Astaxanthin (3,3′-dihydroxy-β, β′-carotene-4,4′-dione) is a liposoluble carotenoid usually ingested through the supplementation of Haematococcus pluvialis-derived antioxidant products. Based upon research conducted in mice, astaxanthin supplementation can improve indices of exercise recovery, metabolism and performance due to its potent antioxidant capacity. In exercising humans, similar observations have yet to be consistently realised. The following investigations were conducted to further explore the effect of astaxanthin supplementation on exercise recovery, substrate utilisation and endurance performance in recreationally active and trained human males. As a potent antioxidant compound, astaxanthin is suggested to provide a recovery benefit through the inhibition of pro-oxidant and pro-inflammatory intermediates post-exercise. This ability was investigated in Study 1 using a 30 min downhill run to induce muscle damage. In comparison to the placebo, indices of muscle damage and recovery post-exercise were not influenced by the prior eight-week intake of astaxanthin. Additionally, the lipophilic properties of astaxanthin allow it to protect and upregulate key metabolic enzymes involved in fat oxidation. Study 2 therefore utilised a graded exercise protocol to investigate whether four or eight weeks of astaxanthin supplementation could enhance the fat oxidative capacity during exercise. Again, no differences were reported when compared to the placebo. Astaxanthin has, however, been reported to peak in human plasma within the first week of intake. Study 3 was therefore the first to investigate and report an ergogenic and metabolic effect of astaxanthin following a shorter seven-day supplementation period, with improvements in performance and whole-body fat oxidation reported during a 40 km cycling time trial. Collectively, these studies highlight the importance of developing an optimal dosing strategy for astaxanthin intake based upon human pharmacokinetic data. With this knowledge, further explorations into the efficacy of astaxanthin in exercising humans can be made while using a supplementation strategy that has been developed from scientifically rigorous, evidence-based practice.
|Date of Award||11 Dec 2019|
|Supervisor||LARS MCNAUGHTON (Director of Studies) & Andy Sparks (Supervisor)|