Protein – why it’s so important for us

We’re always told how important protein is to our diet and that we need to consume enough of it. Any Google search for protein will return a million and one results for protein sources, whether is’s via food stuffs or supplements and powders, but very rarely will you find anything that gives you a definitive answer to what protein is and what is does. Sure we all know the standard ‘proteins are the body’s building blocks’ and that ‘your body needs protein to develop muscles’ but ask most people to explain either of these and they’ll probably not be able to do so.

What is protein?

The Oxford dictionary definition of protein is ‘a class of nitrogenous organic compounds which have large molecules composed of one or more long chains of amino acids and are an essential part of all living organisms, especially as structural components of the body tissues such as muscle, hair, etc., and as enzymes and antibodies‘ which doesn’t really tell you too much apart from the fact it’s important and contains amino acids.

To really understand what protein is you need to first understand what amino acids are. Containing carbon, hydrogen, oxygen and nitrogen, amino acids are the key elements of the proteins and are the second largest component of human muscles after muscular tissue. Today there are around 500 naturally occurring amino acids (20 of which are needed by the human body) that have been discovered. There are of course a number of synthetic amino acids too. Our body’s aren’t able to store animo acids in the same way they can with carbohydrates and fats which is why we need to eat protein every day.

There are two main types of protein, complete protein and incomplete protein. Complete proteins contain all of the nine amino acids the body needs, these general come from animal sources such as meat, fish, poultry and dairy. Incomplete proteins on the other hand will have at least one of the nine amino acids we need missing and as a rule are from fruit, vegetable, grain and nut sources.

How does protein work?

When we consume any amount of protein our body starts to to break it down into it’s various components and then ships that off around the body to carry out various functions. The important constituent of protein is amino acid, it’s these that your body needs for its daily survival. That may sound dramatic to call it a ‘daily survival’ but if you read on you’ll see just how important these really are. There isn’t a single element of the human body that doesn’t need animo acids in one way or another. They are even play an important rule in your mood as well as how much sleep you get.

Why do we need protein?

Our bodies can’t produce (or synthesise) certain amino acids itself so we have to get these animo acids (known as essential amino acids) purely from our diets. The other amino acids, known as non essential are either produced from essential amino acids or from the normal breakdown of proteins. It’s because of the benefits and functions of all of these essential and non essential amino acids that protein is so important to our daily lives.

Essential amino acids:
  • Isoleucine – This is particularly important for athletes and body builders as it can increase endurance and help heal muscles. It can be found in things like chicken, eggs, soy beans and cashew nuts.
  • Leucine – This can help reduce the bodies blood sugar levels and increase the production of muscle proteins and has been found to slow the degradation of muscle tissue. Leucine can be found in protein rich foods such as beef, fish, eggs and chicken.
  • Lysine – Is largely used in the absorption of calcium and is also used to help produce hormones, enzymes and antibodies. Lysine is found in many dairy products and pulses.
  • Methionine – Being a sulphur containing proteinogenic amino acid Methionine is utilised in the cleaning of the liver and can be found in meat, fish and diary products as well as in lower amounts in whole grains.
  • Phenylalanine – Helps to promote mental alertness and memory whilst also increasing your mood and suppressing your appetite. Phenylalanine also helps in the formation of adrenaline. Recent studies have also indicated that it might help treat chronic pain as well as help to alleviate some of the symptoms of Parkinson’s disease – although it’s early days in this research. It can be found in many foods but has also been found in aspartame which is a artificial sweetener.
  • Threonine – Used by various systems in the body such as the nervous, cardiovascular and immune systems. It also helps to produce collagen and muscle tissue as well as build strong bones and teeth. Threonine can be found in most foods but in higher concentration in meats, fish, dairy and eggs.
  • Tryptophan – This helps to regulate a number of functions such as sleep, pain perception, temperature and even blood pressure and as such has been used in the treatment of insomnia and anxiety and depression to name a few. Tryptophan can be found in many seeds and nuts as well as in tofu, cheese, pulses and meats especially red meats.
  • Valine – Provides the muscles with extra glucose which in turn helps to prevent their breakdown. It can also provide energy during exercise. This is largely found in kidney beans and leafy vegetables as well as in poultry and dairy products.
Semi essential animo acids:
  • Histidine – This is classed as semi-essential because the body doesn’t always need it to function. Adults are able to produce enough naturally although children aren’t always able to. It’s a precursor of histamine which is released by the body in the event of an allergic reaction. It can be found in most meats as well as dairy, pulses and eggs.
Non-essential amino acids:
  • Alanine – Mainly known for improving the immune system and increasing the amount of energy provided to the brain. It essentially converts glucose into energy and removes toxins from your liver.
  • Arginine – Plays an important role in the body’s immune system as well as helping the body to heal from wounds. Its effects are especially beneficial during colds and migraines.
  • Asparagine – The nervous system needs Asparagine to help it maintain a balance but it’s also utilised by the body to protect liver function. This has resulted in it being known for its ability to reduce fatigue and improving stamina.
  • Aspartic acid – A vital component in the use of stamina as well as for brain and neurological health. It was recently discovered to be important in DNA as well as in producing immunoglobulin which is an antibody. It has also been used to treat depression.
  • Cysteine – Responsible for the production of white blood cell activity it is also needed by the skin and can help you recover quicker after surgery. The human body can produce this amino acid but it is also present in pork, chicken, eggs, milk, cottage cheese, garlic, onions and granola.
  • Glutamic acid – Helping to increase neurotransmitters fire neutrons in the central nervous system, especially in the brain and spinal cord. Despite being essential for the proper functioning of cells it’s considered as non essential because the body is able to produce it itself.
  • Glutamine – Sometimes called L-Glutamine it’s most commonly known for it’s involvement in the metabolic process. It’s converted to glucose and helps to maintain a normal blood glucose level.
  • Glycine – Supporting the digestive system it is also vital for the development of skeletal muscles, tissues and in the synthesis of nucleic acids which are essential in all forms of life.
  • Proline – Crucial for the proper functioning of joints and tendons, proline also helps to maintain a strong and healthy heart. Like many other amino acids it can also help in provide energy to the body.
  • Serine – Along with glycine, serine is important in for the proper functioning of the digestive system. It also plays an important role in your general health, both mental and physical.
  • Tyrosine – Increasing the dopamine and noradrenalin levels it is very helpful in relieving pain. Used by neurotransmitters it’s closely linked to the brains health.

Protein sources:

Protein can be obtained from any number of sources but they’re not all equal. We mentioned previously protein can be either complete or incomplete but different sources have different qualities and quantities of protein too. You can read about the protein sources of supplements in our recent ‘Definitive guide to protein sources‘, but for protein obtained through food there is still a variety in the quality of protein. For example fish (particularly oil fish) is very high in a fatty acid know as omega-3 and, unlike red meats, is lower in other fats. Beans on the other hand have the highest concentration of protein than any other vegetable, with things like whole grains trailing with only around 3 grams of protein per slice of whole wheat bread.

Approximate protein content per 100g:
  • Meat (without skin) – This can range from 29g to 32g
  • Fish – Depending on the fish that can be anything from 20g to 24g
  • Seafood – While prawns are high in protein with around 23g seafood can contain as little as 10g
  • Dairy – Dairy ishas a wide protein gamut so can range from as little 3g to over 32g
  • Nuts – Nuts are a very good source of protein and can be anywhere between 14g and 21g
  • Grains – Containing many different food stuffs such as easy cook rice and wheat grain, grains can be anywhere between 2g and 13g
  • Pulses – Tends to be round 7g or 8g
  • Beans (including soya bean) – These can range from 5g to over 8g

What happens if you have too little protein in your diet?

If you regularly don’t eat enough protein (approximately 50 grams a day) it can have a detrimental effect on your body and physique. Protein is so important to your body that if it doesn’t get enough from your diet, whether it be via food or supplements it will, in time, turn on itself and start breaking down your muscles to use the protein stored within them. If you don’t get enough protein you’ll also find you start to put on weight. While this isn’t as a direct result of not having enough protein it’s because you will start to crave sugars because your body is trying to make up the deficit another way. 

Can you have too much protein?

We now know how important protein is for us but that doesn’t mean we need to eat as much protein as we possibly can. Protein is like everything else and should be consumed in moderation. Yes it’s more important that any other nutrient you eat but too much of it can be extremely bad for you. The effects of too much protein can range from problems with you kidneys because they can’t process the increased amount of nitrogen, this can make you more thirsty in mild cases but in extreme cases, for somebody on a long term high protein diet, it can result in kidney damage. Being a factor in tissue growth too much protein can of course lead to weight gain but not just in bulk but in excess fat too as your body can only create so much muscle at any one time.


In summary proteins are the fuel that helps our body to survive. It’s not just for building muscle but for any tissue repair it needs to do. If you cut yourself it’s the amino acids in protein that will help the skin to grown again. During periods of fasting you body will begin autophagy which is the process by were old cells are ‘cleaned out’ and regenerated.

The amount of protein each person needs is dependant a large number of factors such as your age, height, weight, gender etc. You can use our BMR calculator to work out how much protein you yourself need each day.

It’s important to consume enough protein everyday but sometimes that isn’t as easy as you might think with food alone. We’ve come a long way from the early days of protein shakes where there was no science behind them. These days there’s so much science and nutritional research that goes into producing protein supplements that it’s a very good and healthy way to top up your body’s protein levels.

If you’re after natural protein sources you can’t go far wrong with websites like musclefoods and for protein powders and supplements you can checkout out comparison site.