Scientists who are investigating the functions of sialic acid are trying to determine whether sialic acid is related to fast brain growth and whether it produces advantages in brain development. It has been demonstrated that human milk contains high levels of sialic acid glycoconjugates. In fact, one study has shown that premature infants, and full-term breast-fed infants at five months of age, had more salivary sialic acid than did formula-fed infants. However human milk varies in sialic acid content, depending upon genetic inheritance, lactation, etc. Investigations are focused on comparing sialic acid’s effects upon breast-fed children versus non-breast-fed children. Brain development is complex but it occurs quickly: by two years of age, a child’s brain reaches about 80% of its adult weight. Children are born with a complete number of brain neurons, but the synaptic connections between them will be elaborated after birth. Sialic acid plays an essential role in proper brain development and cognition, and it is important that the child has an adequate supply at the time when it is needed.It has been demonstrated that the human brain has more sialic acid than the brains of other mammals (2 – 4 times more). Neural membranes have 20 times more sialic acid than other cellular membranes. It is believed that sialic acid has a decisive role in enabling neurotransmission between neurons. The effects of sialic acid supplementation on learning and memory behaviour has been studied in rodents, as well as in piglets (whose brain structure and function more closely resemble those of humans). A diet rich in sialic acid was given to newborn piglets for five weeks. Then learning and memory were evaluated using a visual cue in a maze. A relationship between dietary sialic acid supplementation and cognitive function was seen: the piglets that had been fed high doses of sialic acid learned more quickly and made fewer mistakes. This suggests that sialic acid has an influence upon brain development and learning.