Body composition during long-term treatment of uremia with amino acid supplemented low-protein diet.

The influence on body composition of prolonged treatment with low-protein diet (20 g/day) supplemented with the essential amino acids and histidine was studied in 49 patients with chronic renal failure and uremic symptoms. Total body potassium (TBK) was measured with 40K in a whole-body counter. Total body water was determined with dilution of tritiated water. Predicted values for TBK and total body water were obtained from a reference population of 476 healthy subjects. In 38 patients investigated before treatment body weight was normal while mean TBK was 91% of predicted in men and 100% in women. Mean total body water was 104% of predicted in both men and women. Thirty-one patients were investigated at 3-month intervals during treatment for up to 12 months. No significant changes in mean body weight, TBK, or total body water were found. However, in 10/13 patients TBK decreased significantly, presumably due to increased catabolism in connection with intercurrent disease or insufficient energy intake. In the absence of complications long-term treatment with a low-protein diet and essential amino acids in renal failure seems to maintain body cell mass reflected in unchanged TBK.