DIFFERENTIAL-EFFECTS OF SUCROSE, FRUCTOSE, GLUCOSE, AND LACTOSE ON CRYING IN 1-DAY-OLD TO 3-DAY-OLD HUMAN INFANTS - QUALITATIVE AND QUANTITATIVE CONSIDERATIONS

This study assessed the potency of different sugars as calming agents in human infants. Five 0.1-ml aliquots of 0.51M sucrose, fructose, glucose, or lactose were presented to 1- to 3-day-old infants who were crying spontaneously. Sucrose and fructose were equally effective calming agents, glucose slightly less so. Lactose, the milk sugar, was not at all effective and did not reduce crying any more than did water. In fact, some babies cried more when given lactose. A second experiment established quantitative, dose-response functions for sucrose as a calming agent: 0.17M, 0.42M, and 0.5 IM sucrose reduced crying equally effectively. Moreover, crying reduction was not differentially affected by the volume of ingested sucrose, because 0.2 ml of 0.34M sucrose was as effective as 0.6 or 1.0 ml of 0.34M sucrose. Results suggest that sucrose calms in a stepwise manner with a flat suprathreshold function and that the calming basis of milk must be sought in components other than its sugar.