Provided is a raw material for a food additive which promotes the intracerebral release of monoamines such as dopamine and noradrenaline, and imparts a function to prevent cranial nerve disease and a function to improve brain function to foods, by being added to said foods. This method involves using as a food additive an oligopeptide mixture containing dipeptides or tripeptides having tyrosine or phenylalanine as constituent amino acids, in order to produce foods to prevent cranial nerve disease or foods to improve brain function.
