve in water• found in the outer skin of
plants or fruits
• fruit skins• veg skins• outer coating of grains
Fats: Key Functions• formation of virtually all cell membranes
• formation of myelin sheath within the nervous system
• synthesis of steroid hormones
• assists in the regulation of enzymes
• insulation through subcutaneous adipose tissue
• protection of internal organs
• transportation, storage and utilisation of fat soluble vitamins A, D, E, K
• fuel source during lower intensity work loads
• storage of energy within the adipose tissue
Triglycerides
This is the type of chemical structure most fats exist in naturally
TriglyceridesG
lyce
rol
Fatty acids occur
naturally in groups of
three
A triglyceride is simply three fatty acids attached to a carbohydrate back bone called glycerol
Saturated fats can pack closely together and are hard at room temperature
Saturated Fat
Saturated fat
Saturated fat Saturated fat
Saturated fat
Saturated fat Saturated fat
Saturated fat
What are naturally occurring sources of fat?
Common sources of saturated fat
Animal Non animal
meat – beef, pork, lamb, venison poultry – chicken, duck dairy – milk, cheese, yoghurt, cream, butter eggs
palm oil coconut oil
Saturated Fat
Some Functions of Saturated Fat
• effective immune function
• protects the liver from alcohol, pesticides and other toxins
• provision of energy
• antimicrobial properties – fight harmful micro-organisms in our digestive tract
Unsaturated Fats
• carbon chain is not completely full of hydrogen atoms
• these ‘gaps’ in the chain make the fatty acids more able to react
• a double bond causes a bend in the molecule
UNSATURATED FATTY ACID
Double bond
Monounsaturated Fats
• have a single double bond in the carbon chain – one bend
• liquid oils at room temperature
Sources:
Peanut oil
Rapeseed oil(LEAR)
Olive oil
Avocado oil
Monounsaturated Fats
• have many health promoting benefits for the body
• helps to keep arteries clean and free from plaques
Polyunsaturated Fats
• several double bonds along the carbon chain – several bends in the molecule
• different shapes again mean different functions
POLYUNSATURATED FATTY ACID
Double bond
Double bond
Polyunsaturated Fats
• several double bonds along the carbon chain – several bends in the molecule
• different shapes again mean different functions
Sources:
Sunflower oil Vegetable oil Safflower oil Corn oil
Soya bean oil Rapeseed oil(original seed)
Essential Fatty Acids
All EFA’s are polyunsaturates!!
The name ‘essential can be misleading!!
Implies we need this more than other fats
EFA’s are vital, but only in small amounts for good health
Essential Fatty Acids
• must be ingested in the diet - we cannot synthesize them
• categorised as:
Omega 3 Omega 6
Cod liver oil
Linseeds Organic eggs
Sunflower oil Vegetable oil
Safflower oil Corn oil
Identify from the following list the dominant type of fat found in each food product and in those that are polyunsaturated whether it is omega 6 or omega 3 dominant
chicken butter flaxseed
herring olive oil margarine
pork vegetable oil coconut
salmon beef peanuts
Fats Task
• sunflower or vegetable margarines are solid at room temperature!
• manufacturers change the properties and consistency of oils to increase marketability
Margarines
Hydrogenation
Oils with catalyst subjected to hydrogen gas in a high-
pressure, high-temperature reactor.
Oils mixed with a nickel
catalyst
Oils, now rancid, steam cleaned to remove all vitamins & anti-oxidants (but pesticides
and solvents remain!)
Soy beans, corn, cottonseed or
rapeseeds
Remaining fraction of oils removed with hexane and
other solvents
Oils extracted by high temperature & pressure
Soap-like emulsifiers mixed
in
Oil steam cleaned again to remove horrible odour
Gray colour removed by bleaching
Advertising promotes margarine
as a health food
Mixture is packaged in blocks
or tubs
Artificial flavours, synthetic vitamins and natural colour
added
Saturated Fatty Acid
Unsaturated Fatty Acid
Hydrogenation
Hydrogen attachesat the double bond
When fully hydrogenated the molecule becomes a straight saturated fatty acid
Hydrogenation
• oils are only partially hydrogenated, so that some fatty acids remain unsaturated
• this allows them to still market it as a polyunsaturated spread!
Trans Fats
• during hydrogenation, the double bonds not saturated by hydrogen are still affected
• a hydrogen atom flips to the opposite side of the double bond altering the molecular shape
Straight, unsaturated fatty acid!!
Natural fats contain maximum of 2% trans fatty acids
Hydrogenated oils may contain up to 50 – 60% trans fatty acids
Trans Fats
• linked to a deterioration in blood lipids profiles and heart disease
• implicated in increased insulin resistance – type 2 diabetes
• implicated in causing cancer, obesity and bone loss
Trans Fats
Sources:
• 80% of all hydrogenated oils are Soy
• biscuits and cakes
• sweet and savoury sauces and syrups
• pies and pastries
• take away meals
• boxed meals and TV dinners
• ice creams
Cholesterol
Cholesterol
Membrane formation
Steroid hormones
Bile saltsVitamin D
Synthesis75-80%
Diet20-25%
Lipoproteins
• liver is the control centre for fats - it can increase or decrease cholesterol synthesis according to needs
TG
Chol / TG
VLDL
Chol
LDL
‘mops up’HDL
Adipose
Cells
Cholesterol Levels
• total cholesterol will be measured
healthy < 5.0healthy upper limit 5.2
• identify LDL and HDL count
Healthy HDL at least 25%
Learning Check
Can the learner
• describe the function and metabolism of macronutrients
• explain the main food groups and the nutrients they contribute to the diet
• explain the relationship between nutrition, physical activity, body composition and health including:
• links to disease/disease risk factors• cholesterol• types of fat in the diet