Chrononutrition and Breast Milk: A Review of the Circadian Variation of Hormones Present in Human Milk

Abstract

IntroductionBreast milk contains a wide range of hormones, nutrients, and bioactive compounds. Chrononutrition looks at the interaction between food, both meal timing and meal composition, and circadian rhythms.MethodThis review is a continuation on series on chrononutrition and breast milk. All human studies published in English were included regardless of location or year of publication.ResultsThis review identifies the hormonal circadian variation researched in breast milk to date for melatonin, cortisol, cortisone, leptin, and insulin.ConclusionThe circadian variation observed in some hormones reinforces the superiority of breast milk over formula milk. Melatonin has been the most studied, but more research for all the hormones is needed due to various gaps in the literature and varying levels of study quality. There is insufficient evidence to make recommendations specifically targeting the lactating mother, but we identify and recommend several ideas for future research.

Melatonin in Human Breast Milk and Its Potential Role in Circadian Entrainment: A Nod towards Chrononutrition?

“…Again, this might be of even more critical relevance in infants born (extremely) preterm, in whom the peri-and postnatal stress following the state of prematurity may render them even more dependent on dynamically changing breast milk components. The almost exclusive practice of using expressed milk in intensive care units means that the infants are usually fed "circadian-mismatched" milk, i.e., milk fed to the newborn at a different time of day from when it is expressed [110,111]. The mistimed feeding practice may lead to chronodisruption, with, as already mentioned, an impact on the long-term health of the newborn.…”