Selenium yeast is a dietary supplement that provides selenium, an essential trace mineral, in an organic form that is highly bioavailable. Scientific interest in selenium’s role in cardiovascular health is based on its antioxidant properties, primarily through selenoproteins such as glutathione peroxidases, which help reduce oxidative stress—a factor implicated in cardiovascular disease (CVD) pathogenesis. Epidemiological studies have found that low selenium status may be associated with increased risk of CVD, particularly in populations with selenium deficiency. Some randomized controlled trials (RCTs) and meta-analyses suggest that selenium supplementation, including selenium yeast, might improve certain cardiovascular risk factors such as inflammation and endothelial function. However, results are mixed and benefits appear more evident in populations with low baseline selenium levels. Large-scale trials have not consistently shown that selenium supplementation reduces major cardiovascular events or mortality in the general population. For example, the SELECT trial (which used selenium) did not find significant cardiovascular benefit. Most guidelines do not recommend selenium supplementation for CVD prevention in individuals with adequate selenium status. In summary, while there is some scientific rationale and moderate evidence for selenium yeast supporting cardiovascular health, especially in selenium-deficient individuals, robust evidence for benefit in the general population is limited.