Definition Protein is a nutrient. Proteins are like long necklaces made up of beads called amino acids. Our bodies can make most of the 20 different types of amino acids. For adults, eight have to be provided by the foods we eat. The amino acids that we can't make are called essential or indispensable. The ones that don't have to be provided by the diet are called non-essential or dispensable amino acids. Why we need protein Protein is the building material for muscles, bones, skin, organs and other tissues in the body. If these tissues are injured then protein is needed to repair them. Protein is the main component of enzymes, which are used to digest the foods that we eat. Antibodies are also made from protein. These help to keep you well by fighting against bugs and infections. Protein is the main nutrient that keeps our hair, skin and nails strong and healthy. Proteins act as buses to carry nutrients and compounds to areas in the body where they are needed; for example, protein ferries haemoglobin around in the blood. Haemoglobin carries oxygen to every part of the body. Lastly, protein can provide fuel for the body. There are four calories in every gram of protein. Where to find it Meat, chicken, fish, seafood, eggs, milk, cheese, lentils, tofu and beans are all good sources of protein. Proteins from animal foods are called complete because they contain all of the essential amino acids we need. Vegetable proteins are called incomplete because they're missing at least one of the essential amino acids. If you are a vegetarian, you can still get all the amino acids you need from different vegetables and grains. For example, lentils don't contain all the essential amino acids but the rest can be found in rice. Lentils and rice complement each other in the same way as bread and peanut butter, bread and cheese or beans and baked potatoes. If we eat too much Some protein-rich foods like red meat contain a lot of unhealthy fats so eating too much of them can put us at risk of heart disease. Protein contains a lot of nitrogen, a substance which is harmful to the body and has to be eliminated by the kidneys. Excess protein can't be stored in the body - it has to be converted into glucose, and is then either used as fuel or stored as fat. How much we need You require only about 1g protein a day for every kilogram that you weigh. You can work out how much protein you've eaten by looking at food labels. If you are eating a balanced diet, you won't need to work out the exact number. Just remember that you need 2-3 servings of lean protein foods a day. If you are a vegetarian, make sure you eat a variety of foods with different types of vegetable proteins. One portion = 85g of beef/lamb/pork/fish/chicken 1 large egg 1/2 cup beans or lentils 2 tablespoons seeds 2 tablespoons peanut butter 2 tablespoons nuts 113g tofu Quiz Test your protein IQ 1. Which of the following foods contain the least protein? a 2 large eggs b 1/2 cup tofu c 1 cup skimmed milk 2. Which of the following contains the most protein? a 85g cooked salmon b 85g roast beef c 85g roast chicken 3. Can you guess the size of an 85g serving of meat? a a deck of playing cards b a baseball c a clenched fist 4. Which of the following dim sum dishes contains the most protein? a 100g steamed char siu bao (pork bun) b 100g har gau (prawn dumpling) c 100g steamed siu mai (pork dumpling) Answers: 1 c Milk contains the least protein - 8.7g, followed by a, eggs - 12.6g, and then b, tofu - 19.9g. 2 c Chicken contains the most protein - 26.7g, followed by b, roast beef - 24.9g, then a, salmon - 21.7g 3 a a deck of cards 4 c siu mai contains the most protein - 9g, followed by a, char siu bau - 7.3g, then b, har gau - 6.7g
