Right Time, Right Milk: A New Key to Infant Health

Breast milk is more than just nutrition; it also carries natural signals that can guide a baby’s internal body clock. A recent study published in Frontiers in Nutrition suggests that storing breast milk for specific times of day and feeding it at the corresponding time could support infants’ circadian rhythms, which influence sleep, metabolism, and immune development.

Breast Milk as a Time-Sensitive Superfood

Breast milk is widely recognised as the gold standard for infant nutrition. It delivers not only essential vitamins and proteins but also subtle biological messages from mother to baby. These signals, such as hormones that follow day–night cycles, may help shape a newborn’s circadian rhythm, a system still developing in the first months of life.
However, many mothers rely on expressed milk, which is often stored and fed later. The new findings highlight why the timing of when stored milk is given may matter.

How the Study Was Conducted

Researchers at Rutgers University analysed breast milk samples from nearly 40 mothers. Small amounts of milk were collected at four points in the day: early morning (6 a.m.), midday (12 p.m.), evening (6 p.m.), and midnight (12 a.m.). In total, 236 samples were tested for several important compounds, including:

Melatonin and cortisol – hormones tied to circadian rhythm
Oxytocin – a bonding hormone
Immunoglobulin A (IgA) – an antibody supporting immunity
Lactoferrin – a protein involved in gut and immune health

Hormones That Follow the Clock

The analysis revealed clear daily patterns. Melatonin, which promotes sleep, was highest at night, while cortisol, linked to alertness, peaked in the early morning. These variations mirrored natural rhythms in the mother’s body and were passed along through her milk.
Other compounds like IgA and lactoferrin remained relatively steady throughout the day. Interestingly, these immune-related proteins were most abundant when babies were under one month old, suggesting extra early-life support for gut and immune development.

Why This Matters for Infants

Because infants’ circadian clocks are immature, these daily signals in milk may play a role in teaching their bodies the difference between day and night. Feeding milk collected in the morning at night or vice versa could potentially disrupt these cues.
Senior researcher Prof. Maria Gloria Dominguez-Bello explained that labelling bottles as “morning,” “afternoon,” or “night” could be a simple way to align feeding times with milk’s natural composition.

Practical Takeaway for Parents

While more research with larger groups is needed, the findings point toward a practical adjustment:

The label expressed milk by the time of day it was pumped.
Feed it at a matching time whenever possible.

This small step may help preserve breast milk’s built-in circadian signals, supporting babies’ sleep, immune function, and growth.

Conclusion

This study reinforces the idea that breast milk is not a static food; it changes throughout the day in ways that may benefit infants. By storing breast milk for specific times of day and feeding it accordingly, parents may help their babies’ circadian rhythm develop more naturally.

Source: Inputs from various media Sources

Priya Bairagi

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I’m a pharmacist with a strong background in health sciences. I hold a BSc from Delhi University and a pharmacy degree from PDM University. I write articles and daily health news while interviewing doctors to bring you the latest insights. In my free time, you’ll find me at the gym or lost in a sci-fi novel.