Protein is an essential nutrient that mainly serves as the “building blocks” for the cells in our bodies. It is a crucial component of any diet, regardless of your health and performance goals. However, not all proteins are created equal. At Radix, we use the Digestible Indispensable Amino Acid Score (DIAAS) to drive innovation and ensure our protein formulations are of the best possible quality.

DIAAS stands for Digestible Indispensable Amino Acid Score and is a method of measuring protein quality. Effectively, it evaluates how effectively a protein source supplies each essential amino acid at the required level to the body following digestion. It does this by comparing the amount of each essential amino acid absorbed from a protein source to the reference value for the human body ^[1]. As the lowest ratio of the nine essential amino acids determines the overall DIAAS score, this final score serves as a proxy measure for the whole protein, providing information about whether or not a protein provides adequate amounts of all nine essential amino acids. 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 ^[1].

Up until recently, another method of protein quality evaluation was commonly used; the Protein Digestibility-Corrected Amino Acid Score (PDCAAS). This method functions similarly to DIAAS but has several drawbacks that make it less accurate and no longer appropriate.

The assessment of the nutritional value of a protein should reflect its ability to satisfy the metabolic demands for nitrogen and amino acids. Its capacity to do so is determined by amino acid availability and digestibility ^[1]. There are several reasons why PDCAAS does not adequately account for these factors.

First, PDCAAS is taken from faecal samples, where the presence of amino acids compared to what is consumed represents relative digestibility. This can lead to an inaccurate evaluation, as many processes in the gut can introduce amino acids into the faeces, such as the synthesis of methionine and lysine and microbial metabolic functions. This can result in “false positives” when measuring quantities of amino acids to determine absorption ^[1].

On the other hand, DIAAS samples are taken at the end of the ileum. This leads to greater accuracy when assessing digestibility, as amino acid absorption practically ceases once it reaches this point in the digestive tract ^[1]. Measurement at the end of the ileum also precedes the processes in the gut that can introduce additional amino acids.

Another factor to consider is that the PDCAAS system allows for a maximum score of 1. It does not permit extra nutritional value to be evaluated in higher quality proteins. Under the DIAAS method, a protein that exceeds the human requirements for all essential amino acids can score higher than 1. This makes it a more effective way to compare high-quality protein sources ^[1].

In 2011, the Food and Agriculture Organisation (FAO) recommended using DIAAS over PDCAAS for protein quality evaluation ^[1].

The following is a list of protein sources and their corresponding DIAAS score ^[1].

Here at Radix, we’ve used the theory of DIAAS to guide the development of the most effective, technologically advanced protein on the market.

Made from ultra-filtered whey protein isolate, ultra-filtered whey protein concentrate, & ultra-filtered milk protein concentrate, our whey protein complex has been designed to provide the highest amino acid profile across all essential amino acids with a DIAAS of 1.61. This was achieved through a technical partnership with Fonterra and by simulating over 50 formulations before finalising our blend.  

Made from precisely defined concentrations of yellow pea protein isolate and brown rice protein isolate, our plant protein complex is also designed to provide a complete amino acid profile with a DIAAS of 1.30. This scores higher than traditional pure whey isolate.

Using DIAAS to drive the improvement of our products, we have achieved protein formulations that have the potential to provide your body with the building blocks it needs to function at its best. By achieving a class-leading amino acid profile and ensuring high quality, our protein powders are now able to support optimal performance for athletes.