Human milk oligosaccharides as bioactive compounds in infant formula: recent advances and trends in synthetic methods

Human milk oligosaccharides (HMO) have attracted great interest in recent years due to their role in boosting infants and adults health. According to several <i>in vitro</i>, <i>in vivo</i> and clinical studies, gastrointestinal and immune physiological systems benefit the most from HMO intake. Other organ systems, such as the respiratory, central nervous, circulatory, locomotor, and urinary systems have also been found to be affected by the HMO consumption in the recent decade. Due to their positive impact on human health, the incorporation of HMO into the infant formula or other functional foods has become highly desirable. Currently, their large-scale production is limited to 2'-fucosyllactose (2'FL) and lacto-<i>N</i>-neotetraose (LNnT) that are obtained through fermentation and added to the infant formula as fortifiers. Fewer advances have been made for other HMO to reach the industrial scale synthesis. The present paper summarizes the latest research on HMO in terms of their health benefits and synthetic methodologies, with the overall aim to establish the current status and trends in both fields.