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Nutr Res. 2013 Jul;33(7):557-64. doi: 10.1016/j.nutres.2013.05.001. Epub 2013 Jun 12.

Ornithine ingestion improved sleep disturbances but was not associated with correction of blood tryptophan ratio in Japanese Antarctica expedition members during summer.

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Department of Environmental Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.


Members of expeditions to Antarctica may show changes in biological and physiological parameters involved in lipid, glucose, and thyroid hormone metabolism as they adapt to the environment; however, alterations in amino acid (AA) levels and sleep among expedition members in Antarctica have yet to be fully elucidated. We hypothesized that there would be alterations of blood AA levels, and ornithine (Orn) ingestion would affect biological parameters and sleep in Japanese expedition members during the summer in Antarctica. Japanese Antarctica Research Expedition members (22 people) who stayed in Antarctica for 3 months from December 2010 were examined, and a randomized double-blind study of Orn ingestion (400 mg/d) for 4 weeks was performed. Sleep conditions were evaluated subjectively by the Oguri-Shirakawa-Azumi (brief version) questionnaire. The blood of Japanese Antarctica Research Expedition members in Antarctica showed higher creatine kinase, lactate dehydrogenase, and ammonia levels than that in Japan. On blood AA analysis, aspartate, Orn, and serine were significantly higher, and alanine and tryptophan (Trp) were significantly lower in Antarctica than in Japan. The Trp ratio, the value of Trp divided by the sum of phenylalanine, tyrosine, and branched-chain AAs, was significantly lower in Antarctica than in Japan. Although sleep deteriorated during the stay in Antarctica, Orn ingestion, to some extent, improved sleep compared with the placebo group in Antarctica, suggesting that Orn is effective for people with heavy physical workloads in places such as Antarctica.


AA; AST; Ala; Asp; BCAAs; BMI; BUN; BW; Branched-chain amino acids; CK; ChE; Creatine kinase; Energy balance; F-T3; F-T4; GGT; Glx; JARE; Japanese Antarctica Research Expedition; Japanese Antarctica expedition members; LDH; Met; NEFA; OAT; OSA sleep inventory; Oguri-Shirakawa-Azumi sleep inventory; Orn; Pro; Ser; Serotonin metabolism; Sleep disturbances; T3 polar syndrome; TSH; Trp; alanine; amino acid; aspartate; aspartate aminotransferase; blood urea nitrogen; body mass index; body weight; branched-chain amino acids; choline esterase; creatine kinase; free-T3; free-T4; glutamine and glutamate; lactate dehydrogenase; methionine; nonesterified fatty acid; ornithine; ornithine aminotransferase; proline; serine; thyroid-stimulating hormone; tryptophan; γ-glutamyltransferase

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