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

• Published in: Nutrition research (New York, N.Y.) N.Y.), 2013-07, Vol.33 (7), p.557-564
• Main Authors: Horiuchi, Masahisa, Kanesada, Hirohiko, Miyata, Takahiro, Watanabe, Kentaro, Nishimura, Akihito, Kokubo, Takashi, Kirisako, Takayoshi
• Format: Article
• Language: English
• Subjects: Adult; Ammonia - blood; Antarctic Regions; Biological and medical sciences; Branched-chain amino acids; Creatine kinase; Creatine Kinase - blood; Disorders of higher nervous function. Focal brain diseases. Central vestibular syndrome and deafness. Brain stem syndromes; Double-Blind Method; Endocrinopathies; Energy balance; Expeditions; Feeding. Feeding behavior; Fundamental and applied biological sciences. Psychology; Gastroenterology and Hepatology; Humans; Japan; Japanese Antarctica expedition members; L-Lactate Dehydrogenase - blood; Medical sciences; Nervous system (semeiology, syndromes); Neurology; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Ornithine - pharmacology; Ornithine - therapeutic use; Seasons; Serotonin metabolism; Sleep - drug effects; Sleep disturbances; Sleep Wake Disorders - blood; Sleep Wake Disorders - prevention & control; Surveys and Questionnaires; T3 polar syndrome; Thyroid. Thyroid axis (diseases); Tryptophan - blood; Vertebrates: anatomy and physiology, studies on body, several organs or systems
• ISSN: 0271-5317; 1879-0739
• DOI: 10.1016/j.nutres.2013.05.001

Abstract 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.