Nutrition
Nutrients
The building blocks of whole foods that have specific functions in the
body (1g = 17kj)
Energy, growth, maintenance and repairs
Micronutrients: needed in smaller quantities (vitamins and minerals)
Macronutrients: in large quantities (protein, carbs, lipids, water)
Macronutrients
Protein
Consist of chains of amino acids that form peptides and peptides
form proteins.
21 types of amino acids
Made up form atoms
Carbon
Hydrogen
Oxygen
Nitrogen (for growth and is only nutrient that contains it)
Sometimes: phosphorus, Sulphur and iron
Peptide bonds
AA: joined together into long chains = proteins
21 AA: from many different proteins
When amino acids link water molecule is taken away (condensation)
Reverse condensation: hydrolysis where water is added to protein
chains (during digestion)
2 AA: dipeptide and many AA: polypeptide
Essential amino acids
Cannot be produced by body and provided by food
8 essentials for adults and 10 for babies
Non-essential
Can be produced by body through rearrangements of elements
Complete proteins Incomplete proteins
Has essential amino acids Lack essential amino acids
High biological value (eggs, milk, Low biological value (rice, wheat
,meat, soya and fish) and maize)
Animal origins (soya beans is only Some foods of plant
1)
Functions
Forms all part of body cells, tissues, blood, enzymes, antibodies,
nails, skin, hair and some hormones
Growth repair and maintenance of body tissue
Maintain fluid balance in body
Supply energy if there is a shortage of carbs and fats (1g = 17kj)
Animal sourced protein Plant source protein
Meat / fish Legumes (beans, lentils etc.)
Poultry body tissues Seeds and nuts
Eggs and milk and milk products Cereal, veg and fruit (small
amount)
Protein deficiencies
Can stunt growth
Can cause oedema (imbalance of fluid)
Protein excess
Increased risk of cardiovascular heart disease because cholesterol
and saturated fats are found in animal proteins
Obesity as protein rich foods are high in fat
Kidney problems as by-products of proteins metabolize are excreted
via kidneys
Definitions
Deamination: breaking down of amino acids (where excess
protein is used for energy and left-over amino acids are bought to
liver)
High biological value (measure of quality of protein expressed in
a percentage and is decided by number of essential amino acids a
protein contains in proportion to how much you need): maintain
body tissue to maintain normal growth and low is the opposite
Carbohydrates (protein savers)
Classified according to number of sugars they contain (1g = 17kg)
Building blocks are simple sugars (monosaccharides)
Classifications
Monosaccharides: these are the simplest compounds (e.g., glucose
and galactose)
, Disaccharides: are two monosaccharides joined together (e.g.,
sucrose = glucose + fructose / maltose = glucose + glucose /
lactose = glucose + galactose)
Polysaccharides: large complex and are chains of monosaccharides
(e.g., starch or fiber)
Composition
Carbon
Hydrogen
oxygen
Monosaccharides
Simple compound
One sugar
Glucose (blood), fructose (fruit) and galactose (dairy)
Disaccharides
When two monosaccharides join: loose a water molecule
Sucrose (glucose + fructose), maltose (glucose +glucose) and
lactose (glucose + galactose)
Polysaccharides
Many monosaccharides: loses water molecule at each connection
Dextrin (goes brown when cooked) , cellulose (soluble breaks down
and turns to gel and non-soluble passes out body), pectin (turns into
gel like substance to help digest), starch, glycogen (stored in liver),
fiber
Starches and sugars in carbohydrates
Functions
Carbs are broken down into glucose in digestive system Blood then
carries glucose to cells to provide main source of energy
If there are enough carbs in a diet they are used for energy, saving
the protein for growth and building tissue
helps us to feel full and for longer
sources
Starch: mainly in plant-based food (bread, maize meal, oats etc.)
Sugar: cooldrinks, cake, chocolate and cakes
Starch deficiency
Can lead to lack of energy
Starch and sugar excess
Nutrients
The building blocks of whole foods that have specific functions in the
body (1g = 17kj)
Energy, growth, maintenance and repairs
Micronutrients: needed in smaller quantities (vitamins and minerals)
Macronutrients: in large quantities (protein, carbs, lipids, water)
Macronutrients
Protein
Consist of chains of amino acids that form peptides and peptides
form proteins.
21 types of amino acids
Made up form atoms
Carbon
Hydrogen
Oxygen
Nitrogen (for growth and is only nutrient that contains it)
Sometimes: phosphorus, Sulphur and iron
Peptide bonds
AA: joined together into long chains = proteins
21 AA: from many different proteins
When amino acids link water molecule is taken away (condensation)
Reverse condensation: hydrolysis where water is added to protein
chains (during digestion)
2 AA: dipeptide and many AA: polypeptide
Essential amino acids
Cannot be produced by body and provided by food
8 essentials for adults and 10 for babies
Non-essential
Can be produced by body through rearrangements of elements
Complete proteins Incomplete proteins
Has essential amino acids Lack essential amino acids
High biological value (eggs, milk, Low biological value (rice, wheat
,meat, soya and fish) and maize)
Animal origins (soya beans is only Some foods of plant
1)
Functions
Forms all part of body cells, tissues, blood, enzymes, antibodies,
nails, skin, hair and some hormones
Growth repair and maintenance of body tissue
Maintain fluid balance in body
Supply energy if there is a shortage of carbs and fats (1g = 17kj)
Animal sourced protein Plant source protein
Meat / fish Legumes (beans, lentils etc.)
Poultry body tissues Seeds and nuts
Eggs and milk and milk products Cereal, veg and fruit (small
amount)
Protein deficiencies
Can stunt growth
Can cause oedema (imbalance of fluid)
Protein excess
Increased risk of cardiovascular heart disease because cholesterol
and saturated fats are found in animal proteins
Obesity as protein rich foods are high in fat
Kidney problems as by-products of proteins metabolize are excreted
via kidneys
Definitions
Deamination: breaking down of amino acids (where excess
protein is used for energy and left-over amino acids are bought to
liver)
High biological value (measure of quality of protein expressed in
a percentage and is decided by number of essential amino acids a
protein contains in proportion to how much you need): maintain
body tissue to maintain normal growth and low is the opposite
Carbohydrates (protein savers)
Classified according to number of sugars they contain (1g = 17kg)
Building blocks are simple sugars (monosaccharides)
Classifications
Monosaccharides: these are the simplest compounds (e.g., glucose
and galactose)
, Disaccharides: are two monosaccharides joined together (e.g.,
sucrose = glucose + fructose / maltose = glucose + glucose /
lactose = glucose + galactose)
Polysaccharides: large complex and are chains of monosaccharides
(e.g., starch or fiber)
Composition
Carbon
Hydrogen
oxygen
Monosaccharides
Simple compound
One sugar
Glucose (blood), fructose (fruit) and galactose (dairy)
Disaccharides
When two monosaccharides join: loose a water molecule
Sucrose (glucose + fructose), maltose (glucose +glucose) and
lactose (glucose + galactose)
Polysaccharides
Many monosaccharides: loses water molecule at each connection
Dextrin (goes brown when cooked) , cellulose (soluble breaks down
and turns to gel and non-soluble passes out body), pectin (turns into
gel like substance to help digest), starch, glycogen (stored in liver),
fiber
Starches and sugars in carbohydrates
Functions
Carbs are broken down into glucose in digestive system Blood then
carries glucose to cells to provide main source of energy
If there are enough carbs in a diet they are used for energy, saving
the protein for growth and building tissue
helps us to feel full and for longer
sources
Starch: mainly in plant-based food (bread, maize meal, oats etc.)
Sugar: cooldrinks, cake, chocolate and cakes
Starch deficiency
Can lead to lack of energy
Starch and sugar excess
