Daily supplements of the amino acid ornithine may improve sleep disturbances associated with hard physical work, says new data from the Japanese Antarctica Research Expedition.
Data from 22 people indicated that ammonia levels significantly increased during the stay in the Antarctic, as skeletal muscle released more ammonia because of the severe workload. However, a daily 400 mg dose of l-ornithine hydrochloride from Kyowa Wellness for four weeks tended to reduce the increase in ammonia.
“People working in severe environments such as Antarctica show alterations in blood amino acids,” wrote Japanese researchers from Kagoshima University, the National Institute of Polar Research, and Kyowa Hakko.
“Ornithine improved sleep disturbances in people working in Antarctica, indicating that nutritional support may relieve people performing physically hard work.”
Twenty-two people who had a three month stay in the Antarctic were selected for the study. The participants were randomly assigned to receive daily ornithine supplements or placebo for four weeks.
According to results of a questionnaire, sleep deteriorated during the Antarctic stay but the ornithine supplements “improved sleep compared with the placebo group”.
Blood analysis showed that the subjects experienced increases in levels of creatine kinase, lactate dehydrogenase, and ammonia levels than they had in Japan. Blood amino acid levels for aspartate, ornithine, and serine increased, while alanine and tryptophan decreased in Antarctica, compared with Japan.
“Although sleep deteriorated during the stay in Antarctica, ornithine ingestion, to some extent, improved sleep compared with the placebo group in Antarctica, suggesting that ornithine is effective for people with heavy physical workloads in places such as Antarctica,” they concluded.
Source: Nutrition Research
Published online ahead of print, doi: 10.1016/j.nutres.2013.05.001
“Ornithine ingestion improved sleep disturbances but was not associated with correction of blood tryptophan ratio in Japanese Antarctica expedition members during summer”
Authors: M. Horiuchi, H. Kanesada, T. Miyata, K. Watanabe, A. Nishimura, T. Kokubo, T. Kirisako