Effects of Euglena gracilis Intake on Mood and Autonomic Activity under Mental Workload, and Subjective Sleep Quality: A Randomized, Double-Blind, Placebo-Controlled Trial

Abstract

While the human body maintains homeostasis by altering the balance in the autonomic nervous, endocrine, and immune systems, a prolonged imbalance in these systems can result in physical and mental symptoms, including a decline in sleep quality and work efficiency. Euglena gracilis (Euglena) is a single-celled microalga with the properties of both plants and animals and contains abundant nutrients, such as vitamins, minerals, amino acids, and fatty acids, which have various beneficial health effects. This study evaluated the effects of Euglena intake on the mood states and stress coping under mental workload tasks, and subjective sleep quality. We assigned men and women aged 20 to 64 years to Euglena and placebo intake groups, and measured indices related to the autonomic nervous system, psychological states, and sleep quality together with the application of workload stress before food intake, and 4, 8, and 12 weeks after commencing intake. Euglena intake regulated the autonomic nervous system under a workload and improved psychological parameters and sleep conditions. These results indicate that the consumption of Euglena may regulate the balance of the autonomic nervous system during stress and may have a favorable effect on psychological status and sleep quality.

Euglena, a Gravitactic Flagellate of Multiple Usages

“…The paramylon has also been shown to have a renoprotective effect in chronic kidney disease in a rodent [ 191 ]. Intake of E. gracilis also has positive effects on mood, autonomic activity, and sleep quality [ 192 ]. Finally, paramylon has been shown to accelerate wound healing in the skin when being applied as a film dressing [ 193 ].…”

Potential Psychoactive Effects of Microalgal Bioactive Compounds for the Case of Sleep and Mood Regulation: Opportunities and Challenges

“…Moreover, microalgal glucans exhibit antibacterial and cholesterol-lowering action and are effective in colorectal cancer treatment [ 59 ]. Recently, Nakashima et al [ 32 ] studied the effects of E. gracilis biomass on mental health and sleep in stressed and overworked individuals.…”

“…Furthermore, chronic stress is associated with depression and inflammation, and is an indicator for insomnia [ 11 , 60 ]. A 12-week clinical trial revealed that a daily dose of 500–1000 mg of Euglena had calming effects on the sympathetic nervous system and therefore promoted a more relaxed body state [ 32 ]. Similarly, the same dose of Euglena promoted mental wellbeing.…”

“…E. gracilis has the capacity to relieve anxiety, sleep difficulties and low mood [ 32 ]. However, mechanisms of action on the nervous system remain elusive.…”

Euglena gracilis-derived β-glucan paramylon entrains the peripheral circadian clocks in mice

“…Similar to other β-1,3-glucans, paramylon has a variety of health benefits, such as anti-obesity effects ( 13 ), suppression of atopic dermatitis ( 14 ), anti-HIV effect ( 15 ), and modulation of immune functions ( 16 – 19 ). Clinical trials have also shown that continuous intake of Euglena improves sleep quality ( 20 ). As it is involved in the regulation of sleep, it may be involved in clock regulation; however, no reports have been published examining whether Euglena or paramylon is involved in the regulation of the circadian clock.…”