In vitro digestion and fermentation of lacto-N-biose, a core building block of human milk oligosaccharides

Human milk oligosaccharides (HMOs) can significantly reduce the occurrence of early food allergy in infants (by up to 50%) by improving intestinal flora. Lacto-N-biose (LNB) is a potential factor for the selective growth of Bifidobacteria. Despite these observations, little is known about whether LNB, the core component of HMOs, can alleviate infant milk allergy by improving intestinal flora. Herein, in vitro simulated digestion and fermentation of LNB and its interactions with allergic infant gut microbiota were investigated. The results showed that LNB was stable under the digestion conditions of mouth, stomach and small intestine. It also could obviously modulate the composition of gut microbiota, representing the increases of the relative abundances of Bifidobacterium (65.62%), Enterococcus (6.95%), Lactobacillus (2.01%) and Blautia (2.17%). Especially, Bifidobacterium adolescentis (5.45%) and Bifidobacterium breve (23.18%) were preponderantly existed in the milk-allergic infant intestinal flora, compared to the normal infant intestinal microbiota (P < 0.5). However, LNB treatment significantly decreased the abundance of B. adolescentis (0.18%), but largely increased the relative abundance of B. bifidum (40.63%), in comparison with the allergic infant group (8.29%) (P < 0.05). In addition, short-chain fatty acids (SCFAs), either their individuals or total productions were all increased with the treatment of LNB (195.47 mM), compared to the normal control (138.05 mM) and allergic infant groups (56.89 mM) (P < 0.05). These findings will contribute to a better understanding of the protective effects of LNB in allergic diseases and provide new insights into a potential approach to relieve infant food allergy.

Automated summary

Human milk oligosaccharides (HMOs) can reduce early food allergy in infants by improving intestinal flora. Lacto-N-biose (LNB), a component of HMOs, may alleviate infant milk allergy by modulating gut microbiota. In vitro experiments showed that LNB was stable during digestion and fermentation and had a significant impact on the composition of gut microbiota.