3'‑GL is a trisaccharide of D-galactose linked with lactose (Gal β1‑3 Gal β1‑4 Glc). It is present in low concentrations (0.039 g/l) in colostrum and rapidly declines over lactation. It is not yet established to what degree significant 3'‑GL concentrations are present in human milk after the first month of lactation (Newburg et al. 2016). Therefore, little is known about its potential health effects (He et al. 2014; Newburg et al. 2016).