Taurine supplementation prevents hyperaminoacidemia in growing term infants fed high-protein cow's milk formula

Blood urea nitrogen (BUN) and plasma and urine amino acid concentrations were compared between three cohorts of healthy growing term infants who were breast-fed (BF) or randomly assigned to one of two formulas either taurine non-supplemented (FF) or taurine supplemented (FF + T). The infants were studied from 2 to 12 weeks of age. Weight gain and growth in length was normal and similar in all three feeding groups during the study interval. At 12 weeks BUN was significantly higher in the FF group than in the BF and FF + T groups, 16.5 mg/dl vs 7.0 and 7.3 mg/dl, respectively. Total plasma amino acids (FF group: 240.5 ± 110.1 μmoles/dl; BF group: 180.1 ± 28.7 μmoles/dl; FF + T group: 182.3 ± 89.4 μmoles/dl) and total essential amino acids (FF group: 89.8 ± 37.3 μmoles/dl; BF group: 56.1 ± 16.3 μmoles/dl; FF + T group: 53.0 ± 24.2 μmoles/dl). The urine amino acid concentrations reflected the plasma levels in all groups. These results indicate that taurine supplementation to a high protein formula lowers BUN levels and the plasma and urine amino acid concentrations by some yet unknown mechanism to concentrations similar to those found in breast-fed infants with a much lower protein intake.