Human Milk Glucocorticoid Levels Are Associated With Infant Adiposity and Head Circumference Over the First Year of Life.

Shikha Pundir,Clare R. Wall,Zoya Gridneva,Avinesh Pillai,Donna T. Geddes,Eric B. Thorstensen,David Cameron-Smith

doi:10.3389/fnut.2020.00166

Abstract

Human milk (HM) is a complex and dynamic biological fluid, which contains appreciable concentrations of the glucocorticoids, cortisol and cortisone. Experimental studies in non-human primates suggest the HM glucocorticoids' impact on infant growth and body composition. In this current study, analysis is made of the relationships between HM glucocorticoid concentrations and the infant growth and development over the first year of life. HM was collected by lactating healthy women (n = 18), using a standardized protocol, at 2, 5, 9, and 12 months after childbirth. Cortisol and cortisone concentrations in the HM were measured using liquid chromatography mass spectrometry. Infant weight, length and head circumference were measured by standard protocols and percentage fat mass (% FM) determined by whole body bioimpedance. Cortisol and cortisone concentrations were unaltered over the analyzed lactation period (2–12 months), and were altered by infant sex. Although, HM cortisol was positively associated with infant percentage fat mass (% FM) (p = 0.008) and cortisone positively associated with infant head circumference (p = 0.01). For the first 12 months of life, the concentration of HM glucocorticoids levels was positively associated with infant adiposity (%FM) and head circumference. This preliminary evidence provides insight to a possible relationship between ingested HM glucocorticoids and infant body composition. Further studies are required to determine the mechanisms regulating HM glucocorticoids.

Highlights

Nutrition during the first 1000 days of life, a period from conception to the child’s second year, has a major impact on the infant’s growth and development [1]
One male infant ceased breastfeeding 8 days before the 12-month appointment, one male infant was being weaned at the time of 12-month appointment, no samples were provided; one female infant stopped at 10 months after birth; these three infants were measured at the time of the 12-month appointment
Averaged across the sampled cohort, there was no consistent pattern in the Human milk (HM) glucocorticoid concentrations throughout the first year of lactation

Summary

Introduction

Nutrition during the first 1000 days of life, a period from conception to the child’s second year, has a major impact on the infant’s growth and development [1]. It is during this critical period of life where subtle changes in growth and developmental trajectories can have substantial impact on the health of that individual later in life, including obesity and non-communicable disease risks through childhood and into adulthood [2, 3]. Human milk (HM) is complex and dynamic, containing nutritive factors [9], and being recognized as a rich source of hormones, which have been demonstrated to impact directly or indirectly on infant body functions [10]. Amoungst infants where HM is the predominant source of nourishment for the first year of life, subtle variation in HM composition, may modify early growth, and development

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