Diving into the data: should we breastfeed to save the planet?

Recently, an editorial in the British Medical Journal argued that investment in breastfeeding support was an urgent step in combating climate change. The main point of the thesis was that the manufacture, transport and preparation of infant formula have a much more detrimental impact on the environment than breastfeeding, therefore the government should invest in breastfeeding support so that parents can reduce their reliance on formula.

On the face of it, it seems obvious that feeding babies food that has to be made, transported and heated prior to use would have more of an environmental impact than breastfeeding, which requires none of those things. On the other hand, breastfeeding does use up a fair amount of calories and the extra food required by a breastfeeding Mum to significantly increase her calorie intake must have an environmental impact too. 

As an eternal geek, I wondered how the data presented by the authors in favour of their argument stacked up, so I took a nosedive into their references list to get to the bottom of some of the key claims made in the editorial. Here’s what I found:

Claim: Breastfeeding for six months saves 95-153kg CO₂e (carbon dioxide equivalents) per baby compared to formula feeding 

The research study cited by Joffe et al and again in the Conversation piece that followed did indeed show that breastfeeding for 6 months would save 95-153kg CO₂e (carbon dioxide equivalent) compared to formula feeding. You know big buts are our jam, so here it is; the data was based on a mathematical model that was dependant on the information provided by the researchers. This is crucial because when the study researchers adjusted the weighting of individual components of infant formula within their model, the outcome was very different; it resulted in a 12-36% reduction in the climate impact of formula. The study doesn’t explain this fully but we can assume that the impact of formula feeding would then range from 4 – 24% higher than breastfeeding. Quite a bit less than the 40% reported. Even more striking is that the study authors went on to say that if the model was adjusted based on protein content of formula and no sterilisation of bottles was assumed, the impact of formula feeding would actually be lower than breastfeeding in all the countries studied, including the UK! 

Claim: If all babies were breastfed for just six months in the UK, the carbon emission savings would equate to removing between 50,000 and 77,500 cars from the road for a year. 

We’re not entirely sure how this one was calculated. It was likely based on the values from the research paper described above which in itself suggests a re-evaluation for the reasons we’ve explained. I did try to replicate the calculation though and failed miserably! I’m not sure if my assumptions are correct so please let me know if I’ve missed something. This is what I came up with:

In 2018 there were 731,217 babies born in the UK (657,076 in England and Wales, 51,308 in Scotland and 22,833 in Northern Ireland).  If we assume that the above data is spot on – which we’ve already described is unlikely – and that breastfeeding for six months will save the maximum 153kg CO₂e per baby, then we would save just under 112 million kg (or 112,000 tonnes) CO₂e per year. The carbon calculator cited by the editorial suggests that’s equivalent of 23,779 cars off the road for a year.  

Claim: In the UK, the estimated energy cost of boiling this water over the first year of a baby’s life equates to over 1.5m kilograms of carbon dioxide.  

The paper cited as evidence of this is actually a review about the impact of the UNICEF Baby Friendly Initiative and makes no mention of boiling the kettle whatsoever that we can see.  We have no idea how this figure was arrived because the estimates we could find online range from 15g to around 43g carbon produced per kettle boil and we couldn’t find a definitive value anywhere, particularly in the scientific literature. The actual carbon produced by a single kettle boil is dependent on the energy efficiency of your kettle, whether you boil just the water you need or more and the type of heating you have. Any calculation of the impact of boiling the kettle specifically for making up infant formula will depend on these factors as well as on whether parents make up bottles individually or in batches and how much ready to feed formula is used.

Claim: Research shows 550m infant formula cans, 86,000 tons of metal and 364,000 tons of paper are added to landfills every year.

The paper cited in support of this claim actually didn’t measure this, it was a review paper that cited an International Baby Food Action Network web page as evidence. We would love to have checked it out but the page is no longer available online. If you have a copy, please can you send it our way. Again, the actual value will depend on the number of cans of formula purchased versus cardboard tubs and the proportion of parents recycling them. If you want some cool ideas for recycling formula cans, check out Pinterest. I turned mine into a fetching makeup brush holder!

Conclusion: It’s clear that reducing our reliance on formula where possible is an important step in helping mitigate the climate crisis.

Well actually, based on the evidence presented by the authors in their editorial it’s not that clear that reducing formula use would have such a great impact on our environment. We’re not sure exactly what the carbon footprint of formula use for six months is, let alone how it stacks up against breastfeeding, combi-feeding or the use of donated breast milk over the recommended two years. 

So, what now?

It’s clear that families are in desperate need of improved infant feeding support across the board and we commend anyone who, like us, works towards the goal of compassionate, science based infant feeding education and support for everyone #bottlesboobsortubes! What we need though, are robust, evidence based solutions that benefit all families. Using the impact of formula on the environment as a basis for informing infant feeding investment only supports investment for exclusively breastfeeding women, and based on the data cited in the editorial would likely challenge the viability of pumping or using donated breastmilk. While the intentions – to galvanise support for breastfeeding – are honourable, we fear that this approach may lead us back to the all too familiar scenario where, despite little or no evidence to support the claims, one infant feeding method is seen as the ‘correct’ choice and women are expected to do the right thing, this time for the good of the planet