FHW Wong, CY Yeung, AYC Tam, HC Kwan

Abstract

Breath hydrogen response to oral lactose was studied in 89 neonates of Chinese origin, 54 term and 35 preterm. End-expiratory air samples were collected with an automatic electronic device newly developed by the authors. Breath H₂ was analyzed with Shimadzu gas chromatograph. Post-lactose rise in breath H₂ of 20 ppm appears to distinguish two populations of infants, namely the lactose-absorbers with lower rises and the mal-absorbers with higher rises. Preterm infants showed much higher frequency of lactose mal-absorption as indicated by excessively high breath H₂ response, a feature compatible with immature lactase development. Although given similar amount of lactose for the test, infants taking formula showed significantly lower breath H₂ response than taking freshly prepared lactose solution. Slower gastric emptying with formula may be a reason for the difference. 97% of healthy term infants and 92% of healthy preterm neonates showed no evidence of lactose-malabsorption when fed the usual 7%-lactose-containing formula by the breath H₂ response test.