Glutamine is the most abundant amino acid in the body, accounting for greater than 60% of the total intramuscular free amino acid pool. Virtually every cell in the body constantly uses glutamine for very important functions critical to life. Some tissues rely heavily on glutamine as fuel instead of glucose – immune cells and GI tract lining cells in particular. Glutamine and BCAAs help immune cells maintain their healthy functions during exercise, especially supporting upper respiratory tract health.
Glutamine is so important to your body that your body cannot afford to rely solely on dietary intake because it might run out – with dire, potentially deadly consequences. It’s that important. You need a certain amount of glutamine, or else.
Despite its foundational importance, glutamine has long been considered a “dispensable amino acid because the body has the ability to produce it. That simply means if it does not get it through the diet, the body has a mechanism to produce some glutamine from other amino acids (mostly BCAAs).
Branched-Chain Amino Acids
BCAAs are your body’s back door way to make more glutamine during times of increased need. But like glutamine, intense, long-term exercise can deplete body levels of BCAAs. BCAAs are cannibalized into making energy compounds (glucose and ketoacids) when exercise is intense, and their levels in blood decrease. BCAA supplements have been shown in human studies to maintain normal glutamine levels, especially when given during exercise, not before or after.