Protein is a crucial component of any diet, regardless of your health and performance goals. It provides the raw material for growth, maintenance, and repair, and makes up the enzymes that facilitate practically all metabolic reactions in the body. Getting the right amount of protein of the right quality is critical to optimising physical and mental function.

What is protein?

Protein is an essential nutrient that mainly serves as the “building blocks” for the cells in our bodies. It is a broad term that accounts for a vast number of molecules. Protein structures are made up of combinations of 21 smaller molecules, called amino acids. Aside from structural and functional roles, protein can also be broken down to function as a source of energy [1].

Amino Acids

Amino acids are the smaller molecules that combine to form protein structures. There are 20 main amino acids, and they are categorised based on our ability to synthesise them in our bodies.

Essential amino acids are those that we are unable to synthesise. These amino acids must be provided through our diets to sustain life and therefore are regarded as nutritionally essential [4]. There are 9 essential amino acids [5].

• Histidine
• Isoleucine
• Leucine
• Lysine
• Methionine
• Phenylalanine
• Threonine
• Tryptophan
• Valine

Non-essential amino acids can be made via specific processes in the body; however, they can also be obtained through the diet to maintain optimal levels [6].

• Alanine
• Aspartic acid
• Asparagine
• Glutamic Acid

Conditionally-essential amino acids are categorized based on the body’s demand for them increasing under certain situations (such as injury or infection) [6].

• Arginine
• Cysteine
• Glutamine
• Tyrosine
• Glycine
• Proline
• Serine

Aside from being the essential component for the formation of proteins, amino acids have many additional functions throughout the body and are highly involved in optimising metabolic pathways.

Protein quality & DIAAS

Different protein sources have different amino acid compositions, which can impact their overall effectiveness for human nutrition. This balance of amino acids is called the “amino acid profile”. Ideally, the amino acid profile of a protein would mimic that of human dietary requirements, especially when it comes to essential amino acids. Proteins that contain adequate amounts of essential amino acids are often termed “whole proteins”.

DIAAS stands for Digestible Indispensable Amino Acid Score and is a method of measuring protein quality. Effectively, it evaluates the proportion of consumed amino acids absorbed and utilised by the body. It compares the amount of each essential amino acid absorbed from a protein source to a reference value for the human body [7]. Generally, the lowest score of the nine essential amino acids determines the overall DIAAS score, which makes it a good measurement for identifying a “whole protein”. DIAAS is considered the gold standard for protein quality evaluation, as it accounts for both the amino acid profile of a protein and its digestibility [7].

The role of protein in the body

The protein family is hugely diverse, and as such, there are many functions that proteins play in the body.

Growth, maintenance, and repair of tissues. Excluding water and fat, practically everything in the body is made of proteins. This includes your brain, muscles, bones, skin, and internal organs. When more of these tissues need to be made, whether it be for growth, maintenance, or repair, protein provides the raw material for the process [1]. They also provide structure to cells and tissues, maintaining their stiffness and rigidity [2].

Biological machines.Proteins make up the structure of enzymes, the biological machines that help facilitate chemical reactions in our bodies. Almost all body functions rely on enzymes in some way, including digestion, energy metabolism, and muscle contraction, to name a few [2].

Energy source.Despite carbohydrates and fats providing the body’s primary energy sources, protein can also be metabolised if needed to provide energy for cellular processes and bodily functions. This is particularly important in physically demanding situations, as the utilisation of other nutrients may be at capacity. In this case, the body may need to draw on protein stores to provide extra energy for your cells [3].

Practical applications

Protein is a popular topic in the nutrition field, but sometimes it can be difficult to know where to source it and how much your body actually needs.

As it forms nearly all biological structures, we must provide enough protein through our nutrition to build, maintain, and repair our bodies for maximised performance. In doing this, structures such as muscles and bones will be able to handle the demands of life, training, and competition.

As these structures become stressed and even damaged in the pursuit of performance, it is vital to provide an adequate amount of protein to repair them and to recover and adapt optimally. High protein diets are often associated with skeletal muscle maintenance and development, crucial in most athletic disciplines [3].

As well as being sufficient in protein, a well-balanced diet should provide an adequate combination of amino acids to match the demand for metabolic pathways and protein synthesis. It is important to provide your body with essential amino acids, as they cannot be obtained outside dietary means [4]. Consuming whole proteins with a complete and balanced amino acid profile will ensure your body gets the necessary components to optimise its metabolic function. When it comes to peak performance, protein quality (and not just protein quantity) is an essential factor to consider within your diet.

The radix solution

At Radix, we strive to create the best quality products for the best possible performance. With a focus on nutrient density, the Radix Nutrition Architecture (RNA) includes a daily target for overall protein quantity as well as each amino acid, based on the most up-to-date nutrition science recommendations. When it comes to quality, we use the DIAAS scale to guide our protein design, ensuring that our meals and supplements have outstanding digestibility and amino acid profiles. Currently, our whey and plant-based proteins have industry-leading DIAAS scores of 1.61 and 1.30 respectively. All this ensures that a Radix diet will supply your body with the building blocks it needs to perform and recover at its absolute best.