Breastfeeding and Colic

Most colic advice gets written as if every baby feeds the same way. The strongest single piece of evidence in this space actually doesn't, and knowing that changes what's worth trying first if you're breastfeeding.

Savino and colleagues published a randomized controlled trial in Pediatrics in 2010, testing a specific probiotic strain (Lactobacillus reuteri DSM 17938) in exclusively breastfed infants with colic. The trial found a 74% reduction in daily crying time by day 21, a large effect for a single, well-tolerated intervention. This is one of the most frequently cited pieces of colic research, and for good reason, but the detail that matters most for breastfeeding parents specifically is right there in the study design: it was conducted exclusively in breastfed infants. If your baby is formula-fed or mixed-fed, this specific trial doesn't apply directly to your baby's biology; broader systematic reviews (Ellwood et al. 2020, Hjern et al. 2020) cover a wider population and are the more relevant reference there.

For breastfeeding parents specifically, two evidence-backed levers are worth knowing about, and they address different systems:

Gut microbiome: the L. reuteri DSM 17938 strain and dose used in the Savino trial. Covered fully, including why strain specificity matters, in Probiotics for Colic.

Maternal diet: a separate 2005 trial (Hill et al., Pediatrics) found a low-allergen maternal diet produced meaningful crying reduction in a majority of breastfed infants tested. Full detail in Foods That Make Colic Worse.

Both of these sit inside what this site calls the Gut Microbiome Imbalance system, one of three possible root causes. If gut isn't the primary driver for your baby, and evening-concentrated crying with clear startle-reflex triggers points more toward the nervous system, or feeding-related fussiness with excess air points toward feeding mechanics, these two levers won't be the highest-impact place to start. The root-cause guide covers all three.