GCSE WJEC Food Preparation and Nutrition - Food, nutrition and health

Macronutrient

A nutrient that the human body needs in large amounts

Protein

A macronutrient made from chains of amino acids

Uses of protein

- Growth E.g. nails, hair and muscle mass
- Repair of muscles, tissues and organs
- Maintenance E.g. enzymes and antibodies

11

Number of non-essential amino acids. (ones that the body can make)

9

Number of essential amino acids. (ones that the body can't make, so must be eaten)

High biological value (HBV)

Sources of protein that contain all of the essential amino acids

Sources of HBV

- Meat / poultry
- Fish
- Dairy
- Soya / quinoa

Low biological value (LBV)

Sources of proteins that do not contain all the essential amino acids

Sources of LBV

- Peas
- Nuts
- Pulses
- Spinach

Protein complementation

Combining different sources of LBV proteins to provide all the essential amino acids. E.g. hummus and pita individually do not provide all the essential amino acids, but together they do

Dietary reference values (DRV)

Estimates for the amount of nutrients people should have in their diet

DRV of protein

55g for men
45g for women

Varies of protein requirement

- Children need more for growth
- Physically active people need more for growth and repair
- Pregnant women need 6g more for foetal development
- Lactating people need more for baby development

Protein excess

Pressure and strain on kidneys and liver (could lead to organ failure)

Protein deficiency

- Growth reduction
- Weakened immune system
- Weakened digestive system (nutrients aren't taken up)
- Oedema (fluid build up leading to swelling)
- Kwashiorkor (swollen organs, loss of muscle mass)

Vegetarian

Someone who doesn't eat products sourced from killing animals (meat, gelatine, etc.)

Alternative sources of protein

- Soya
- Mycoprotein
- TVP
- Tofu

Soya

- Plant based HBV source
- Must be cooked to remove toxicity

Mycoprotein

- Made from mushroom fungus and egg white / potato starch
- Replacement for poultry
- Comes in chunks, mince and fillets

TVP

- Textured vegetable protein. Made from soya flour (ground soya beans)
- Baked dough with meat-like texture
- Replacement for sausages, burgers and ready meals

Tofu

- Made from curdling soya milk
- Varying texture depending the amount of liquid it contains
- Used in desserts, dips, stir fries

Properties of alternative proteins

- Not much flavour
- Good at absorbing flavour (prepare with sauces, marinades, etc.)

Lipid

A macronutrient made from chains of fatty acids. Either fats (solid) or oils (liquid)

Uses of lipid

- Concentrated source of energy (twice as much as protein and carbs)
- Source of fat soluble vitamins (A and D)
- Source of essential fatty acids (omega 3 and 6)
- Forms an insulating layer to keep us warm
- Forms a protective layer around organs and bones
- Makes cholesterol (substance in cell membranes)

Triglyceride

A lipid made of 3 fatty acid molecules and one glycerol molecule

Glycerol

A three-carbon alcohol to which fatty acids are covalently bonded to make fats and oils.

Fatty acids

Chains of carbon and hydrogen that forms the monomer of lipids

Saturated fatty acids

Fatty acids that contain the maximum amount of hydrogen atoms as possible (only C-C single bonds)

Unsaturated fatty acids

Fatty acids that do not contain the maximum amount of hydrogen atoms (contain C=C double bonds)

Saturated lipid

- Solid at room temperature (fat)
- Generally come from animal sources, but also come from some plant sources
- Excess consumption can lead to cardiovascular disease

Unsaturated lipid

- Liquid at room temperature (oil)
- Generally come from plant sources)
- Lowers blood cholesterol
- Can be either monounsaturated or polyunsaturated

Monounsaturated lipid

- Contain one C=C double bond
- Found in olive oil, nuts and avocado

Polyunsaturated lipid

- Contain multiple C=C double bond
- Found in sesame oil, soybean oil, seeds and oily oil

Essential fatty acids

The fatty acids that the body can't produce (omega-3 and omega-6)

Omega-3

- Found in oily fish and seeds
- Improve brain function and reduces risk of heart disease

Omega-6

- Found in chickens, nuts, vegetable oils
- Lowers blood cholesterol and reduces inflammation

35%

Proportion of daily food energy that should come from fat

DRV of lipid

70g
20g of which coming from saturates

Lipid excess

- Weight gain, especially build up around organs which leads to strain
- Obesity
- Increased cholesterol levels, restricting blood flow and high blood pressure

Lipid deficiency

- Vitamin deficiency
- Weight loss
- Less insulation (colder)
- Less protection

Carbohydrate

A macronutrient made chains of carbon based molecules. Can be simple or complex

Intrinsic sugar

Sugar that occurs naturally in food. E.g. fruit and vegetables

Extrinsic sugar

Sugar added to food by manufacturers. E.g. cakes and sweets

Added Sugar

Provides energy but nothing else so is sometimes referred to as 'empty calories'

Starch

- How plants store glucose
- Found in potatoes, bread, pasta, rice and cereals
- These foods also contain other nutrients including B vitamins, iron, calcium and fibre

Digesting carbohydrates

- Sugar and starch is broken down into glucose, which is absorbed and used for energy (respiration)

Monosaccharides

- A simple sugar
- The most basic sugar molecules. E.g. glucose, fructose

Disaccharides

- A simple sugar
- Two monosaccharides joined together. E.g. sucrose is made of glucose and fructose

Effect of simple sugars

Rapidly digested making blood sugar levels rise quickly and short burst of energy. Often come from high GI foods

Polysaccharides

- A complex sugar
- A polymer of lots of monosaccharides. E.g. starch is a chain of glucose molecules

Effect of complex sugars

Digested slowly, causing a slow steady burst of energy. Often come from low GI levels

Glycaemic index

The scale of how quickly carbohydrates affect blood sugar levels

High GI foods

- Mainly simple sugars
- Digested quickly and cause a rapid rise in sugar levels
- Include watermelon, white bread / pasta / rice

Low GI foods

- Mainly complex sugars
- Digested slowly causing a gradual rise in blood sugar levels
- Include peaches, brown bread / pasta / rice, porridge

50%

Proportion of daily food energy that should come from carbohydrates

5%

Proportion of daily food energy that should come from sugars

Of which sugars

The part of Uk food labelling that helps people separate their sugar intake fro their carb intake

Carbohydrate excess

- Converted into fat (obesity)
- Dental caries (decay)
- Fluctuating blood sugar levels, this can lead to Type 2 diabetes

Carbohydrate deficiency

- Reduced blood sugar levels, this can lead to hunger, dizziness and tiredness
- Fat is used for energy instead
- Protein is used for energy, which leads to loss of muscle mass

Micronutrient

Essential nutrients needed by the body in small or trace amounts

Vitamins

Organic compounds needed by the body in small amounts but are still essential

Fat soluble vitamins

Organic compounds that are soluble in fat and are therefore found in fatty foods. Vitamins A, D, E, K

Uses of vitamin A

- Eyesight
- Healthy immune system
- Healthy skin

Sources of vitamin A

- Retinol, which is found in liver, butter, oily fish and egg
- Carotene, which is found in margarine and yellow fruit and veg

DRV of vitamin A

0.7 mg for men
0.6 mg for women

Vitamin A excess

- Weaken bones
- Harm to foetuses
- Fatal in extreme circumstances

Vitamin A deficiency

- Night blindness
- Weak immune system
- Stunted growth

Uses of Vitamin D

- Absorb various minerals
- Teeth and bone development

Sources of vitamin D

- Oily fish
- Egg yolks
- Produced by the body when exposed to sunlight

DRV of vitamin D

0.01 mg

Vitamin D excess

Hypercalcemia - kidney damage
Nausea
Constipation

Vitamin D deficiency

Bone diseases such as:
- Osteomalacia (bone become soft)
- Rickets and osteoporosis (bones become brittle)

Uses of thiamin (B1)

- Improved nervous system
- Energy release from food

Sources of thiamin (B1)

- Pasta
- Eggs
- Liver
- Peas

Thiamin (B1) deficiency

- Tiredness
- Weak muscles
- Beriberi (disease that affects the heart, vessels and nervous system)

Uses of riboflavin (B2)

- Energy release from food
- Tissue repair

Sources of riboflavin (B2)

- Dairy
- Eggs
- Leafy greens

Riboflavin (B2) deficiency

- Dry skin
- Sore throat
- Sores around the mouth

Uses of niacin (B3)

- Healthy nervous system
- Energy release from food
- Healthy skin

Sources of niacin (B3)

- Wheat
- Nuts
- Meat
- Fish

Niacin (B3) deficiency

Pellagra (disease causing fatigue, depression and memory loss)

Uses of folic acid (B9)

- Growth of babies
- Production of red blood cells
- Essential to have high levels at conception to avoid birth defects

Sources of folic acid (B9)

- Liver
- Peas
- Leafy greens

Folic acid (B9) deficiency

- Anaemia
- Weak muscles
- Mouth sores
- Spina Bifida in newborns

Uses of Cobalamin (B12)

- Production of red blood cells
- Healthy nervous system

Uses of ascorbic acid (vitamin C)

- Protection from infection and allergies
- Healthy blood vessels
- Healing wounds
- Absorption of iron

Sources of ascorbic acid (vitamin C)

- Citrus
- Strawberries
- Green veg
- Potatoes

Excess ascorbic acid (vitamin C)

- Stomach pain
- Diarrhoea

Ascorbic acid (vitamin C) deficiency

- Anaemia
- Scurvy (tiredness and bleeding gums)
- Increased risk of cancer

Preparation of fruit and vegetables

- Prepare the just before you need them to retain vitamin C
- Steam or microwave them
- Don't chop into small pieces as it increases surface area
- Peel thinly or not at all as most nutrients are just below the skin

Minerals

Chemical elements, usually metals, that are needed by the body in small amounts, but are still essential

Uses of calcium

- Strong teeth and bones
- Healthy nerves and muscles
- Blood clotting

Sources of calcium

- Dairy
- Hard water
- Green leafy veg
- Tofu

Calcium excess

- Kidney stones
- Hypercalcemia
- Kidney damage

Calcium deficiency

- Rickets
- Osteoporosis
- Slowed blood clotting

Uses of iron

- Forms haemoglobin
- Forming proteins

Sources of iron

- Meat
- Dark green vegetables

Iron excess

- Stomach pains
- Nausea
- Constipation
- Death

Iron deficiency

- Anaemia
- Heat palpations
- Headaches

Uses of potassium

- Cardiovascular health
- Controlling fluid balance
- Works with sodium to control muscles and nerves