What is Astaxanthin?
Astaxanthin. It may be a mouthful to say, but recently this compound has had increasing interest in the health and nutrition world. Found in algae, salmon, krill, trout, shrimp and some other crustaceans, astaxanthin is a pigment and is responsible for the characteristic red/pink colour of these plants and creatures. It is part of a group of compounds called carotenoids which are commonly found in bright coloured fruits and vegetables such as carrots, apricots and tomatoes to name a few. Astaxanthin possesses strong antioxidant properties similar to that of other carotenoids such as beta-carotene and lycopene. In fact, some studies have shown astaxanthin to have 40-1000 times stronger anti-oxidative capacity as that of carotenoids and vitamin E.
Uses of Astaxanthin
Astaxanthin is most commonly used as an additive due to it strong pigmenting properties. As such, it is commonly used in animal feeds as a way of imparting colour onto farm raised salmon and egg yolks. In addition, it is also used as a natural food colorant. Recently however, astaxanthin has been incorporated into dietary supplements due to strong evidence to suggest it as a potent antioxidant capable of helping with a variety of conditions including: sore muscles and joints, back pain, osteoarthritis, cholesterol levels, prostate health, menstrual cramps, cardiovascular health and sunburn to name a few.1
There are two ways to source astaxanthin; through synthetic means or through natural collection from animal and plant sources. Synthetic astaxanthin fetches around $2000/kg however, is considered of lower quality due to the presence of stereoisomers. That is, chemically speaking the product is astaxanthin, however differs structurally, which may affect its function. Naturally derived astaxanthin is the preferred compound to be used and as such fetches around $7000/kg. Astaxanthin supplements generally come in capsule form and can be supplied through either krill oil or through algal meal, harvested from microalgae. It is important to note that algae contains the highest levels of astaxanthins relative to its weight and can be harvested more sustainably than krill.
Astaxanthin in Sports Nutrition
Besides helping with the conditions discussed above, astaxanthin has also created interest in the sports nutrition world due to its implication in several studies to act as an ergogenic supplement. In a recent animal study by Aoi et al (2008)2, mice were split into control and exercise groups with each group also being split into control and astaxanthin groups. Each astaxanthin group was given astaxanthin at an amount equal to 0.02% of their total body weight. Aoi was able to find that mice treated with astaxanthin exhibited three ergogenic qualities:
- Respiratory Exchange Ratio Shifts – During exercise, the mice that supplemented with astaxanthin had lower respiratory exchange ratios. That is, they appeared to be using more fat as a fuel source than the control groups.
- Decreased Glycogen Use – After exercise, muscle biopsies revealed that muscle glycogen stores were greater in mice supplemented with astaxanthin than controls. Greater glycogen left over could mean a) a decreased dependence on carbohydrates as a fuel and b) longer time to fatigue.
- Improved Carnitine Palmitoyltransferase (CPT 1) Activity – CPT 1 is an essential transporter of fats into the mitochondria to be used as fuel. Aoi hypothesised that oxidation from reactive oxygen species produced during exercise decreased the functionality of CPT 1 and that the strong antioxidant properties of astaxanthin would help. Indeed, those mice supplemented with astaxanthin had less oxidation affected CPT 1. This mechanism could be an explanation for the first two ergogenic qualities seen.
Another animal study by Ikeuchi et al (2006)3 examined three concentrations of astaxanthin supplementation on mice (1.2, 6 or 30mg/kg body weight). The study was able to show that fat utilisation during exercise was increased with astaxanthin supplementation as well as an increased time to exhaustion in a swimming exercise. A follow on experiment by Ikeuchi et al (2007)4 looked at astaxanthin and its effect on body composition in mice. Ikeuchi again used the same three different concentrations of astaxanthin and found that mice fed a high fat diet had reduced body weight gain at astaxanthin doses of 6 and 30mg/kg body weight. Adipose or fat tissue in the mice was also lower in all mice treated with astaxanthin, however was only significant in mice receiving the highest dose.
Astaxanthin & Sports Performance
Unfortunately, very few human studies have been performed looking at astaxanthin on sports performance. Three studies found include an unpublished Swedish study, a Japanese study and an American study. The Swedish study5 possessed a fairly bad experimental protocol, which accounted for its unpublished status. However, preliminary results from the study found that supplementation with an astaxanthin capsule with an unspecified astaxanthin concentration over an unspecified period of time led to significantly improved endurance with a squat protocol. Sawaki et al (2002)6 performed two studies involving astaxanthin on 34 healthy university age males. The study examined astaxanthins ability to affect visual acuity and lactic acid production during a 1200 metre run. Overall the study was able to show three strong associations with a daily 6mg dose of astaxanthin:
- Improved Depth Perception – Depth perception is critically important for several sports. An improved depth capacity means being able to more accurately servery the world in three dimensions and also to judge distance. For example, judging the distance between the ball and a racquet or a bat to accurately hit the ball.
- Decreased Critical Flicker Fusion Threshold – The critical flicker fusion threshold is a common visual test for the degree of central fatigue or fatigue related to the central nervous system.
- Decreased Lactic Acid – Muscle biopsies showed a decreased amount of lactic acid in subjects supplementing with astaxanthin. Lactic acid was previously considered a main cause of muscular fatigue; however, thorough research has proven otherwise. Whether or not the decreased lactic acid levels shown with astaxanthin supplementation provided any ergogenic effects is still inconclusive.
Astaxanthin - the Super Nutrient
Astaxanthin has huge potential in becoming the latest ‘super nutrient’. So far, it has been implicated for having antioxidant, anti-inflammatory and anti-cancer properties. In addition, recent research has also shown it to have ergogenic effects including:
- Reducing physical fatigue
- Increasing fat utilisation
- Improving body composition
- Improving depth perception
- Decreasing visual fatigue
As with all supplements however, it is important to remember that they are there as a complement to a healthy and well rounded lifestyle of proper nutrition and exercise, and not as a substitution. In terms of dose, it is hard to define a therapeutic dose that could offer the proposed benefits listed above; however, translating the doses used in the above studies to human dosages suggests ranges of 6mg-1800mg daily. One study7 looking at the toxicity of astaxanthin found that doses of up to 465 and 557mg/kg/day of astaxanthin had no observable adverse affects on male and female rats respectively. It is important to note however that these are rough figures and it is advised to follow the dosing instructions on the supplement package if in doubt.
1 Guerin M, Huntley ME, Olaizola M. ‘Haematococcus astaxanthin: applications for human health and nutrition.’ Trends Biotechnol. 2003 May;21(5):210-6.
2 Aoi W, Naito Y, Takanami Y, Ishii T, Kawai Y, Akagiri S, Kato Y, Osawa T, Yoshikawa T. ‘Astaxanthin improves muscle lipid metabolism in exercise via inhibitory effect of oxidative CPT I modification.’ Biochem Biophys Res Commun. 2008 Feb 22;366(4):892-7. Epub 2007 Dec 17.
3 Ikeuchi M, Koyama T, Takahashi J, Yazawa K. ‘Effects of astaxanthin supplementation on exercise-induced fatigue in mice.’ Biol Pharm Bull. 2006 Oct;29(10):2106-10.
4 Ikeuchi M, Koyama T, Takahashi J, Yazawa K. ‘Effects of astaxanthin in obese mice fed a high-fat diet.’ Biosci Biotechnol Biochem. 2007 Apr;71(4):893-9. Epub 2007 Apr 7.
5 Malmsten CL. ‘Dietary supplementation with astaxanthin-rich algal meal improves muscle endurance – a double blind study on male students.’ http://www.cyanotech.com/pdfs/bioastin/batl28.pdf. Last Accessed 3rd August 2011.
6 Sawaki, K. et al. (2002) Sports performance benefits from taking natural astaxanthin characterized by visual activity and muscle fatigue improvements in humans. J. Clin. Ther. Med., 18(9):73-88
7 Stewart JS, Lignell A, Pettersson A, Elfving E, Soni MG. ‘Safety assessment of astaxanthin-rich microalgae biomass: Acute and subchronic toxicity studies in rats.’ Food Chem Toxicol. 2008 Sep;46(9):3030-6. Epub 2008 Jun 10.