Metabolic studies with keto acid diets

Abstract
Five patients with chronic renal failure taking a diet containing approximately 5 g N throughout were studied during two periods of 1 month each. Nitrogen balance, urea metabolism, and incorporation of 15N from urea into albumin on diet alone or with a keto acid/essential amino acid supplement were measured. Keto acids produced a reduction of plasma urea, urea synthesis, and urea excretion and an improvement in nitrogen balance. In patients who demonstrated the greatest change on ketoacids, 15N incorporation also increased, but their total incorporation of urea nitrogen was not nearly sufficient to account for the improvement in nitrogen balance. The role of keto acids in protein anabolism is not solely or even mainly explained by promotion of nonprotein nitrogen reutilization.