Astaxanthin supplementation does not augment fat use or improve endurance performance.

INTRODUCTION: Astaxanthin is a lipid-soluble carotenoid found in a variety of aquatic organisms. Prolonged astaxanthin supplementation 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 impact of 4 wks astaxanthin supplementation 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+/-1 y, weight: 73+/-1 kg, VO2peak: 60+/-1 mL.kg.min, Wmax: 395+/-7 W) were supplemented for 4 wks with 20 mg astaxanthin per day (ASTA) or a placebo (PLA). Before and after the supplementation period, subjects performed 60 min of exercise (50% Wmax), followed by a ~1 h time trial. RESULTS: Daily astaxanthin supplementation significantly increased basal plasma astaxanthin concentrations from non-detectable values to 187+/-19 mug.kg (P<0.05). This elevation was not reflected in greater total plasma anti-oxidant 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+/-0.04 to 0.68+/-0.03 g.min and 0.66+/-0.04 to 0.61+/-0.05 g.min in the PLA and ASTA group, respectively; P=0.73). No improvements in time trial performance were observed in either group (from 236+/-9 to 239+/-7 and from 238+/-6 to 244+/-6 W in the PLA and ASTA group, respectively; P=0.63). CONCLUSIONS: Prolonged astaxanthin supplementation does not augment anti-oxidant capacity, increase fat oxidative capacity, or improve time trial performance in trained cyclists.