Acid-Base Status in Dietary Treatment of Phenylketonuria

Abstract

Blood acid-base status, serum electrolytes and urine pH were examined in 64 infants and children with phenylketonuria (PKU) treated with 3 different low phenylalanine protein hydrolyzates (Aponti, Cymogran, AlbumaidXP) and 2 synthetic amino acid mixtures (Aminogran, PAM). The formulas caused significant differences in acid-base status, serum K and Cl and in urine pH. In acid-base balance studies in 2 patients with PKU, Aponti, PAM and 2 modifications of PAM (P2 + P3) were given. A change from mild alkalosis to increasing metabolic acidosis from Aponti (serum bicarbonate 25, 8 mval/l) to P3 (24, 0), P2 (19, 3) and PAM (17, 0) was observed. Urine pH decreased and renal net acid excretion increased. In the formulas PAM, P2 and P3 differences in renal net acid excretion correlated with differences in Cl and S contents of diets and of urines. New modifications of AlbumaidXP and of PAM showed normal renal net acid excretion (1 meq/kg per 24 h) in a balance study performed in 1 patient with PKU and normal acid base status in 20 other patients.