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Retinal risks of high-dose ornithine supplements: a review
Seiji Hayasaka1, Tatsuo Kodama, Akihiro Ohira
1Hayasaka Eye Clinic, 3-36-1 Unosato, Sakura, Tochigi 329-1323, Japan.
The British Journal of Nutrition
|July 20, 2011
Summary
Ornithine supplementation is beneficial for ammonia detoxification but high doses may cause retinal toxicity. Long-term, high-dose ornithine intake is risky for the retina, especially for patients with gyrate atrophy.
Area of Science:
- Biochemistry
- Ophthalmology
- Nutritional Science
Background:
- Ornithine supplementation is recognized for its utility by nutritionists and physicians.
- Paediatricians and biochemists utilize ornithine for ammonia detoxification in hyperornithinaemia-hyperammonaemia-homocitrullinuria (HHH) syndrome.
- Ophthalmic research indicates potential retinotoxicity with high-dose ornithine.
Purpose of the Study:
- To review the literature on ornithine supplementation, focusing on its benefits and risks.
- To evaluate the safety of ornithine intake concerning retinal health.
- To provide guidance on ornithine supplementation for specific patient populations.
Main Methods:
- Literature review of studies on ornithine supplementation.
- Analysis of in vivo and in vitro experimental data on ornithine toxicity.
- Examination of clinical observations regarding ornithine levels and retinal conditions.
Main Results:
- High concentrations of ornithine or its metabolites can be toxic to retinal pigment epithelial (RPE) cells.
- Long-term, high-dose ornithine intake (exceeding 600 μmol/l) is linked to retinal toxicity in gyrate atrophy (GA).
- Intermittent high levels, constant levels between 250-600 μmol/l, or levels below 250 μmol/l do not induce significant retinal lesions.
Conclusions:
- Short-term, low-dose, or transient high-dose ornithine intake appears safe for the retina.
- The nutritional benefits and ammonia detoxification effects of ornithine are supported but may be limited.
- Long-term, high-dose ornithine intake poses risks to the retina; caution is advised for patients with GA, HHH syndrome, heterozygotes of GA, and those with RPE lesions.
