Infant feeding

Feeding your baby is such an emotive topic, since the end goal is the same – a well, fed baby and a happy mother but there are so many different ways to get there. 

I personally feel that it is important for everyone to know what the scientific evidence is so that they can make an informed decision about the different options, and decide what feels best for them, and their situation. Whatever the mother’s decision, be it formula or breastfeeding, the majority of new mothers need support from healthcare providers, family, friends and the wider community.

What do we know?

There is now lots of evidence that breastfeeding is beneficial for your baby and is associated with a decrease risk of asthma1. Additionally, there is good quality evidence that the longer the duration of breastfeeding, the greater protection from obesity2,3. The link with breastfeeding and increased intelligence has long been suggested, but with some concern that some of the effect might be due to other confounders, however this is now thought to be a real association that persists into adulthood4 .

The gut microbiome refers to all the microorganisms that live in the gut and are now known to play a significant role in long-term health. It has recently been shown that formula milk, changes the composition of these organisms3. Such a change has been associated with a higher risk of subsequent obesity at 12 months of age2,3. Similar findings of disruption of the microbiome and subsequent increase in obesity have already been shown in mouse models5. We don’t yet know how important these findings are long term, and if there is an association with adult obesity. This could be important for mothers who chose to mix feed their babies, but are not aware that addition of formula despite breastfeeding has a similar effect on the microbiome to babies whom are exclusively formula fed. 

There is also evidence that breastfeeding benefits the mother too

Additionally there are also benefits of breastfeeding for mum, with decreased risk of developing type 2 diabetes, and breast and ovarian cancers4.

If all nearly all babies were exclusively for the first 6 months, 823000 deaths per year in children younger than 5 years and 20000 deaths per year from breast cancer could be prevented4.


There is now lots of evidence that breastfeeding is better than formula feeding yourself and your baby, but we still have more to learn about the long-term effects of breastfeeding on modulation of risk of disease and the microbiome. Most striking is the effect on the microbiome and possible long term health of the baby from combination (breast and formula) feeding. Amongst my clients, colleagues and mummy friends, this is rarely known. Instead mothers believe because they are primarily breastfeeding, they are doing the best for their baby. The challenges some mothers face establishing and persisting with breastfeeding must not be overlooked. However you chose to feed your baby is a very personal choice and should be made without judgement by society. I believe it is important though, that mothers have access to this unbiased scientific evidence so they are able to make an informed decision for themselves as ultimately a fed baby and happy mummy are best.


1.      Le Huërou-Luron, I., Blat, S. & Boudry, G. Breast- v. formula-feeding: impacts on the digestive tract and immediate and long-term health effects. Nutr Res Rev23, 23–36 (2010).

2.      Mueller, E. & Blaser, M. Breast milk, formula, the microbiome and overweight. Nat Rev Endocrinol14, 510–511 (2018).

3.      Forbes, J. D. et al.Association of Exposure to Formula in the Hospital and Subsequent Infant Feeding Practices With Gut Microbiota and Risk of Overweight in the First Year of Life. JAMA Pediatr172, e181161–e181161 (2018).

4.      Victora, C. G. et al.Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect. Lancet387, 475–490 (2016).

5.      Cox, L. M. et al.Altering the Intestinal Microbiota during a Critical Developmental Window Has Lasting Metabolic Consequences. Cell158, 705–721 (2014).

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