Human milk oligosaccharides (HMOs) have been shown to contribute to a healthy gut and immune system, as well as provide a barrier to gut infections. HMOs are also believed to promote healthy brain development. Research found that premature infants fed human milk perform better on developmental tests and have higher intelligence quotients than formula fed infants.1,2 A body of evidence suggests that brain development and cognition may partially depend on sialic acid. HMOs in mother’s milk are a rich source of sialic acid and may provide babies with a supplementary source of sialic acid as an essential nutrient for brain development and cognition. One study showed that sialic acid concentrations were significantly higher in the brains of breast-fed infants compared to infants fed formula (which contains significantly lower amounts of sialic than human milk). 3 One study proposed that when “good” gut bacteria feed on HMOs, the sialic acid is released from the HMOs structure.4 It remains to be investigated whether the released sialic acids from HMOs are actually a nutrient for infants’ brain development and if they contribute to superior developmental scores and intelligence quotients in breast-fed infants.