Glutamine is an essential amino acid that is critical to the production of cellular energy especially in the intestinal tract and stomach.5 The body produces it from glutamic acid. It represents 60% of the free amino acids in the body with the highest concentrations in blood plasma, muscles, and cerebral and spinal fluid. Along with cysteine and glycine it is one of the amino acid components of glutathione which is an essential antioxidant fighting free radicals and 'sticking' to heavy metals, where it has the role of removing waste and toxic materials from the body. It plays a role in many bodily functions, such as:

  • Providing an energy source for the cells1
  • Synthesizing protein.
  • Regulating the kidney's acid-base balance.2
  • Providing carbon as part of the citric acid cycle.3
  • Transporting ammonia within the blood
  • Supports immune functioning

In the diet it is found in meats and dairy products, wheat, parsley, cabbage, spinach, beans, and vegetable juices.

It is a popular addition to diets of athletes due to its energy boosting properties, and has been found to support immune functioning.4

Cataract. Glutamine residues, created as the result of deterioration of glutamine, are found in the proteins of the eye lens crystallins and in increasing amounts as we age.6 This process, called deamidation, may be responsible for the fact that the crystallins in lenses break down, the proteins clump together, and opacity increases.7

Presbyopia. The stiffness of the lens, resulting in the inability to focus on near objects, occurs as a result of the same deamidation of biochemicals such as glutamine.8

Other eye disorders. Glutamine plays an essential role in regulating the acid-base ratio in the body, with the optimal pH of between 7.35 and 7.45 to function effectively (see info on Alkaline-Acid diet.) Glutamine separates ammonia in the kidneys and protects the brain. 9

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1. Aledo, J. C. (2004). "Glutamine breakdown in rapidly dividing cells: Waste or investment?". BioEssays 26 (7): 778-785
2. Hall, John E.; Guyton, Arthur C. (2006). Textbook of medical physiology (11th ed.). St. Louis, Mo: Elsevier Saunders. p. 393
3. Yuneva, M.; Zamboni, N.; Oefner, P.; Sachidanandam, R.; Lazebnik, Y. (2007). "Deficiency in glutamine but not glucose induces MYC-dependent apoptosis in human cells". The Journal of Cell Biology 178 (1): 93-105.
4. Calder PC, Yaqoob P., Glutamine and the immune system, Amino Acids. 1999;17(3):227-41.
5. van der Hulst RR, von Meyenfeldt MF, Soeters PB, Glutamine: an essential amino acid for the gut. Nutrition. 1996 Nov-Dec;12(11-12 Suppl):S78-81.
6. Hooi, M.Y., Raftery, M.J., Truscott, R.J. (2012). Age-dependent deamidation of glutamine residues in human γS crystallin: deamidation and unstructured regions. Protein Sci, Jul;21(7):1074-9.
7. Hains, P.G., Truscott, R.J.W. (2010). Age-Dependent Deamidation of Lifelong Proteins in the Human Lens. Invest Ophthalmol Vis Sci, Jun; 51(6): 3107–3114.
8. Ibid. Hains. (2010).
9. Glutamine and glutamic acid. Retrieved Oct 30, 2017 from