American Journal of Clinical Nutrition, Vol 27, 806-812, Copyright © 1974 by The American Society for Clinical Nutrition, Inc.

Nitrogen balance and plasma amino acid levels in uremic patients fed an essential amino acid diet

¹ From the Research and Medical Services, VA Wadsworth Hospital Center, and the Schools of Medicine and Public Health, University of California at Los Angeles

The nutritional value of a diet providing the eight essential l-amino acids was assessed in three chronically uremic men living in a metabolic unit. Subjects were fed initially, for comparison, a diet providing 22 g of primarily high quality protein and then received a diet containing 21 g of the eight free essential l-amino acids. Nitrogen balance was similar for each subject with both diets and was negative in two patients and neutral in one. Because nitrogen intake was less with the amino acid diet, it is inferred that dietary nitrogen was utilized more efficiently with the latter diet. Levels of both essential and nonessential amino acids in plasma were well maintained with the amino acid diet. Exceptions were cystine and histidine which decreased, and valine and possibly threonine, which increased with the latter diet. Plasma cystine was initially elevated and the metabolic significance of its fall is obscure. The decrease in plasma histidine supports the contention that histidine is an essential amino acid in uremia. These observations suggest that a diet providing 21 g of the eight essential l-amino acids may not be adequate for the maintenance of good nutritional status in renal failure. Addition of histidine and possibly a source of nonspecific nitrogen may enhance the nutritional value of this diet.