Ornithine is an amino acid derived from another amino acid called arginine, during the urea cycle. Amino acids are known for being building blocks of protein, however ornithine is not a protein constituent. Your liver produces ornithine when it converts ammonia to urea.
Your liver then transports the urea to your kidneys for excretion. An ornithine test can help evaluate liver function, due to your liver's involvement in ornithine production.
Urea Cycle
The ammonia in your body is primarily produced from protein metabolism. Your body works to remove ammonia since it is toxic even in small quantities. Your body converts ammonia to urea in order to remove it from your body. This process is called the urea cycle. Urea is a waste product in your urine that contains nitrogen. Your body produces ornithine during this process from arginine -- an amino acid needed to create urea. The urea cycle keeps ammonia from building up.
No Effect on Liver Failure
When your liver rapidly loses functionality, it is called acute liver failure. In individuals with ALF, high ammonia levels are associated with increased mortality rate and complications. Researchers at the department of gastroenterology, Institute of Medical Sciences in New Delhi, India, set out to determine what effect an ornithine infusion may have on liver function. The study, published in the June 2009 issue of the journal "Gastroenterology," found that an ornithine infusion did not lower ammonia levels or improve survival rate.
Improves Liver Cirrhosis
Liver cirrhosis is the breakdown and replacement of healthy liver tissue with scar tissue. When your liver is unable to remove toxic substances, it can cause hepatic encephalopathy -- a decline in brain function. Ornithine improves liver function and decreases ammonia in hepatic encephalopathy complicated liver cirrhosis, according to a study published in the June 2005 issue of "The Academic Journal of the First Medical College of PLA."
Supplements and Precautions
Ornithine deficiency is common if you have a liver disorder. Ornithine is available as a dietary supplement in capsule form, however, there are no studies evaluating ornithine in supplement form. Available clinical data uses ornithine infusions. Clinical data on the side effects of ornithine supplements are lacking. However, all supplements can cause side effects. It is important to consult your doctor before taking ornithine.
References
- Medical Dictionary: Ornithine
- Elmhurst College: Urea Cycle
- "Gastroenterology"; Efficacy of L-ornithine L-aspartate in Acute Liver Failure: a Double-blind, Randomized, Placebo-controlled Study; S.K Acharya; June 2009
- "The Academic Journal of the First Medical College of PLA"; Therapeutic Effect of L-ornithine-l-aspartate on Liver Cirrhosis Complicated by Hepatic Encephalopathy; M.F Chen; June 2005
