3.1. A better measure of protein quality
An FAO expert working group convened in 2014 identified the ur- gent need to move forward with research protocols for more accurate protein quality evaluation (in press). This follows a previous FAO expert consultation that recommended a more accurate method to measure protein quality (FAO, 2013). The 2013 FAO report outlines recommen- dations relating to the new method known as the Dietary Indispensable Amino Acid Score (DIAAS) that will replace the Protein Digestibility Corrected Amino Acid Score (PDCAAS). As noted in this report although PDCASS is the method most commonly used to date, it is less than ideal on several counts and tends to overestimate protein quality, particularly in foods with lower protein quality. Specifically, PDCAAS overestimates the protein quality of plant proteins relative to animal proteins, with the result that it may appear that people consuming primarily plant pro- teins may be meeting their dietary requirement for protein and amino acids, when in fact they are not. With the improved measure DIASS, an- imal proteins score fairly consistently higher than plant proteins, in- cluding soy. Accurate protein quality measures are fundamental for many nutrition activities and more precise protein quality scores for various foods based on DIAAS are expected to be published.