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 Protein alternatives 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 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 Function Sources Deficiency Excess DRV 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