Physical Endurance and Muscle Recovery
Work, Sport, Leisure – in fact all physical activity will generate reactive oxygen species (ROS); the more intense the activity the greater number of free radicals. ROS are shown to have damaging effects on muscle performance and recovery. Published and on-going research, focused on improving endurance and reducing recovery time, are showing dramatic benefits linked to the potent carotenoid – astaxanthin. These findings are bringing astaxanthin to the forefront as a dietary supplement for professional athletes and physically active people.
Astaxanthin Boosts Endurance
In a randomized, double-blind, placebo controlled study on healthy men supplemented with 4 mg astaxanthin per day for up to 6 months at Karolinska Institute, Sweden, standardized exercise tests demonstrated that the average number of knee bends performed increased only in the astaxanthin treated group at 3 months, and by the 6 month significant improvements were observed (Figure 1) (Malmsten & Lignell, 2008).


In another study, Aoi et al., (2008) demonstrated that astaxanthin may modify muscle metabolism by its antioxidant property and result in improved muscle performance and weight loss benefits. After 4 weeks the mice running time to exhaustion had significantly improved by up to 20 % , (2002) of Juntendo University, Japan, demonstrated by using 1200 meter track athletes, that a daily dose of 6 mg per day for 4 weeks resulted in their bodies accumulating lower levels of lactic acid (Figure 3). Ikeuchi et al., (2006) also reported the same findings and furthermore, astaxanthin efficacy had a dose-dependent response (Figure 4).


In a double blind controlled placebo study, healthy women (n= 32; age-23-60) who ingested 12 mg of astaxanthin for 6 weeks significantly reduced their body fat (4%) when conducting routine walking exercise, compared to a placebo group. In addition, while control group increased their lactic acid by 31% compared to the astaxanthin group – only 13%
The Mechanism
The mechanism behind muscle endurance is based on several findings. Generally, astaxanthin protected the skeletal muscle from the increased damage of oxidative stress generated by physical activity. Furthermore, astaxanthin increased the metabolism of lipids as the main source of energy production by protecting the carnitine palmitoyltransferase I (CPT I) involved in fatty acid transport into mitochondria. Aoi et al., (2003) of Kyoto Prefecture University used mice models that may partially explain the efficacy of astaxanthin; they compared control, exercise placebo, and astaxanthin treated exercise groups after intense physical activity. 4-hydroxy-2-nonenal-modified-protein (4-HNE) stain analyses of the calf (gastrocnemius) muscles revealed significantly lower peroxidation damage (Figure 5).

Other biochemical markers for oxidative damage and inflammation such as DNA, (2003) also explained that astaxanthin directly modulates inflammation caused by the release of the pro-inflammatory cytokines and mediators. In vivo and in vitro tests demonstrate that astaxanthin inhibits the IκB Kinase (IKK) dependant activation of the Nuclear Factor-kB (NF-κB) pathway, a key step in the production of pro-inflammatory cytokines and mediators. Aoi et al., 2008 also demonstrated increased lipid metabolism compared to carbohydrate as the main source of energy during strenuous activity (Figure 6). Furthermore, analysis of the mitochondrial lipid transport enzyme known as carnitine palmitoyltransferase I (CPT I) revealed increased fat localization (Figure 7) and reduction of oxidative damage in the presence of astaxanthin (Figure 8). CPT I is important because it regulates fatty acyl-CoA entry into the mitochondria in the oxidation of fatty acids in muscle. Exercise-induced ROS may partly limit utilization of fatty acid via diminishing CPT I activity.

Calculated from the respiratory exchange ratio (RER) and oxygen consumption. Values are means ± SE obtained from 8 mice.


Outlook
Strenuous physical activity generates high levels of ROS which affect muscle performance and metabolism of lipids. New research shows that astaxanthin can modify muscle metabolism via its antioxidant effect, resulting in the improvement of muscle function during exercise. Therefore, astaxanthin is expected to be useful for physically active people as well as athletes.
References
- Aoi W, Naito Y, Sakuma K, Kuchide M, Tokuda H, Maoka T, Toyokuni S, Oka S, Yasuhara M, Yoshikawa T. (2003). Astaxanthin limits exercise-induced skeletal and cardiac muscle damage in mice. Antioxid Redox Signal, 5(1):139-144.
- Aoi W, Naito Y, Takanami Y, Ishii T, Kawai Y, Akagiri S, Kato Y, Osawa T, Yoshikawa T. (2008). Astaxanthin improves muscle lipid metabolism in exercise via inhibitory effect of oxidative CPT I modification. Biochem. Biophys. Res. Com., 366:892–897.
- Fukamauchi, M. (2007). Food Functionality of astaxanthin-10: Synergistic effects of astaxanthin-10 intake and aerobic exercise. Food Style 21, 11(10). [In Japanese]
- Ikeuchi M, Koyama T, Takahashi J, Yazawa K. (2006). Effects of astaxanthin supplementation on exercise-induced fatigue in mice. Bio. Pharm. Bull., 29(10):2106-2110.
- Lee SJ, Bai SK, Lee KS, Namkoong S, Na HJ, Ha KS, Han JA, Yim SV, Chang K, Kwon YG, Lee SK, Kim YM. (2003). Astaxanthin Inhibits Nitric Oxide Production and Inflammatory Gene Expression by Suppressing IκB Kinase-dependent NF-κB Activation. Mol. Cells, 16(1):97-105.
- Malmsten C, Lignell A. (2008). Dietary supplementation with astaxanthin rich algal meal improves muscle endurance – a double blind study on male students. Carotenoid Science 13:20-22.
- Sawaki K, Yoshigi H, Aoki K, Koikawa N, Azumane A, Kaneko K, Yamaguchi M. (2002). Sports performance benefits from taking natural astaxanthin characterized by visual activity and muscle fatigue improvements in humans. J Clin.Therap. Med., 18(9):73- 88.
President of Corporate Fuji Chemical Industry Co., Ltd.
Croatian Center of Renewable Energy Sources (CCRES)