who suggested
that digestible amino acid values should be used
to avoid any differences in absorption efficiency arising
from the ingredient sources. Given that the ideal protein
level involves the optimal ratios of all the essential
amino acids to lysine, the regression analysis used Val/
Lys ratio, not digestible valine. Most studies that have
evaluated the Val/Lys ratio have first estimated the
optimal valine level and then used this level to find the
optimal Val/Lys ratio.