Daily Urinary Nitrogen Partition and Balance in Infants with Kwashiorkor

Abstract

Partition of urinary nitrogen and complete nitrogen balance studies were conducted during the repletion of six subjects with kwashiorkor (infant protein malnutrition) who were eleven to twenty-eight months of age. Three of these infants were given milk ad libitum and three were given a lesser amount of milk followed by an isonitrogenous substitution of maize. A healthy, active child, forty-one months of age, living in a home environment and consuming a mixed diet ad libitum was also studied to provide an approximate comparison. As expected, the absolute excretion of urea by infants with kwashiorkor was reduced. The absolute excretion increased significantly in the infants given milk ad libitum but not in those given a lesser amount of protein. When urea excretion was expressed as a percentage of absorbed nitrogen, the increase in excretion for all infants was significant and began as soon as protein was introduced into the diet. The absolute excretion of ammonia by infants with kwashiorkor does not appear to be abnormal nor does there appear to be a trend in its excretion during repletion. The increased relative excretion (per cent of total urinary nitrogen), and subsequent decrease during repletion reflects changes in urea excretion rather than in the excretion of ammonia per se. Increased aminoaciduria was observed and correlated with nitrogen intake. When expressed as a function of tissue mass, amino acid excretion was abnormally high at the time of admission to the hospital and especially after refeeding but approached normal levels when cure was judged to be initiated. The excretion of uric acid by infants with protein malnutrition appears to be reduced at the time of admission to the hospital and to increase subsequently during repletion. The excretion of creatinine by the infants with kwashiorkor is much less than that of normal infants. The increase in creatinine excretion by the protein-depleted infants given milk ad libitum was significant after two weeks of refeeding whereas the increase in excretion by infants given lesser amounts of nitrogen was not significant. The excretion of creatine by infants with protein malnutrition at the time of admission to the hospital fell within the daily fluctuation of creatine excretion by the control subject. Creatine excretion tended to increase in infants given milk ad libitum and to decrease to values below those recorded for the control subject and for infants given lesser amounts of nitrogen. The excretion of undetermined nitrogen by the infants with kwashiorkor never fell outside the range of daily fluctuation observed in the control subject. There was a positive trend in excretion for the infants given milk ad libitum and no apparent trend in excretion in the infants given less nitrogen. The retention of nitrogen by infants with kwashiorkor is greater during the first two weeks of refeeding.