Biochemical study of malnutrition. Part IV. Determination of amino acids in the serum, erythrocytes, urine and stool ultrafiltrates.

Before dietary treatment, no significant differences, except for alanine, were found in the amino acid pattern for 22 young mothers and 33 children with protein-energy malnutrition (PEM), the characteristic feature of the serum pattern being the imbalance between essential and non essential amino acids. Apart from lysine, the essential amino acid levels were all below normal. This imbalance may be detected readily from the abnormal values of some particularly sensitive ratios: phenylalanine/tyrosine, valine/glycine, non essential amino acids/essential amino acids and, above all, serine/threonine. A striking finding was the very low threonine levels in all subjects, including local controls and the extremely low tryptophan levels in malnourished children. Before treatment, almost all the erythrocyte amino acid levels as well as the E/S ratios (erythrocytes/serum) were found to be raised in 9 children, demonstrating their poor clinical status. The urinary amino acid level was similar in both, patients before treatment and local controls. The urinary threonine level was low, like in the serum. A normalisation in most of the amino acid levels in the serum was observed upon dietary rehabilitation although not yet significant in all of them. In urine a similar tendency was observed but it was significant for threonine and methionine only, after 2 weeks treatment. Some additional urinary amino acid assays revealed changes upon two weeks dietary rehabilitation that can be interpreted as an increased production of enzymes affected by PEM as well as a growth of the patients' muscular mass. Increased free amino acid losses in the stools, caused by diarrhoea due to secondary malabsorption, and various viral and bacterial infections accompanying malnutrition, illustrate the severity of the diarrhoea.