Astaxanthin Supplementation Does Not Augment Fat Use or Improve Endurance Performance PETER T. RES 1 , NAOMI M. CERMAK 1 , RUDI STINKENS 1 , T. J. TOLLAKSON 3 , GUIDO R. HAENEN 2 , AALT BAST 2 , and LUC J. C. VAN LOON 1 1 Department of Human Movement Sciences, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre + , Maastricht, THE NETHERLANDS; 2 Department of Toxicology, NUTRIM, Maastricht University Medical Centre + , Maastricht, THE NETHERLANDS; and 3 Des Moines, IA ABSTRACT RES, P. T., N. M. CERMAK, R. STINKENS, T. J. TOLLAKSON, G. R. HAENEN, A. BAST, and L. J. VAN LOON. Astaxanthin Supplementation Does Not Augment Fat Use or Improve Endurance Performance. Med. Sci. Sports Exerc., Vol. 45, No. 6, pp. 1158–1165, 2013. Introduction: Astaxanthin is a lipid-soluble carotenoid found in a variety of aquatic organisms. Prolonged astaxanthin supple- mentation has been reported to increase fat oxidative capacity and improve running time to exhaustion in mice. These data suggest that astaxanthin may be applied as a potent ergogenic aid in humans. Purpose: To assess the effect of 4 wk of astaxanthin supple- mentation on substrate use and subsequent time trial performance in well-trained cyclists. Methods: Using a double-blind parallel design, 32 young, well-trained male cyclists or triathletes (age = 25 T 1 yr, weight = 73 T 1 kg, V ˙ O 2peak = 60 T 1 mL j1 Ikg j1 Imin j1 , W max = 395 T 7 W; mean T SEM) were supplemented for 4 wk with 20 mg of astaxanthin per day (ASTA) or a placebo (PLA). Before and after the supplementation period, subjects performed 60 min of exercise (50% W max ), followed by an time trial of approx- imately 1 h. Results: Daily astaxanthin supplementation significantly increased basal plasma astaxanthin concentrations from non- detectable values to 187 T 19 KgIkg j1 (P G 0.05). This elevation was not reflected in greater total plasma antioxidant capacity (P = 0.90) or attenuated malondialdehyde levels (P = 0.63). Whole-body fat oxidation rates during submaximal exercise did not differ between groups and did not change over time (from 0.71 T 0.04 to 0.68 T 0.03 gImin j1 and from 0.66 T 0.04 to 0.61 T 0.05 gImin j1 in the PLA and ASTA groups, respectively; P = 0.73). No improvements in time trial performance were observed in either group (from 236 T 9 to 239 T 7 and from 238 T 6 to 244 T 6 W in the PLA and ASTA groups, respectively; P = 0.63). Conclusion: Prolonged astaxanthin supplementation does not augment antioxidant capacity, increase fat oxidative capacity, or improve time trial performance in trained cyclists. Key Words: SUBSTRATE USE, CYCLING, FAT OXIDATION, EXERCISE, ERGOGENIC AIDS, ANTI-OXIDANTS F at and carbohydrate are the two primary fuels for endurance-type exercise. However, the capacity for endurance-type exercise performance is generally lim- ited by the availability of skeletal muscle glycogen (6). As such, much research in the area of sports nutrition has been directed toward improving fat oxidative capacity by dietary modulation to stimulate fat use during exercise (13,19,32). Astaxanthin has been identified as a nutritional compound that may strongly stimulate fat oxidation during exercise (4,17,33). Astaxanthin is a naturally occurring lipid-soluble carotenoid, synthesized primarily by marine microalgae, with powerful antioxidant (24,25) and anti-inflammatory (2,26) properties. Astaxanthin is most known as a feed additive for farm-raised salmon, giving salmon its reddish tissue color. Using a mouse model, 4–5 wk of astaxanthin supplemen- tation (6–30 mgIkg j1 body weight) has been reported to improve fat use during exercise and subsequently increase swimming and treadmill running time to exhaustion (4,16). The observed increase in fat oxidation was suggested to be attributed to a greater capacity for fatty acyl–CoA uptake into the mitochondria via an improvement in carnitine pal- mitoyltransferase 1 (CPT1) function. Astaxanthin supple- mentation may improve CPT1 function by inhibiting the accumulation of damaging reactive oxygen species (ROS) on the mitochondrial membrane (24,25). In line with this observation, astaxanthin supplementation has been shown to attenuate the exercise-induced rise in plasma lactate and reduce muscle glycogen use (4). Taken together, these results suggest that astaxanthin may have strong ergogenic prop- erties. Research on the proposed properties of astaxanthin supplementation to modulate skeletal muscle fuel use and/or to improve performance in vivo in humans is scarce (11). Recently, Earnest et al. (11) observed no significant changes in the rate of fat oxidation during submaximal cycling ex- ercise after 4 wk of astaxanthin supplementation (4 mgId j1 ). Address for correspondence: Luc J. C. van Loon, Ph.D., Department of Human Movement Sciences, Maastricht University Medical Centre+, PO Box 616, 6200 MD Maastricht, the Netherlands; E-mail: L.vanLoon@ maastrichtuniversity.nl. Submitted for publication August 2012. Accepted for publication November 2012. 0195-9131/13/4506-1158/0 MEDICINE & SCIENCE IN SPORTS & EXERCISE Ò Copyright Ó 2013 by the American College of Sports Medicine DOI: 10.1249/MSS.0b013e31827fddc4 1158 APPLIED SCIENCES Copyright © 2013 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.