L-ornithine

 

L-ornithine L-ornithine is a non-essential, non-proteinogenic amino acid. It is produced during the body’s citric acid cycle from L-arginine. This amino acid has an important role in the urea cycle. Ornithine is required for the production of proline, glutamic acid and citrulline. These are three amino acids that assist with energy supply throughout the body.

L-ornithine for body detoxification

Ornithine plays a central role in detoxification. It helps to eliminate ammonia from the liver. Excessive levels of this toxin can lead to serious liver damage and conditions such as hepatic encephalopathy and cirrhosis. Many studies have shown that ornithine supplementation can help to reduce excessive ammonia levels1, 2, 3.

L-ornithine and muscle growth

L-ornithine together with L-arginine helps to stimulate the production of Human Growth Hormone (HGH), insulin and other growth-promoting hormones. This can help to build muscle mass. Several studies have confirmed that ornithine and arginine supplementation can be beneficial for athletes participating in resistance training programs4, 5, 6. The conversion of ornithine to arginine occurs slowly, which is why both these amino acids are usually taken together in supplements. This may help to provide continued support for people involved in body building.

L-ornithine and wound healing

L-ornithine α-ketoglutarate (a specific form of this amino acid) has been shown to help with healing wounds. This amino acid salt has been used intravenously to accelerate healing of burns7, 8, 9. L-Ornithine α-ketoglutarate is often prescribed to help reduce the time spent in hospitals for patients recovering from generalised infections, burns, cancer, surgery and other physical trauma.

L-ornithine, stress relief & insomnia

L-ornithine There is growing evidence that ornithine may help to relive stress and help people sleep better. Animal studies have found that this amino acid can reduce stress markers such as cortisol10.  More recent research has found that supplementation with l-ornithine can relieve stress and improve sleep quality in humans11.

Symptoms of l-ornithine deficiency

Ornithine deficiencies are very uncommon. Normally the body is able to produce enough of this amino acid. However, during periods of illness, stress, and malaise, ornithine and arginine levels may decline. During these periods it’s recommended to increase dietary intake of ornithine and arginine rich foods.

Dietary sources of l-ornithine

Meat, fish, dairy products, nuts, soya, rice, and wheat are good sources of ornithine. This amino acid is often present in dietary supplements and ideally should be taken together with other key amino acids. As with any supplement, it is important to check with a medical practitioner to determine suitability prior to taking the product.

Summary

L-ornithine is a non-proteinogenic amino acid that is produced by the body. It is important for detoxification and indirectly supports muscle growth. This amino acid can also assist with wound healing and combat stress and fatigue. Ornithine is found in many foods and can also be taken in supplement form. Deficiencies in this amino acid are very rare.

References

  1. Kircheis G, et al (1997). Therapeutic efficacy of L-ornithine-L-aspartate infusions in patients with cirrhosis and hepatic encephalopathy: results of a placebo-controlled, double-blind study . Hepatology. Volume 25, Issue 6, (pp. 1351-60)”
  2. “Ahmad I, et al (2008). L-ornithine-L-aspartate infusion efficacy in hepatic encephalopathy . J Coll Physicians Surg Pak. Volume 18, Issue 11. (pp. 684-7).”
  3. “Stauch S, et al (1998). Oral L-ornithine-L-aspartate therapy of chronic hepatic encephalopathy: results of a placebo-controlled double-blind study. J Hepatol. Volume 28, Issue 5, (pp. 856-64).”
  4. “Demura, et al. (2010). The effect of L-ornithine hydrochloride ingestion on human growth hormone secretion after strength training. Advances In Bioscience and Biotechnology. Volume 1, Issue 1, (pp.  7-11).”
  5. “Chromiak, J and Jose A. (2002). Use of amino acids as growth hormone-releasing agents by athletes. Nutrition. Volume 18, Issue 7, (pp. 657-61).”
  6. “Zajac, A. et al. (2010). Arginine and ornithine supplementation increases growth hormone and insulin-like growth factor-1 serum levels after heavy-resistance exercise in strength-trained athletes. The Journal of Strength & Conditioning Research, Volume 24, Issue 4, (pp. 1082-90).”
  7. “Donati L, et al (1999). Nutritional and clinical efficacy of ornithine alpha-ketoglutarate in severe burn patients. Clin Nutr. Volume 18, Issue 5, (pp. 307-11).”
  8. “Le Bricon T, et al (1997). Ornithine alpha-ketoglutarate metabolism after enteral administration in burn patients: bolus compared with continuous infusion. Am J Clin Nutr. Volume 65, Issue 2, (512-8).
  9. “Coudray-Lucas C, et al (2000). Ornithine alpha-ketoglutarate improves wound healing in severe burn patients: a prospective randomized double-blind trial versus isonitrogenous controls. Crit Care Med. Volume 28, Issue 6, (pp. 1772-6).”
  10. Kurata K, et al (2012). Orally administered L-ornithine reduces restraint stress-induced activation of the hypothalamic-pituitary-adrenal axis in mice. Neuroscience Letters. Volume 506, (pp. 287–291).”
  11. “Miyake M, et al (2014). Randomised controlled trial of the effects of L-ornithine on stress markers and sleep quality in healthy workers. Nutrition Journal. 13:53. doi: 10.1186/1475-2891-13-53.”