“The effect of AS on mental status can be extended to brain function-related symptoms, such as depression,” wrote the researchers in MDPI’s Nutrients journal.
These results could be welcomed news to the dietary supplements industry as the global astaxanthin market is projected to hit $2.57bn by 2025, growing at a CAGR of 18.9%, fueled by increased consumer demand and awareness of products promoting anti-aging and mental health benefits, according to Grand View Research.
Astaxanthin, a red oceanic carotenoid found in shellfish, fish, and algae, and sesamin (sesame seed extract), have both been linked to antioxidative activities separately but have never been studied in combination for their anti-fatigue effect, according to researchers.
"Given the unique structure of astaxanthin with its polar ends and aliphatic chain linking them, as well as its remarkable potency as a free radical scavenger, astaxanthin is well suited for managing free radical damage to phospholipids," Dr. Mark Miller, principal of Kaiviti Consulting, LLC, told NutraIngredients-USA.
The study's outcomes could also be encouraging to city dwellers living busy daily lives, Miller added.
"This Japanese study bears the hallmarks of a modern urban lifestyle. The combination of mental stress and a short physical burst of exercise results in a well-defined feeling of fatigue. Commuters must be familiar with the feeling, and also encouraged with the results of this potential treatment," Miller said.
"Urban fatigue, a not too uncommon affliction, may now be managed with a dietary intervention."
Fujifilm Co. of Tokyo, Japan, supported the study financially.
The study, performed in a randomized, double-blind, placebo-controlled, two-way crossover design, recruited 24 healthy adults between the ages of 30 and 60 who were divided into two groups of 12.
Soft gel capsules, containing 3 mg of astaxanthin derived from Haematococcus pluvialis (ASTOTS, Fujifilm) and 5 mg of sesamin derived from Sesamum indicum L., were given as supplements to participants. Placebo capsules were identical to AS in shape, color, and taste.
On test days, subjects took two capsules between breakfast and either mental or physical tasks followed by a four-hour recovery period.
On the mental task day, participants completed four hours of visual display terminal (VDT)-based mental exercises including four sets of 30-minute simple working memory tests and four 30-minute sets of selective attention and spatial working memory tasks.
For fatigue-inducing physical tasks, participants spent four hours on an ergometer bicycle at 80% of their target heart rate on the second screening day and second clinic visit day.
Outcomes were measured based on the participants’ subjective feelings, work efficiency, autonomic nerve activity, and levels of PCOOH (plasma phosphatidylcholine hydroperoxide), an oxidative stress marker.
Results indicated that the subjective fatigue score increased four hours after the mental task, then decreased throughout the recovery period after both AS and placebo supplementation.
However, “Participants recovered more promptly from VDT-induced mental fatigue after four weeks of AS supplementation than after placebo supplementation.”
"An interesting aspect was that the authors showed that this combination of mental and physical stress resulted in an oxidative stress response, as demonstrated by an increase in phospholipid peroxides," Miller commented.
"The astaxanthin + sesamin treatment lowered this oxidative stress but the magnitude was small; one ponders if this reflects the low dose of astaxanthin. Nevertheless, at these doses the benefits were more apparent on perceived fatigue than on the biochemical markers of oxidative stress."
The effect of AS supplementation on physical fatigue was not conclusive, as a carry-over effect was observed due to mental and physical tasks being performed on two consecutive days.
“Further investigation is needed to assess the anti-fatigue effect of AS on physical fatigue.”
Additionally, PCOOH was not measured separately after each mental and physical task and only continuous ingestion of AS was evaluated in this study.
“It is not possible to determine whether the observed effects were due to continuous ingestion or a single ingestion,” researchers added.
2018, 10(3), 281; doi:10.3390/nu10030281
“Effects of dietary supplementation of astaxanthin and sesamin on daily fatigue: a randomized, double-blind, placebo-controlled, two-way crossover study”
Authors: A. Imai, et al.