Why breastfed babies have improved immune systems?

New insight into the biological mechanisms of the long-term positive health effects of breastfeeding.


Breastfeeding is known to be related to better well-being results in infancy and all through adulthood. A past study has also shown that exclusive breastfeeding can reduce the risk of developing asthma, obesity, and autoimmune diseases later in life.

A new study by the University of Birmingham and Birmingham Women’s and Children’s NHS Foundation Trust shed light on the biological mechanisms of the long-term positive health effects of breastfeeding in preventing disorders of the immune system in later life.

Scientists, for the first time, discovered a specific type of immune cell that expands in the first three weeks of life in breastfed human babies. The immune cells called regulatory T cells are nearly twice as abundant as in formula-fed babies.

These cells also control the baby’s immune response against maternal cells transferred with breastmilk and help reduce inflammation. The study also shows that specific bacteria, called Veillonella and Gemella, which support regulatory T cells’ function, are more abundant in the gut of breastfed babies.

Senior author Gergely Toldi, a researcher at the University of Birmingham and consultant neonatologist at Birmingham Women’s and Children’s NHS Foundation Trust, said: “The influence of the type of milk received on the development of the immune response has not previously been studied in the first few weeks of life.

“Before our research, the outstanding importance and the early involvement of this specific cell type in breastfed babies were unknown.”

“We hope this invaluable new insight will lead to an increase in rates of breastfeeding and will see more babies benefit from the advantages of receiving breastmilk.”

“Furthermore, we hope for those babies who are formula-fed, these results will contribute to optimizing the composition of formula milk to exploit these immunological mechanisms.”

“We are very grateful for the mums and babies who contributed to this special project.”

For the study, scientists analyzed the data from 38 healthy mothers and their healthy babies. They collected small amounts of blood and stool samples at birth at Birmingham Women’s Hospital and then again later during home visits when the babies were three weeks old.

Sixteen out of the 38 babies (42%) were exclusively breastfed for the study duration, while nine babies received mixed feeding, and 13 babies were solely formula-fed.

Scientists are now planning to further study the same biological mechanism in sick and pre-term newborn babies who have developed inflammatory complications.

Journal Reference:
  1. HL Wood et al. Breastfeeding promotes early neonatal regulatory T cell expansion and non‐inherited maternal antigens’ immune tolerance. DOI: 10.1111/all.14736


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