Research shows that probiotics can help when your breastfed baby cries and fusses a lot

Research shows that probiotics decrease the amount of time that breastfed babies spend crying and fussing. All probiotic strains seem effective, but Lactobacillus reuteri DSM 17938 has been shown to be the most effective.

Probiotics have not been shown to have this effect in fussy babies who are formula-fed.

Having said this, many or even most of the families I've seen over the years are already giving their baby a probiotic when they come to see me, yet their little one has continued to cry and fuss a great deal. It's only once we work together through the Possums five domain approach to crying and fussing, which includes The Possums Sleep Program, and important elements of Possums Breastfeeding & Lactation, that we start to see a much more dialled down baby. You can find out about the five domain approach starting here.

Do probiotics work by changing your baby's gut microbiome?

Often it's said that probiotics work by changing the gut microbiome, which decreases baby's pain. But it's been shown in the research that probiotics don't change the infant gut microbiome.

There is also no evidence, and no good rationale, to link the highly variable gut microbiome of our babies, even our crying babies, with physical experiences of pain. When baby's sympathetic nervous system is frequently dialled up high, this has an impact on the gut microbiome composition, but there is still no scientific reason to think of this as causing pain.

Importantly, research studies in this field do continue to have big blind spots about the impact of breastfeeding challenges on baby crying and fussing. I think this blind spot in the research means that we have to take these findings about probiotic use in fussy breastfed babies with a grain of salt, and not especially rely upon it.

Research looking at probiotic use in fussy breastfed babies doesn't take into account the effects of lactose overload

This is because none of the studies investigating probiotic use in crying breastfed babies have taken into account the possibility of lactose overload, a breastfeeding problem which really does cause inflammation of the large gut and pain in babies. It is possible that this inflammation may downregulate somewhat in response to baby taking Lactobacillus reuteri.

But what really matters when you have an unsettled breastfed baby is that you have help to directly deal with any cause of lactose overload in your baby, as well as all the other underlying problems that can make babies cry and fuss a lot.

You can find out about lactose overload here.

Currently, it seems sensible to try Lactobacillus reuteri if your breastfed baby is fussing a lot, given the research. But to my mind you'll be best able to dial your baby down and make the days and nights most manageable if you are able to deal with the actual underlying problems which cause breastfed babies to dial up a lot, discussed in here in Possums Breastfeeding & Lactation.

Research shows that biotics don't improve baby sleep

A systematic review has found that biotics, which include probiotics in over half the studies but also prebiotic and synbiotic supplementation, don't improve sleep durations in babies in the first year of life.

Selected references

Matin M, Brockway M, Badejo A. Effect of biotic supplementation on infant sleep and setting behaviours: a systematic review and meta-analysis. Beneficial Microbes. 2024:https://doi.org/10.1163/18762891-bja18700034.

Quin C, Estaki M, Vollman DM, Barnett JA, Gill SK, Gibson DL. Probiotic supplementation and associated infant gut microbiome and health: a cuationary retrospective clinical comparison. Scientific Reports. 2018;8:8283.

Vaz SR, Tofoli MH, Avelino MAG, Da Costa PSS. Probiotics for infantile colic: is there evidence beyond doubt? A meta-analysis and systeamtic review. Acta Paediatrica. 2023;113:170-182.