Glutamine is one of the 20 most common natural amino acids on Earth. It has carboxamide as the side chains functional group.

It has been suggested glutamine is utilized at a higher than normal rate in people living with diseases that strain the immune system, such as HIV. Glutamine is used in the digestive process and a deficiency may contribute to wasting.

It is converted into the excitotoxin glutamate within neurons. Glutamine is then transported to the neuron and by the enzyme glutaminase, it is converted to glutamate--the potential excitotoxin. Unless it accumulates outside the brain cell it is harmless.

In two recent studies it was found that the amount of glutamine in the brain could predict the brain damage seen both in pediatric brain injuries and brain damage secondary to seizures. Adding large amounts of glutamine to the diet increases significantly brain levels of glutamine and, hence, glutamate. Another study found that by adding glutamine to the diet of animals exposed to another powerful excitotoxin called quinolinic acid, brain cell damage was increased significantly. Overconsumption may lead to the death of brain cells.

Glutamine accumulation has also been found in Alzheimer’s disease, Huntington’s disease and high levels of brain glutamine have been associated with a worse prognosis in Lou Gehrig’s disease. Likewise, recent studies have shown that high brain glutamine levels increase brain levels of free radicals and impair the ability of brain mitochondria to produce energy. When the brain produces low energy, excitotoxins, such as glutamate, become even more toxic. It has been shown that the reason for glutamine toxicity under these conditions is because it is converted to the excitotoxin--glutamate.

The only safe situation for glutamine use is in the vigorous athlete. Glutamine is used as a muscle fuel, so that vigorous exercise will consume most of the glutamine before it can accumulate in the brain.

de:Glutamin es:Glutamina eo:Glutamino it:Glutammina nl:Glutamine ja:グルタミン sv:Glutamin