According to new research, breast milk in the morning is different from breast milk in the evening. An explanation for the fact that some babies take their nights late In order not to disturb the biological clock of the child, it is therefore advisable to breastfeed and, for mothers who express their milk, not to mix the bottles.
“Breastfeeding is the ideal way to provide infants with all the nutrients they need to grow and develop in good health,” writes the World Health Organization (WHO). Science regularly praises the merits of breastfeeding, whether it is to stimulate the brain development of premature babies, boost the child’s immune system or even prevent breast cancer. Even today, a study published in the journal Nature highlights the advantage of breastfeeding compared to expressed milk: it would not disturb the biological clock of the child. Because morning milk differs from evening milk, which could explain why some babies sleep through the night quickly while others wake their parents up for several months.
In detail, the mother’s morning milk is on average three times more concentrated in cortisol, the stress hormone, than that of the evening, which would make it more energizing, discovered researchers from the University of California (States -United). In the evening, on the other hand, it would contain more melatonin, the sleep hormone. It would therefore be more soothing, signifying to the newborn that it is time to sleep.
“These observed differences in children’s diets could explain why there is such variability in the development of the daily rhythm from child to child,” notes Dr. Jennifer Hahn-Holbrook, lead author of the study. “Human biology follows recurring daily rhythms that are governed by circadian cues in the environment. Here we show that human milk is a powerful form of ‘chrononutrition’, formulated to communicate information about the time of day to infants,” she continues.
Like turning on the light before going to bed
Also, for the researchers, this means rethinking the way babies are fed, especially for mothers who express their milk. “Milk ingestion at the wrong time can disrupt the development of infant circadian rhythms, which can contribute to sleep problems and decreased physiological attunement with their mother and environment. Dysregulated circadian biology can compromise infant health and development,” they wrote.
Also, “giving a baby a bottle of morning milk at night, with its high cortisol and low melatonin levels, could be the nutritional equivalent of turning on the light just before bed.”
This is only preliminary work, however, the scientists note, calling for further research. But if these results are confirmed in the future, there “is a very simple solution”, they assure: “mothers can, for example, label their milk according to the time at which it was drawn and coordinate the bottles by giving morning milk in the morning, and evening milk in the evening”.
Simple and inexpensive interventions
And to conclude: “despite broad public health implications, the timing of milk delivery has been the subject of few empirical studies, and no major pediatric or public health organization has formulated recommendations regarding the circadian matching of milk. However, the potential adverse developmental and health consequences could be mitigated by simple and inexpensive interventions to label and match milk stored in human milk.”
In France, health authorities advise mothers to exclusively breastfeed their children for six months for “optimal development”. “Exclusive breastfeeding protects the newborn from gastrointestinal infections and, to a lesser extent, from ENT and respiratory infections. The protective effect of breastfeeding depends on its duration and its exclusivity. Exclusive breastfeeding for 6 months versus 3-4 months allows for optimal infant development and should therefore be encouraged,” they write. But if they give information on the recommended frequency of feedings and the distances to be respected between them, no specific schedule is mentioned.
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