**9. Conclusions**

Experimental evidence suggests astaxanthin may have protective effects on cardiovascular disease when administered prior to an induced ischemia-reperfusion event. In addition, there is evidence that astaxanthin may decrease oxidative stress and inflammation which are known accompaniments of cardiovascular disease. At this stage we do not know whether astaxanthin has any therapeutic value in human cardiovascular disease either in a preventative capacity or when administered after a cardiovascular insult. It has been proposed that astaxanthin may provide cardiovascular protection through reducing oxidative stress, which is one of the nontraditional risk factors for the development of atherosclerotic cardiovascular disease. The role of oxidative stress in cardiovascular disease is supported by evidence from observational studies that have found associations between antioxidant intake, oxidative stress and cardiovascular outcomes. Despite this, clinical intervention studies using antioxidants including vitamin E, β-carotene and vitamin C, have not proved successful [22,23]. These intervention studies may have failed because of flawed design where patients were not included based on the presence of oxidative stress. Hence, many participants may not have been in a state of oxidative stress and able to benefit from antioxidant therapy. Also, in those participants where oxidative stress may have existed there was no way of assessing whether the therapy adequately corrected this. Thus, the antioxidants used such as vitamin E, βcarotene and vitamin C may not have been effective because insufficient doses were used or an inadequate length of therapy followed to correct the oxidative stress. Some antioxidants such as β-carotene may be pro-oxidant at higher doses, which could have confounded study results. 

Astaxanthin is a potent antioxidant and based on its physicochemical properties and the results of preliminary experimental studies in ischaemia-reperfusion models of cardiovascular 

disease, it warrants consideration for testing in human clinical trials. There have been no safety concerns noted so far in human clinical studies where astaxanthin has been administered. As astaxanthin is a potent antioxidant and is associated with membrane preservation, it may protect against oxidative stress and inflammation and provide cardiovascular benefits. 
