Glutamate (neurotransmitter)
Glutamate is a major constituent of a wide variety of proteins; consequently it is one of the most abundant amino acids in the human body. Under ordinary conditions enough is obtained from the diet that there is no need for any to be synthesized. Nevertheless, glutamate is formally classified as a non-essential amino acid, because it can be synthesized from alpha-Ketoglutaric acid, which is produced as part of the citric acid cycle by a series of reactions whose starting point is citrate. Glutamate cannot cross the blood-brain barrier unassisted, but it is actively transported into the nervous system by a high affinity transport system, which maintains its concentration in brain fluids at a fairly constant level.
Amino acid-based formula
Amino acid-based formula, also known as an elemental formula, is a type of hypoallergenic infant formula made from individual amino acids. Amino acids are the building blocks of protein and together they form the protein requirements in formula needed for growth and development. The amino acids are in the simplest form, making it easy for the body to process and digest. "Neocate", "EleCare" and "Nutramigen Puramino" are the more commonly encountered brands of amino acid-based formula in the US.