Glutamine (an amino acid) is plentiful in both animal and plant protein. Dietary sources of glutamine include plant and animal proteins such as beef, pork and poultry, milk, yogurt, ricotta cheese, cottage cheese, raw spinach, parsley and cabbage. Glutamine is found in many foods high in protein, such as fish, meat, beans and dairy products. Small amounts of free l-glutamine are found in vegetable juices and fermented foods such as yogurt.
Glutamine is a nonessential amino acid and the major part of the de novo synthesis in the human body. However, during strenuous exercise, critical illness, injury or heavy stress loads, the need for glutamine can increase beyond the body’s ability to synthesise it, and therefore it becomes “conditionally essential”.