Breast milk is the sole source of nutrients for newborn infants. Beyond its nutritional benefits, researchers have discovered another fascinating aspect: the composition of breast milk changes throughout the day, helping regulate the baby's circadian rhythm—the physical, mental, and biological changes our bodies undergo over 24 hours.
In newborn infants, circadian rhythm develops only after three months of life. Until then, breast milk plays a crucial role in transmitting the mother's circadian cues to the baby through feeding. Intriguing, isn't it?
Dr. Joe, M.D., shared insights on his Instagram page (@drjoe_md) explaining how breast milk composition varies between day and night, as well as its implications for pumped milk.
During the day, breast milk contains higher levels of cortisol and activity-promoting amino acids. Cortisol, often called the "alertness hormone," helps keep the baby more active and attentive during the day.
At night, cortisol levels drop, and melatonin—a hormone that promotes sleep and relaxation—is more abundant in breast milk. This nighttime composition helps the baby relax and sleep better.
When infants are directly breastfed, they benefit from these dynamic changes aligned with the mother's circadian rhythm. However, in today's modernized world, breast milk pumping has become more common, potentially influencing the baby's sleep cycle.
In today's fast-paced world, many working mothers prefer to pump breast milk and store it for later use. Dr. Joe highlights that feeding daytime-pumped milk to babies at night may disrupt their sleep due to its composition not matching the time of day.
While this phenomenon is fascinating, scientists are still unclear about the extent to which these changes impact a baby's sleep, as this area remains understudied.
Breast milk is not just a source of nutrition for newborns; it also plays a vital role in regulating their circadian rhythms and fostering a strong bond between mother and child. Exclusive breastfeeding for six months to three years is recommended. Understanding the dynamic nature of breast milk can contribute to healthier growth and development for babies.
Reference:
1. Hahn-Holbrook, Jennifer, Darby Saxbe, Christine Bixby, Caroline Steele, and Laura Glynn. "Human Milk as 'Chrononutrition': Implications for Child Health and Development." Pediatric Research 85, no. 7 (2019): 936–942. Accessed December 28, 2024. https://doi.org/10.1038/s41390-019-0368-x.
MSM