Glutamine
Glutamine (symbol Gln or Q) is an α-amino acid that is used in the biosynthesis of proteins. Its side chain is similar to that of glutamic acid, except the carboxylic acid group is replaced by an amide. It is classified as a charge-neutral, polar amino acid. It is non-essential and conditionally essential in humans, meaning the body can usually synthesize sufficient amounts of it, but in some instances of stress, the body's demand for glutamine increases, and glutamine must be obtained from the diet. It is encoded by the codons CAA and CAG.
Nutritional neuroscience
When protein is consumed, it is broken down into amino acids. These amino acids are used to produce many things like neurotransmitters, enzymes, hormones, and chromosomes. Proteins known as complete proteins contain all eight of the essential amino acids. Meat, cheese, eggs, and yogurt are all examples of complete proteins. Incomplete proteins contain only some of the eight essential amino acids and it is recommended that people consume a combination of these proteins. Examples of incomplete proteins include nuts, seeds, legumes, and grains. When animals are fed a diet deficient in essential amino acids, uncharged tRNAs accumulate in the anterior piriform cortex signaling diet rejection [105]. The body normally interconverts amino acids to maintain homeostasis, but muscle protein can be catabolized to release amino acids during conditions of amino acid deficiency. Disruption of amino acid metabolism can affect brain development and neurophysiology to affect behavior. For example, fetal protein deficiency decreases the number of neurons in the CA1 region of the hippocampus.