Figure 1.

Amino acid composition of the intraduodenally infused whey protein hydrolysate (A) and increase of amino acid concentrations at 60 min during the 180 kcal whey protein infusion as a percentage of baseline in healthy younger (n = 10 (n = 9 for histidine); black bars) and older (n = 10; grey bars) men (B), ranked in order of high to low amino acid content (g/100 g). Essential amino acids: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. Branched-chain amino acids: isoleucine, leucine, and valine. Differences between older and younger men were determined using an independent sample t-test. Statistical significance was accepted at p < 0.05. * p < 0.05 older compared to younger men.