Glutamine is an amino acid that plays an important role in the function of the immune system. Many athletes take glutamine to prevent upper respiratory infections and flu. It is the most abundant amino acid in the body but can be depleted during trauma, serious illness, or intense training. Glutamine is a non-essential amino acid important in protein and DNA synthesis, preservation of the immune system, acid–base balance, and fuel for the central nervous system. Masamitsu Konno and co-workers from Osaka University in Japan found that glutamine metabolism was vital for preventing colon cancer. Reduced glutamine levels trigger cancer cell growth. Glutamine supplements may promote wound healing and recovery from serious illnesses, injury, trauma, and burns. Several studies found a relationship between depressed immune function and low levels of glutamine. Good sources of glutamine include beef, chicken, fish, eggs, milk, dairy products, wheat, cabbage, beets, beans, spinach, and parsley.
(Scientific Reports 6: 38415, 2018)