Effects of long-term low protein diet on albumin metabolism in chronic uremia.

The effects of long-term low protein diet on albumin metabolism of uremic patients were evaluated. Studies were performed on 62 patients divided into two groups depending on the duration of the diet (35 subjects from 6 to 30 days, 27 subjects from 6 months to 5 years). All patients received a diet containing at least 20 g of high biological value proteins per day. Albumin catabolism and distribution were measured by the two-tracer technique, after simultaneous i.v. injection of 131I-human serum albumin and of free 125I-iodide. Albumin synthesis was directly determined in 10 patients by two tracers, 14C-carbonate and 131I-albumin, according to the xanthydrol technique for specific activities of urea and albumin guanido carbon in plasma. The main features of albumin metabolism observed in both groups studied were: normal intravascular albumin mass, marked reduction of extravascular and total albumin pools, with proportionally reduced catabolism. No significant turnover difference was found between the first group and the patients on diet from 0.5 to 5 years, thus suggesting that dietary treatment per se is not responsible for the albumin depletion observed in chronic uremia.