Milk leptin, adiponectin intakes affect growth of preterm infants

Exposures to milk leptin and adiponectin appear to have an impact on the growth of preterm infants, suggests a recent study.

“Human milk contains hormones that regulate metabolism,” the authors said. “Extrauterine growth restriction remains common among preterm infants, but the effect of ingesting milk hormones on preterm infant growth is poorly understood.”

This study quantified the associations of longitudinal exposure to leptin, adiponectin, and insulin in milk with physical growth of 50 preterm neonates (median gestational age 29.4 weeks). The authors sampled maternal milk on day-of-life 7, 14, 21, and 28 and measured hormone levels in whole milk by enzyme-linked immunosorbent assay. Milk leptin levels were available for a subset of 18 infants.

The authors calculated milk hormone doses by multiplying the hormone level by the milk volume ingested on each day and estimated the area under the curve (AUC) to show longitudinal exposure. Associations between milk hormone exposure and growth outcomes were analysed in generalized estimated equations.

Higher leptin intake resulted in greater weight gain (2.17 g/kg/day, 95 percent confidence interval [CI], 1.31–3.02) and weight z-score at 36 weeks’ postmenstrual age (0.30, 95 percent CI, 0.08–0.53 higher z-score per tertile). Higher adiponectin intake also correlated with greater length z-score (0.41, 95 percent CI, 0.13–0.69), but this association was nullified after adjustment for protein and calorie intake.

In addition, higher adiponectin showed an association with smaller head circumference z-score (–0.36, 95 percent CI, –0.64 to –0.07). No association was noted between insulin and growth outcomes.

“The long-term effects of milk hormones warrant further investigation,” the authors said.