Preclinical Safety Evaluation of the Human-Identical Milk Oligosaccharide Lacto-N-Triose II

Lacto-N-triose II (LNT II), an essential human milk oligosaccharide and precursor to lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT), was evaluated for safety. Genotoxicity was assessed through in vitro tests including Bacterial Reverse Mutation Test and mammalian cell micronucleus test, and a subchronic oral gavage toxicity study was conducted on juvenile Sprague-Dawley rats. In this study, LNT II was administered at dose levels of 0, 1,500, 2,500, or 5,000 mg/kg body weight (bw)/day for 90 days, followed by a 4-week treatment-free recovery period. LNT II was non-genotoxic in the in vitro assays. No compound-related effects were observed across all dosage levels based on various measures, including clinical observations, body weight gain, feed consumption, clinical pathology, organ weights, and histopathology. Consequently, the highest dosage of 5,000 mg/kg bw/day was established as the no-observed-adverse-effect-level (NOAEL). These results suggest the safe use of LNT II in young children formula and as a food ingredient, within the limits found naturally in human breast milk.