The Effect of Methionine upon the Urinary Nitrogen in Men at Normal and Low Levels of Protein Intake

Abstract

Experiments have been carried out on human subjects during 10-day periods, to test the effects of added methionine on urinary excretion. Diets supplying 2000 Cal. and 75 gm of protein (Diet A), 2000 Cal. and 14 gm protein (Diet B), 1200 Cal. and 5 gm protein, or 600 Cal. and 5 gm protein (Diet C), were employed. In no instance did the addition of 3 gm of dl-methionine per day to the low-protein diets decrease the urinary nitrogen excretion. Under the conditions employed, methonine alone does not spare body protein, nor is there any evidence of its utilization from values for the nitrogen or sulfur excretion. The nitrogen minimum (“wear and tear quota”) cannot be obtained when the Caloric intake is 600 or 1200 Cal. daily although it is obtained when 2000 Cal. per day are given.