Supplements containing amino acids and keto acids in the treatment of chronic uremia.

Three mixtures containing varying proportions of threonine, tyrosine, and the ornithine, lysine, and histidine salts of branched-chain keto acids have been tested as dietary supplements to a 20- to 25-g mixed-quality protein diet in patients with severe chronic uremia. Two of the three supplements improved the abnormalities of plasma amino acid concentrations, and slowed or arrested progression of renal insufficiency. The second supplement, which contained less threonine and lysine, led to subnormal plasma concentrations of these two amino acids and aggravated hypophosphatemia. The third supplement, which also contained a small amount of the hydroxy analogue of methionine, was the most effective in slowing progression. The results emphasize the importance of optimizing the composition of such supplements.