Breast Feeding and The Hot Topic Of Immunity

Written by Sonja Armstrong

Scientifically reviewed by
Dr Fathalla Ali, PHD Paediatrics


Is there a hotter topic than immunity in these Covid-19 times? As the global scientific community focuses on developing vaccines that confer immunity, we’ve become familiar with the concept of a compromised or ‘weakened’ immune systems. Less familiar is the concept of an overactive immune system, whose response to an infection (sometimes referred to as a cytokine storm) can be so overwhelming that it becomes life threatening. It is this overactive immune response to Covid-19 that has emerged and a complicating factor in an individuals’ response to the disease and their recovery (2).

Either way, immune systems that are underactive or overactive are out of balance, begging the question; “Why do some people have better regulated immune systems than others?”. There are myriad reasons for this including age, diet, lifestyle, medical conditions and so on but we know that the function of our immune system is heavily influenced by the diversity of the bacteria in our gut, our gut microbiome, and that the gut microbiome helps modulate our immune response to our environment and to disease (3). What does this have to do with breastfeeding?

A study conducted by the University of Birmingham and Birmingham Women’s and Children’s NHS Foundation Trust, considered a cohort of healthy mothers who variously fed their healthy newborns exclusively with breast milk, a mix of breast and formula milk and exclusively formula. After three weeks, stool and blood samples taken from the babies revealed that breast-fed babies produced higher levels of regulatory T cells (Tregs). These Tregs are cells that form part of the immune system and are associated with better immunity. Tregs were twice as abundant in the exclusively breastfed newborns when compared to the Tregs present in newborns fed with formula.

Also, more abundant in the gut microbiome of the breast-fed babies were some of Short Chain Fatty Acid bacteria that support the functioning of Treg cells, thus demonstrating their role in calibrating babies immune system.

What does that mean exactly? Well, Tregs regulate the body’s immune response to incoming invaders and even the response of the immune system to the body’s actions itself. They help the immune system to neither under nor over-react, promoting a Goldilocks ‘just right’ response. As such they’re involved in preventing autoimmune disease and mounting a ‘considered’ response to infections.

In sum, the study is an elegant possible explanation for why breastfed babies have lower rates of asthma and are at less risk of developing autoimmune diseases later in life.

The study’s scope was limited to the first three weeks of life. So what does the science say about how long to breast feed? Whilst most Australian women have adopted the Breast is Best mantra and up to 90% start off with baby-to-boob this drops dramatically with 61% of babies at 4 months being exclusively breast fed (4).

Science shows us that there are a myriad of benefits conferred by breastfeeding including the better functioning of the immune system and it’s ability to fight disease (5). The World Health Organisation (WHO) recommends 6 months exclusive breast-feeding, with no other foods or liquids provided, and a further couple of years of breastfeeding while transitioning to solids (6).

For some mothers breast-feeding is not simply a matter of sitting back and relaxing while you bond with your suckling child. Sometimes there are complications, and it may not even be an option, in which case your clinician may be able to advise on ways to support your breast-feeding efforts, and whether probiotic and prebiotic supplementation may help.


  1. Wood, H., Acharjee, A., Pearce, H., Quraishi, M. N., Powell, R., Rossiter, A., Beggs, A., Ewer, A., Moss, P., & Toldi, G. (2021). Breastfeeding promotes early neonatal regulatory T-cell expansion and immune tolerance of non-inherited maternal antigens. Allergy, 10.1111/all.14736. Advance online publication.
  2. Roxanne Khamsi, “Rogue antibodies could be driving severe COVID-19”, Roxanne Khamsi, Nature, doi:
  3. Wiertsema, S.P.; van Bergenhenegouwen, J.; Garssen, J.; Knippels, L.M.J. The Interplay between the Gut Microbiome and the Immune System in the Context of Infectious Diseases throughout Life and the Role of Nutrition in Optimizing Treatment Strategies. Nutrients 2021, 13, 886. 10.3390/nu13030886
  4. Australian Institute of Health and Welfare 2020. Australia’s children. Cat. no. CWS 69. Canberra: AIHW
  5. Whitten D, Breastfeeding, 2020, Advanced Clinical Naturopathic.
  6. World Health Organization (WHO) 2021,

Free meal planner

Subscribe to our newsletter to receive a free pre-pregnancy meal planner, prepared by a nutritionist.​

We send very occasional emails relating to gut health including studies, articles and more. We never share your information.​

Search MothersBabies

Looking for something in particular? Find it here using our search query function. Simply type in your keyword and click the icon.

Recent Articles

Join Us