Breastfeeding and the microbiome

Breastfeeding and the microbiome

‘Does it make any sense to continue giving the breast now that I have used a breastpump?’

It was obvious my client had read an article in the NRC newspaper on research outcomes  on microbiome and breastfeeding. She had not digested all the details but the gist was clear: after expressing with a pump once the microbiome of breastmilk supposedly changed for the worse. There would be more dangerous-sounding bacteria in her milk, and less biodiversity, and the effect would be lasting. This gave her the impression that breastfeeding after expressing as she had done was useless.

And another mother asked ‘I read in the NRC that my baby can get astma because I expressed milk, is that true?’

The newspaperarticle did indeed give this impression. No idea why the journalist and or editors chose to use this perspective. Because the researchpaper did show changes in microbiome after expressing that same research did not imply that this was the main outcome. Other conclusions are just as warranted based on the original paper. For example:

  • Breastfeeding is a complex interaction between mother and child: even at bacterial level there is an exchange between breast and external environment. The microbiome in the breast is clearly not only developed within the mothers own body, but responds to conthe external input by for example either baby or pump.
  • Handexpression has its merits: it leads to less changes in the microbiome compared to expressing with a breastpump.
  • Expressing with a pump does lower the biodiversity of bacteria in breastmilk, but that does not mean the milk turns sterile or even spoils: there are many more living cells in breastmilk that are geared towards the health of the baby than there could be in formula.
  • Expressed breastmilk appears to increase the chance of the baby developing astma to levels similar to babies given formula. Not higher than.

The mentioned bacteria (enterococci and e-colis) that were found in breastmilk after expressing with a breastpump are bacteria that can survive in an environment with oxygen, which a lot of bacteria cannot. Therefore is it unsurprising that these survived the contact with the external environment and could colonise the milk. Most healthy people are carriers of these bacteria without getting ill-effects or illness. Research into the microbiome has resulted in may associations but we do not yet know much about how and when which bacteria have an effect on our health for better or worse.

In summary: Breastfeeding and mothersmilk are a special and specialised process of which we do not yet understand the ins and outs. What does emerge from recent reseach is a vastly more specialised and complex product than was assumed.

I do hope journalist at NRC will realise how negatively their report on this interesting and well designed fundametal researchproject may have impacted on their readers.

I do hope that it is clear that breastfeeding and mothersmilk are worthy of respect and effort. Fundamental research like this leads, as the researchers conclude, to more questions. And not to quick conclusions in a newspaper.

And certainly not because there are many questions about the research too. For exapmle: who were the women who never used a breastpump? If these women lived in the western world they must have been a special group. May these women have had an unusual microbiome? Did they have a different socio-economic status? Did they live in a different environment? The paper does not go into these aspects.

And to make it even more interesting for future research, it was also found that the microbiome is different for boys and girls. How? Why? Not clear yet.

These open questions do not diminish the complexity of the reseach and the mothersmilk and breastfeeding that were the subject of it. On the contrary. The complexity and our limited knowlegde makes it clear that breastfeeding deserves carefull handling by parents, healthcare professionals and clearly also by journalists.

And yes, it appears to make sense to keep our breastpumps well cleaned. Just in case, you know. Won’t do any harm.


P.s. the image comes from a madonna lactans attributed to Elisabetta Sirani