Methionine Excretion. Effect of Diet and Methionine Ingestion in Normal Subjects

Abstract

Summary

Observations on a series of 80 normal male subjects, on a normal control diet, indicated an average daily urinary excretion of approximately 318 ± 9 mg of methionine. The increase in methionine excretion during the 6- and 24-hour periods following the ingestion of a 1.0 or 1.5 g supplement of methionine in addition to that of the usual protein intake only amounted to approximately 9 and 15% respectively of the intake of the free amino acid.

The ingestion for 4 days of diets of varying protein content showed no change in the daily urinary methionine excretion as a result of such variation. A decrease in the methionine normally excreted occurred when the subjects were on a high fat diet or when, on a 6-hour test, they were given a similar test supplement of methionine. Increased lipotropic requirements might account for the decrease in the loss of methionine after a 3-day fast or high fat intake.