Journal Title (Medline/Pubmed accepted abbreviation): J. Sports Med. Phys. Fitness
Page numbers: 382-392
Summary of background and research design:
Background: Exercise increases demand for energy and, therefore, demand for oxygen and increased oxidative stress. Some oxidative stress is good, as it primes the body to be able to deal with oxidative stress and provides an overall improvement in health. However, athletes that train very intensely may experience more oxidative stress than is healthful. Supplementation with antioxidants may be beneficial in order to maximize recovery and prevent illness.
Astaxanthin is an antioxidant that red-orange in color and is found in some crustaceans (e.g., shrimp and lobster) and some algae. It has been shown in several studies to enhance sports performance.
Hypothesis: Supplementation with astaxanthin for 90 days (3 months) will lead to a decrease in exercise-induced muscle damage and oxidative stress.
Subjects: Male Serbian elite soccer players (n = 32), age about 17-19 y
Experimental design: randomized, double-blind, placebo-controlled, parallel groups
Astaxanthin- capsules containing 4 mg astaxanthin from algae/day
Placebo- capsules identical in appearance, though with sucrose (table sugar)
Protocol: All participants underwent baseline evaluation for body composition, dietary habits, maximum oxygen capacity (VO2max), and antioxidant status. They then took one of the two supplements for 90 days. After the 90 days, antioxidant enzyme activity, markers of oxidative stress, and markers of muscle damage were assessed before and after a 2 hr soccer practice. Heart rate was monitored during the practice and was used to estimate work output.
Summary of research findings:
- Average levels of TBARS (thiobarbituric acid reactive substances) and AOPP (advanced oxidation protein products), two markers of oxidative stress, did not change during the 90 day supplementation period or during the soccer exercise in either group.
- Basal levels of superoxide, a key initiator of oxidative stress, did not change with supplementation. Superoxide levels were elevated in both groups as a result of exercise, with only the placebo group reaching a statistically significant increase.
- Superoxide dismutase (SOD), an antioxidant enzyme, decreased significantly in both groups during the supplementation period with no difference between groups. Exercise did not influence the activity of SOD.
- Supplementation with astaxanthin led to a decrease in basal levels of creatine kinase (CK) and aspartate aminotransferase (AST), which are markers for muscle injury/breakdown. While these parameters increased in response to exercise, participants in the astaxanthin group experienced a smaller increase.
Key practice applications: Long-term supplementation with astaxanthin attenuated exercise-induced muscle damage during a soccer practice. Although some oxidative stress is beneficial in initiating the development of defense mechanisms, oxidative stress can be overwhelming in athletes that train intensely and/or bear other modes of stress (stress from school/work, lack of sleep, poor diet etc.). These athletes may benefit from supplementation with antioxidants.
Several follow up studies are needed before astaxanthin can be recommended to athletes. First, studies should be performed that investigate the effects of astaxanthin supplementation on sports performance. A decrease in muscle damage may lead to fewer anabolic signaling pathways being activated and therefore fewer gains. It would be interesting also if astaxanthin was investigated in regard to rate of recovery, frequency of illness, and frequency of injury. The results suggest that astaxanthin may allow faster recovery and protect from illness and overuse-based injuries.
Limitations: There were large standard deviations in some of the reported values (ex. superoxide levels in the astaxanthin group were 99 ± 94 before exercise). These large variations indicate that there were large inter-individual differences. It would have been helpful to view individual data (i.e. did the data show no pattern or did most people follow a similar trend with a few people exhibiting drastically different values?).
Sometimes it is difficult to interpret changes in antioxidant enzyme activities. For example, if an antioxidant enzyme activity is elevated, it could mean that the body has adapted to deal with elevated levels of oxidative stress. Alternatively, it could mean that the body is dealing with more oxidative stress than it can handle. Some scientists argue that it is more informative to measure damage caused by oxidative stress, such as oxidized proteins (ex. AOPP) or lipids (ex. TBARS) versus surrogate biomarkers.
Key search terms for this article (5-7 terms): astaxanthin, antioxidants, carotenoids, oxidative stress