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"  Protein is the building block of all life and is essential for the growth of cells and tissue repair. All proteins are made up of different combinations of 20 compounds called amino acids.  Depending on which amino acids link together, protein molecules form enzymes, hormones, muscles, organs and many other tissues in the body. There are two types of amino acids:    non-essential amino acids can be made by the body  essential amino acids cannot be made by the body and must be got from food. There are eight essential amino acids for adults and a further seven that children need.  Types of protein Animal protein  Animal proteins contain all the essential amino acids. This type of protein is found in:  meat poultry fish eggs dairy products.   Oily fish (salmon, sardines, trout, tuna) is a good source of protein. It has the added advantage of being high in types of fatty acid that provide protection against heart attack and to some extent stroke. Oily fish contain up to eight times as much omega-3 and omega-6 fatty acids as lean fish (cod, haddock, skate). Plant protein  Plant protein contains many amino acids, but no single source contains all of the essential amino acids. This type of protein is found in:  legumes (peas, green beans) cereals beans pulses grains nuts seeds soya products vegetable protein foods, such as Quorn or veggie mince.  You need to combine different plant proteins to make up the complete range of amino acids needed by your body.  In practice, this is achieved without any special effort, for example by eating baked beans with bread (toast) or using milk on cereal. Plant versus animal proteins  In terms of healthy eating, you should aim to eat a diet with a higher proportion of plant proteins than animal ones.  Processed foods  Sausages and burgers may be the obvious culprits. But so are smoked foods, which are also high in salt. Try to keep foods, such as smoked bacon and salmon, to occasional treats.   Many animal proteins are high in saturated fat or cooked with a lot of fat (oil, lard, dripping). Studies have linked eating a lot of red and processed meat to an increased risk of bowel and stomach cancer. Cooking meat, poultry and fish at high temperatures creates chemicals called heterocyclic amines (HAs) and polycyclic aromatic hydrocarbons (PAHs). It&amp;#039;s thought HAs and PAHs may increase our risk of cancer, but more research is needed. PAHs are also found in the exhaust fumes and tobacco smoke. Plant-based proteins are low in fat and high in fibre, vitamins and minerals. Plant proteins contain phytochemicals that contribute towards health and disease prevention. For example, isoflavones found in soya beans have antioxidant properties, thought to be important in the prevention of cancer and menopausal symptoms.  How much do I need? Energy and protein   1g carbohydrate: 3.75 calories. 1g protein: 4 calories. 1g fat: 9 calories. 1g alcohol: 7 calories.   Current advice says protein only has to make up 10 to 15 per cent of your daily diet to meet your body&amp;#039;s needs. That&amp;#039;s around 55g for men and 45g for women. Most of us eat more than this, and the British Nutrition Foundation puts the average adult intake at 88g for men and 64g for women.   Around two thirds of the protein we eat is from animal sources. We get a quarter of our protein from cereal products (wheat, bread, oats). Nuts and pulses make up most of the final twelfth.  How much protein do foods contain? Below are some examples of foods, so you can compare protein content.  You can also check nutrition labels to find out how much protein something contains.   One skinless chicken breast (130g): 41g protein. One small fillet steak (200g): 52g protein.  One beef burger or pork sausage: 8g protein. One portion of poached skinless cod fillet (150g): 32g protein. Half a can of tuna: 19g protein. One portion of cheese (50g): 12g protein. One medium egg: 6g protein. 150ml glass of milk: 5g protein. One tablespoon of boiled red lentils (40g): 3g protein. One portion of tofu (125g): 15g protein. One slice medium wholemeal bread: 4g protein. One slice medium white bread: 3g protein.   Tips for healthy living  Include oily fish in your diet at least twice a week. Try using soya products, such as veggie mince and tofu. They will take up the flavour of the dish if you add them to stews and sauces. Snack on seeds and unsalted nuts. Try sunflower, pumpkin or sesame seeds and brazils, cashews, walnuts, hazelnuts or almonds. Look at using pulses as an alternative source of protein. They include chickpeas, a wide range of lentils, split peas and a vast range of beans from the black-eyed to the broad, butter and kidney. Have one vegetarian meal each week.  You don&amp;#039;t need to banish meat from your diet altogether.    Use lean cuts of meat and poultry. Trim off any fat, eg the skin on chicken breasts and the rind on bacon. Choose smaller portions. Reduce the frequency of meat-based meals. Pay particular attention to how you cook meat.  Temperature is the most important factor in the production of heterocyclic amines (HAs).   Frying, chargrilling, and barbequing produce the largest amounts of HAs when the cooking temperature is increased from 200\u00B0C to 250\u00B0C. Oven roasting and baking use lower temperatures and so produce lower levels of HAs. Stewing, boiling and poaching all use temperatures below 100\u00B0C and so produce very few HAs. Avoid gravy made from dripping because it contains substantial amounts of HAs. Microwaving meat for two minutes before cooking reduces the HA content by about 90 per cent. Cooking meat for a long time (ie well done or very well done) produces more of these chemicals. Protein from milk, eggs, tofu and organ meats, such as liver, have very little or no HA content, even when cooked.  Other articles in this series  General lifestyle management  Body weight Fats Carbohydrates Fibre Soya Water Caffeine  Smoking and nutrition Alcohol metabolism Exercise   Based on a text by Dr Dan Rutherford, GP  Last updated 02.02.2014 "^^<http://www.w3.org/2001/XMLSchema#string>
<http://www.netdoctor.co.uk/healthy-eating/a10832/protein/>