Alpha-Lactalbumin is the main whey protein in human milk rising 2,44 g/L in 
mature milk. It has a key function in the synthesis of lactose from glucose and 
galactose in the mammary gland although this compound has also other beneficial 
effects on the infant health due to the high proportion of essential aminoacids 
(tryptophan and cysteine). It seems also to increase iron absorption in the 
digestive track, and in in vitro experiments, linked to oleic acid (HAMLET 
complex), has shown anticarcinogenic effects against cellular tumor such as 
human papilloma. In addition, this complex has been reported to exhibit 
antimicrobial properties against Streptococcus pneumoniae, Haemophilus 
influenzae, enteropathogenic strains of Escherichia coli and Salmonella 
thypimurium. However, the in vivo synthesis of HAMLET complex during milk 
digestion has not been proved yet. Infant formula have been improved 
considerably during the last decades not only adapting nutrient concentrations 
to infants requirements but also by the addition of new bioactive ingredients 
such as alpha-lactalbumin, to have the same functional effect as in breast fed 
babies.