Although Zn supplementation has been reported to reduce superoxide (O2•-) generation, lower apoptotic indices, restore ATP levels and attenuate NADPH oxidase mediated oxidative stress [2,[11], [12], [13], [14]], there is evidence that Zn supplementation at the onset of reperfusion enhances the severity of myocardial infarction (MI) [15] and increases reactive oxygen species (ROS) generation in cardiomyocytes and aortic smooth muscle cells [[16], [17], [18]]. This evidence concerns the gene FMO5 and myocardial infarction.