These sugars are known as human milk oligosaccharides—or HMOs.
Breast milk has a lot of wonderful and beneficial properties that scientists are still discovering. It contains nutrients and compounds that can protect your baby's health and boost their growth and development.
And now, according to new research, we know that breast milk contains complex sugars that not only have a hand in building a baby's microbiome, but also help them fight off infection.
These sugars, known as human milk oligosaccharides—or HMOs —"appear to provide a growth advantage for good bacteria," Steven Townsend, assistant professor of chemistry at Vanderbilt University writes in an analysis of his research into complex sugars found in human milk for The Conversation. "Breastfed babies tend to be colonized to a lesser extent by infectious species, meaning they get sick less."
That's because, Townsend continues, the microbiome in breastfed infants are abundant in two bacteria species: Bacteroides and Bifidobacteria. Both species live on humans on a daily basis, but are generally harmless. "They live in the human gut where they use human milk oligosaccharides as energy sources to grow, whereas pathogens do not," he adds.
Science already shows that these HMOs have a tremendously positive effect on an infant's health. Previous research has linked breast milk's protective properties to these complex sugars. A 2013 Nature study, for example, found that these complex sugars can cut down the length of time babies have diarrhea caused by a rotavirus infection. And researchers behind a 2005 Annual Review of Nutrition study found a link between the protective attributes of human breast milk and the HMOs contained within it.
To investigate further, Townsend and his team looked at Group B strep bacteria, which all mamas-to-be are tested for in their third trimester. Group B strep is generally harmless to healthy adults, but the bacteria can pass to the baby during childbirth, increasing their infection risk. And what they found is that HMOs acted as antibiotics against Group B strep. "In an initial study, we tried to grow Group B strep both in the presence and absence of HMOs," Townsend says. "It turned out that HMOs do prevent the growth of Group B strep bacteria."
This research is great news for women who breastfeed, but not all moms can or want to nurse. And that's something the researchers understand. Their goal moving forward, Townsend writes, is to "figure out exactly how these sugars are working and why specific women produce sugars that are more antimicrobial."
This way, he continues, researchers who have a deeper understanding of which HMOs are vital to an baby's health can synthesize the compounds so that they can be added to formula and other infant food products. Because we all know that fed is best. "A better quality infant formula that more closely mimics human breast milk may help close the health gap between breastfed and formula-fed babies," Townsend concludes.