Breast milk sugar promotes colitis in offspring

A sugar found in mouse breast milk promotes the generation of colitis in offspring, according to a study published online on November 22 in the Journal of Experimental Medicine .

Sugars in breast milk are essential for the development of the newborn immune system and the growth of beneficial commensal bacteria in the gut. But certain milk sugars in certain contexts could be bad news. A group led by Thierry Hennet at the University of Zurich found that newborn mice fostered by mothers lacking one particular milk sugar—sialyl(alpha2,3)lactose—were less susceptible to inflammation-induced colitis later in life. The resistance to colitis was attributed to differences in the commensal bacteria.

Determining whether this milk sugar has some redeeming qualities—for example in facilitating defense against dangerous intestinal pathogens—will require further studies.