Glutamic acid
Glutamate is also a neurotransmitter (see below), which makes it one of the most abundant molecules in the brain. Malignant brain tumors known as glioma or glioblastoma exploit this phenomenon by using glutamate as an energy source, especially when these tumors become more dependent on glutamate due to mutations in the gene "IDH1".
Sialic acid
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.