Human milk oligosaccharides … a challenge for the future
According to the Centers for Disease Control and Prevention (Atlanta, Georgia, USA), approximately 20% of all global cases of acute gastroenteritis are caused by norovirus infections. Norovirus is responsible for more than 650 million infections worldwide every year, 200,000 of which are fatal. Although norovirus causes diarrheal diseases in all age groups, it is the most common cause of diarrheal death in children up to 5 years of age. There is no vaccine against norovirus and no specific treatment for infections. However, recent studies have shown that human milk oligosaccharides (HMOs), specifically 2’-fucosyllactose and 3- fucosyllactose, may help to prevent norovirus infections by stopping the virus particles from attaching to their receptors on the cell surface. Norovirus infections begin when the virus binds to glycans expressed on the surface of mucosal epithelial cells in the digestive tract – the so-called histo-blood group antigens (HBGA). Fucosylated HMOs such as 2’-fucosyllactose, 3-fucosyllactose and more complex HMOs containing an alpha 1,2-fucose epitope are structurally similar to these HBGA receptors. This resemblance is sufficient for the HMOs to act as decoys – thus norovirus particles bind to HBGAs and HMOs in vitro in a similar manner (Weichert et al., 2016, Shang et al., 2013). More importantly, the reduced frequency of diarrhea caused by microbial infections correlates with the content of fucosylated HMOs in breast milk (Morrow et al., 2004, Yu et al., 2016).
This article is available in full in the Summer 2017 issue of Nutraceuticals Now