What is Protein?

Protein is one of the 3 essential macronutrients along with carbohydrates and fats and is found in every cell in the body including our hormones, immune system and enzymes.

Protein is made up of building blocks of amino acids of which there are 20. Some amino acids are non-essential, meaning the body can synthesise them, or essential meaning the body is unable to synthesise them and we must gain them from our diet.

The body uses protein to build, repair, replenish and grow all building blocks of the body. You will find them as a part of the bone matrix, in the ligaments in the form of collagen, in our tendons, skin and muscles. It is also involved in day to day cell turn over, including the skin and GI tract.

What is protein found in?

Sources of protein

Although often thought of as being a meat-based nutrient, there are plenty of excellent vegetarian sources of protein including: kidney beans, chickpeas, quinoa, almonds, sunflower seeds and alfalfa sprouts which all add up to contribute to your daily intake.

When thinking about which food source we choose for our protein, it is important to consider which other nutrients are attached to the food. For example, red meat will also come with saturated fats, fish with omega 3 and lentils with fibre. This is known and the ‘protein package’ and is important to consider in helping us ensure we are eating a balanced diet.

Protein deficiency in the west is rare, however complications from protein deficiency include: reduced muscle mass, growth disruptions and weakened heart and lung function. In the most severe cases of protein deficiency, a condition called kwashiorkor can develop, leading to fluid retention and swelling under the skin, often seen on the abdomen of small children.

What are the benefits of protein?

For this reason protein is especially important in times of development such as childhood, adolescence and pregnancy, as well as times of repair and recovery.

Amino acids form the base of many important hormones in the body. Thyroid hormones are synthesised from tyrosine and iodine, hormones for positive brain function like seratonin and melatonin are synthesised from tryptophan. Plasma membrane proteins can also form the hormone receptors, making protein essential on both sides of hormone signalling.

Protein also form an essential part of enzymes, which act as catalysts in the body to break down, rebuild or to speed up certain functions, for example digestive enzymes.

Antibodies, or immunoglobulins like IgG (intolerances) and IgE (allergies) are made up of proteins and form a part of the immune system to help identify harmful foreign substances.

Some proteins known as transport proteins, couple up with another substances and help to transport them through the body via the blood or cells. Examples of substances who rely on transport proteins include: thyroid hormones, fatty acids, vitamin A and various minerals.

In weight management, protein can help through various mechanisms. Hormonally, it increases satiety signals and reduces hunger hormones like ghrelin. It can also increase insulin sensitivity via lean muscle mass. Protein also has a high thermic effect, meaning it requires more energy to digest and process compared to other foods like carbs or fats.

How much protein do we need?

Unlike other macronutrients, our bodies don't have a storage reservoir for protein meaning we should be eating it regularly at each meal and snack.

We all need a different amounts of protein in our diet each day. Guidance suggests 0.8g/Kilo of body weight. For example if you weigh 10 Stone = 0.8g/63.5kg = 50.8g protein. However we are all individual, living with a different set of genetics and circumstances and there may be occasion where somebody’s protein requirements are increased, for example in athletes.