Glutamine is an important amino acid with many functions in the body, including a special role in intestinal health. It’s a building block of protein and a critical part of the immune system. Like other amino acids, it exists in two different forms:

  • L-glutamine: The form found in foods and supplements to make protein and perform other functions. Some supplements list it as L-glutamine, but others simply use the broader term glutamine. L-glutamine can be produced naturally in your body and is the most abundant amino acid in the blood and other body fluids.
  • D-glutamine: D-glutamine appears to be relatively unimportant in living organisms.

Almost any food containing protein will contain some L-glutamine, but amounts vary. Animal foods are good sources due to their protein contents. Getting enough protein in your pet’s diet can ensure they are getting enough.