Oligosaccharides of Nonhuman Milk Origin

As HMOS are resistant to digestion, they reach the colon unchanged, where they can develop their prebiotic effect. Finally, they can be detected in the feces as well as in the urine of breastfed infants (21). 

Apart from their prebiotic effects, there is also evidence that HMOS act as receptor analogues to inhibit the adhesion of pathogens on the epithelial surface (22) and interact directly with human immune cells (23) as well as with animal immune cells in preclinical experiments (24,25). 

The development of new analytical techniques has significantly improved our knowledge about the structures of HMOS (26-28). Additionally, new preparation methods have been developed that allow purification of ohgosaccharide structures, which is a prerequisite for identifying their biological effects (29,30). 

However, there are still many questions remaining regarding the relationship between the structure of oligosaccharides and their biological function. For the future, it would be important to know which structural elements in HMOS play the key role for their function. 

As the structure of HMOS is so complex, there is so far no possibihty of producing identical structures for production of infant formulas [structural aspects of HMOS were intensively reviewed by Boehm and Stahl (15)]. 

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