Proteins are nutrients the body needs to function properly, to grow and repair cells; it is classed as a macronutrient and each gram of protein counts as 4 calories.
Proteins are found in a wide range of foods and it’s important that you get enough proteins in your diet every day. How much protein you need from your diet varies depending on your weight, gender, age and level of physical activity.
Proteins are made up of building blocks called “amino acids”. There are about 20 different amino acids that link together in different combinations. Your body uses them to make new proteins, such as muscles and bones, and other compounds such as enzymes and hormones; the body can also use them as an energy source. Amino acids can be used by the body to repair tissues and form hormones, enzymes and neurotransmitters, among performing other functions.
Some amino acids can almost always be made within our bodies (except in certain rare diseases or disorders); there are 11 of these amino acids that are known as non-essential amino acids. There are 9 amino acids that our body cannot make, and they are known as essential amino acids. We need to include enough of these essential amino acids in our diet so that the body can function properly.
Those essential amino acids are:
1. Isoleucine
2. Leucine
3. Lysine
4. Methionine
5. Phenylalanine
6. Threonine
7. Tryptophane
8. Valine
9. Histidine.
Animal products such as chicken, beef, fish, eggs and dairy products have all of the essential amino acids in large quantities and are known as ‘complete’ protein or high-quality protein.
Soya products, quinoa, buckwheat, hemp, chia and amaranth seeds (a leafy green consumed in Asia and the Mediterranean) also have all of the essential amino acids and can be considered healthiest and complete proteins.
Other plant proteins such as beans, lentils, nuts and whole grains usually lack one or more of the essential amino acids and are considered ‘incomplete’ proteins. However, a variety of these in a meal will provide a package full of amino acids needed.
People following a strict vegetarian or vegan diet need to choose a variety of protein sources from a combination of plant foods every day to make sure they get an adequate mix of essential amino acids; Such diet should include soy and soy products such as soybeans, tofu and tempeh to maximise on the essential amino acids needs. If you follow a strict vegetarian or vegan diet, as long as you eat a wide variety of plant based foods, you should be able to get all the protein you need. For example, a meal containing cereals and legumes, such as baked beans on toast with a side/smoothie of kale or spinach with soy milk as an example, should provide all the essential amino acids found in a typical meat dish. Also consider adding seeds in your meals to incorporate a variety of amino acids (pumpkin seeds, hemp seeds, chia seeds, etc).
The Reference Nutrient Intake (RNI) for protein for adults is 0.75g protein per kg body weight per day; this equates to 56g/day and 45g/day for men and women of average body weights (75 and 60kg respectively). RNIs have also been set for children from birth to 10 years and for pregnancy and lactation. Average intakes of protein in the UK are above this recommendation in all age groups.
Protein foods
Some food sources of dietary protein include:
● lean meats – beef, lamb, veal, pork.
● poultry – chicken, turkey, duck, emu, goose.
● fish and seafood – fish, prawns, crab, lobster, mussels, oysters, scallops, clams
● eggs
● dairy products – milk, yoghurt (especially Greek yoghurt), cheese (especially cottage cheese)
● nuts (including nut pastes) and seeds – almonds, pine nuts, walnuts, macadamias, hazelnuts, cashews, pumpkin seeds, sesame seeds, sunflower seeds
● legumes and beans – all beans, lentils, chickpeas, split peas, tofu and tempeh.
Moreover, recent nutritional studies on proteins are clear: the proteins we get from plants are the best, high quality proteins the body needs. That’s because the more plant based proteins you incorporate in your diet, the more likely you are to have a longer, happier healthier life with reduced incident of cardiovascular diseases, cancer, fatty liver disease. And there is something more about this low saturated fats foods, fibre packed, cholesterol free, high quality proteins that our bodies just love. A combination of plant based proteins in the daily diet will provide all the amino acids the body needs.
Getting more protein into your day, naturally.
If you’re looking for ways to get more protein into your diet, here are some suggestions:
● Try a peanut butter sandwich. Remember to use natural peanut butter (or any other nut paste) with no added salt, sugar or other fillers.
● Low-fat cottage or ricotta cheese is high in protein and can go in your scrambled eggs, casserole, mashed potato or pasta dish. It can also be spread it on your toast in the morning.
● Nuts and seeds are fantastic in salads, with vegetables and served on top of curries. Try toasting some pine nuts, flaked almonds or flaxseeds and putting them in your green salad.
● Beans are great in soups, casseroles, and pasta sauces. Try tipping a drained can of cannellini beans into your favourite vegetable soup recipe or casserole.
● A plate of hummus and freshly cut vegetable sticks as a snack or hummus spread on your sandwich will give you easy extra protein at lunchtime.
● Greek yoghurt is a protein rich food that you can use throughout the day. Add some on your favourite breakfast cereal, put a spoonful on top of a bowl of pumpkin soup or serve it as dessert with some fresh fruit.
● Eggs are a versatile and easy option that can be enjoyed on their own or mixed in a variety of dishes.
Deficiencies
Deficiencies of dietary protein are usually classified into marasmus, a general wasting due to a deficiency of both protein and energy, and kwashiorkor, characterized by a distinctive edema and a deficiency of both protein quantity and quality. Less severe deficiencies, due to low intake or an imbalance in indispensable amino acids intake, may result in reduced growth in children or a loss of lean body mass in adults.
Please consider consulting a nutritionist, dietitian or general practitioner if you are worried about your nutritional status.
References
https://www.sciencedirect.com/topics/nursing-and-health-professions/protein
https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/protein/
https://www.livescience.com/53044-protein.html
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3905294/
https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.118.035225