Effect of Breastmilk Leptin and Macronutrient Content on Gastric Emptying in Term Breastfed Infants

Abstract

Higher breastmilk casein concentration increases gastric emptying in preterm infants, however there are limited information regarding whether casein or other components of breastmilk affect gastric emptying in term infants. In this study we investigated associations of macronutrient and skim milk leptin concentrations with gastric emptying.Term fully breastfed infants (n=20, aged 6 to 32 weeks) were examined with ultrasound before and after one feed, and then at 10‐20 minute intervals until the next feed. Stomach volumes were calculated from transverse and sagittal ultrasound scans of the infant stomach. Milk intake was measured by the test‐weigh method. Breastmilk samples (1‐2 mL) were collected and analyzed for fat, lactose, total protein, whey and casein protein and skim milk leptin. Leptin dose was calculated as an average concentration multiplied by the feed volumeAfter accounting for the total feed volume and the time since the end of the feed post‐feed stomach volumes were not associated with leptin dose (P=0.998), leptin (P=0.91), fat (P=0.78), protein (P=0.80), whey (P=0.15), casein (P=0.37) or lactose (P=0.59) concentrations. Leptin dose was positively associated with protein (P<0.001) but not with fat (P=0.58), whey (P=0.76), casein (P=0.75) or lactose (P=0.77) concentration after accounting for the total feed volume.Gastric emptying in term infants does not appear to be affected by milk composition in the same way that it is in preterm infants.