DIAAS is our preferred measure for comparing protein quality. It checks each needed amino acid after the protein is digested. That gives more detail than the older score, PDCAAS. If we want better information, we should ask for the better test.
A long acronym is not the benefit. Knowing what the body gets from a protein is.
What the older score misses
PDCAAS compares a protein's amino acids with a reference pattern. It then uses one figure for how well the whole protein is digested. That figure comes from the end of the gut. Scores are usually capped at 100%. [1]
That cap hides differences between sources above the limit. By that stage, gut microbes have already changed some of what is left.
These are reasons to ask for better data. A score we know well does not have to stay the final word.
What DIAAS does better
DIAAS checks each essential amino acid at the end of the small intestine. This is before microbes in the next part of the gut change the picture. It also allows scores above 100%.
That shows where a source has extra amino acids. These help fill gaps in another source. You get a closer look at each part of the protein. One broad figure hides more of that detail.
A review of the method explains these advantages and the remaining gaps in the data. [1]
Demand a score that belongs to the food
Ask what was tested. An ingredient score is not automatically the score of a finished bar. Ask which age group's needs formed the reference too.
Do not take a score from a raw ingredient, place it on a complex product and expect nobody to notice. Better measurement only helps when the number answers the right question.
A DIAAS score is not a trial of muscle growth in people. Some digestion data come from animal models. Keep those types of evidence separate.
Use protein quality and quantity together when shopping. Ask for DIAAS data on the food you want to compare. Then check the dose. A strong score attached to very little protein still does very little for your daily total.