Selenium is a trace element that is an essential micronutrient for human health. Selenium is essential for many biological processes including thyroid hormone metabolism and the body’s response to oxidative stress. There has been recent research highlighting the protective role of selenium for cardiac health. 

The authors of a recently published review article describe the current understanding of the relationship between selenium and cardiovascular function. Selenium has been shown to support cardiac function through its role in redox regulation, calcium homeostasis, and certain enzymatic functions. Proteins with selenium attached are called selenoproteins, which have also been shown to play a role in cardiac health. 

Deficiencies in selenium have been linked to cardiac-related pathologies. Two recent cases of cardiomyopathies were related to conditions due to selenium deficiencies and were shown to be reversed by treatment with selenium. Low serum selenium concentrations have been associated with certain cases of heart failure. Some studies have shown that 50% of individuals with heart failure express micronutrient insufficiencies or other forms of malnutrition. Low selenium levels have been associated with higher rates of all-cause mortality due to cardiomyopathy, heart failure, and increased rates of myocardial infarction.

Selenium modulates thyroid hormone metabolism, synthesis, and activation. It is a component of the enzyme thyroxine 5-deiodinase, which helps transform thyroid hormones into their active form. Thyroid hormone dysregulation has been associated with cardiac pathologies, which included aberrant cardiac contractility, cardiac hypertrophy, and altered myocardial development. 

Selenium may also help support cardiac function in the presence of oxidative stress. Selenium is a component of enzymes including glutathione peroxidases and glutathione reductase, which helps maintain healthy levels of glutathione. Glutathione peroxidase 1 (GPX1) is a selenoprotein that is stress responsive. Selenium deficiency has been postulated to be a contributing factor to the downregulation of GPX1. In turn, this can cause a downstream effect of the heart’s diminished capacity to respond to oxidative stress and may contribute to poor cell survival. 

Thioredoxin levels may influence cardiomyocyte function. Selenoproteins, such as thioredoxin reductases, may modulate thioredoxin levels. Selenoprotein P is another molecule that may play a role in cardiac health. Decreased levels of selenoprotein P have been associated with an increased risk of mortality in the presence of acute heart failure. 

Selenium plays a critical role in many essential functions within the body. It can be obtained from dietary sources, such as dairy products, cereals, fish, yeast, eggs, certain meats, and nuts, particularly Brazil nuts. This essential trace element may support thyroid function, the body’s response to oxidative stress, the immune system, and cardiac health.

 By Colleen Ambrose, ND, MAT