Randomised controlled trial of the effects of L-ornithine on stress markers and sleep quality in healthy workers
1 Research Laboratories for Health Science & Food technologies, Research & Development Division, Kirin Co., Ltd., 1-13-5, Fukuura, Kanazawa-ku, Yokohama, Kanagawa 236-0004, Japan
2 Healthcare Products Development Center, Kyowa Hakko Bio Co., Ltd., 2, Miyukigaoka, Tsukuba, Ibaraki, 305–0841, Japan
3 Cognitive and molecular of Brain disease, Kurume University, 67, Asahi-machi, Kurume, Fukuoka 830-0011, Japan
4 Department of Psychology, Kurume University, 1635, Miimachi, Kurume, Fukuoka 839-8502, Japan
Nutrition Journal 2014, 13:53 doi:10.1186/1475-2891-13-53Published: 3 June 2014
L-ornithine is a non-essential, non-protein amino acid. Although L-ornithine is contained in various foods, the amount is usually small.
Recently, studies have shown that orally administered L-ornithine reduced the stress response in animals.
From these findings, we speculated that L-ornithine may play a role in the relieve of stress and improve sleep and fatigue symptoms in humans. Through a randomised, double-blind, placebo-controlled clinical study, we asked if L-ornithine could be beneficial to stress and sleep in healthy workers.
Fifty-two apparently healthy Japanese adults who had previously felt slight stress as well as fatigue were recruited to be study participants and were randomly divided into either the L-ornithine (400 mg/day) or placebo group. They orally consumed the respective test substance every day for 8 weeks. Serum was collected for the assessment of cortisol and dehydroepiandrosterone-sulphate (DHEA-S). Perceived mood and quality of sleep were measured by the Profile of Mood States (POMS), Athens Insomnia Scale (AIS), and Ogri-Shirakawa-Azumi sleep inventory MA version (OSA-MA).
Serum cortisol levels and the cortisol/DHEA-S ratio were significantly decreased in the L-ornithine group in comparison with the placebo group. Also, anger was reduced and perceived sleep quality was improved in the L-ornithine group.
L-ornithine supplementation has the potential to relieve stress and improve sleep quality related to fatigue, both objectively and subjectively.