Download Macronutrients

Macronutrients
Protein
The macronutrients are:
Protein
Fats
Carbohydrate
They are required in large
amounts in the diet.
The functions of protein
Protein is needed for:
• growth of body cells and tissue
• repair and maintenance of all body tissue
• providing a secondary source of energy (the main
source of energy in your diet should be from starchy
carbohydrates).
How much protein do
different people need?
Different people need different amounts of protein:
• Men need more protein than women as they are
normally taller than women and have more muscle
tissue.
• Babies and children need a lot of protein (relative to their
size) as they are growing.
• Teenagers need more protein for their rapid growth
spurts.
What are proteins made from?
• Proteins are made from amino acids.
• There are about 20 amino acids.
• These amino acids combine in different ways to make all the
proteins in your body.
Essential and non-essential amino acids
• Some amino acids can only be obtained from food. These are
called essential amino acids.
• There are eight essential amino acids needed by adults and
children. Some extra ones are needed by children because
they are growing.
High biological value proteins
• Foods that contain all of the essential amino acids are called
high biological value (HBV).
• HBV proteins come mainly from animal proteins, for example meat, fish,
dairy produce and eggs.
• There are some exceptions to this rule – soya beans and quinoa. These
contain all of the essential amino acids.
- Soya beans have many uses. They may be used in their natural bean
form, for example in a soya bean casserole. Alternatively, soya is used to
make many products such as textured vegetable protein (TVP), tofu, soya
milk and soya desserts.
- Quinoa may be used in the same way as rice in cooking.
Low biological value proteins
• Foods that lack one or more of the essential amino acids are called low
biological value (LBV).
• LBV proteins are supplied by plant foods: beans (except soya beans), pulses,
nuts, seeds and cereals.
Protein complementation
• When LBV proteins are eaten together, the biological value will
increase. This is because the essential amino acids missing in
one LBV food can be supplied by another LBV food.
• For example, beans are lacking one essential amino acid and
bread is lacking one essential amino acid, but together these
foods supply all of the essential amino acids. Combining LBV
foods in this way is called protein complementation.
Examples of protein complementation
•
•
•
•
Beans on toast
Lentil dhal and chapattis
Rice and peas
Hummus and pitta bread
Sources of protein
High biological value sources of protein
Low biological value sources of protein
Meat
Fish
Eggs
Cheese
Yoghurt
Soya beans
Mycoprotein (e.g. Quorn™)
Quinoa
Pulses (peas, beans and lentils)
Cereals (e.g. wheat, rice, oats and
barley)
Nuts
Seeds
Protein alternatives
• Soya – Textured Vegetable Protein (TVP), Tofu, Soya milk,
Tempeh, Miso
• Mycoprotein - Quorn
• Quinoa
Dietary reference values
(DRVs) for protein
The different requirements for protein (grams per day)
Age
Males
Females
1–3 years
14.5g
4–6 years
19.7g
7–10 years
28.3g
11–14 years
42.1g
41.2g
15–18 years
55.2g
45g
19–49 years
55.5g
45g
50 years+
53.3g
46.5g
Reference: Nutrient Intakes from Department of Health
Dietary Reference Values for Food Energy and Nutrients
for the United Kingdom, HMSO, 1991
Deficiency of protein
• Protein deficiency is very rare in the developed world as
most people eat a wide range of foods.
• Kwashiorkor is a deficiency disease caused by a lack
of protein.
• Kwashiorkor can occur in children in developing
countries where there is famine or an unstable food
supply.
• Symptoms of kwashiorkor include poor growth rates,
water retention, hair loss and infections.
Eating excess protein
• Eating too much protein may be harmful to the kidneys
and liver because they have to break down the protein.
• If you don’t use the extra protein consumed for energy, it
will be stored as fat, which can lead to weight gain.
Nutrient
MACRO
Protein
Fats
Carbohydrates
MICRO
Fat-soluble
Vit A
Vit D
Vit E
Vit K
Water-soluble
Vit B1 (Thiamin)
Vit B2
(Ribovlavin)
Vit B12
Folic Acid
Vit C
Function
Sources
Deficiency
Excess
DRV