Cardiologists at the University of Groningen in The Netherlands have published a comprehensive review of the current knowledge about selenium deficiency and the role of selenoproteins in heart failure patients [Al-Mubarak 2021].
The key points in their review are as follows:
- Selenium is an essential micronutrient. It is incorporated into 25 different selenoproteins that have many biological functions in the body.
- Suboptimal selenium intakes and status lead to the impaired cellular synthesis of these selenoproteins and to the diminished function of selenoproteins, which may aggravate oxidative stress and inflammation, both of which are associated with greater severity of heart failure.
- 70% of patients diagnosed with heart failure have suboptimal serum selenium levels (below 100 micrograms per liter).
- The heart failure patients with suboptimal serum selenium concentrations have lower exercise capacity, lower quality of life, and a worse prognosis than heart failure patients with serum selenium concentrations above 100 mcg/L.
- Clinical trials of the efficacy of selenium supplementation in patients with heart failure have shown improved clinical symptoms such as improvements in NYHA function class, in left ventricular ejection fraction, and in lipid profile.
Selenium Deficiency and Heart Failure
- Selenium deficiency has long been associated with increased incidence of Keshan disease, a form of cardiomyopathy (cardiomyopathy = disease or disorder of the heart muscle). In China, oral selenium supplementation has almost totally eliminated Keshan disease in areas where it was once endemic [Zhou 2018].
- Important selenoproteins such as the glutathione peroxidases and selenoprotein P require a sufficiently high selenium intake to reach plateau levels, generally serum selenium levels from 90 to 125 mcg/L [Hurst 2010].
- In a well-documented heart failure cohort, serum selenium levels below 100 mcg/L have been associated with reduced exercise capacity, poorer quality of life, and a worse prognosis [Bomer 2020].
- The Dutch cardiologists suggest that patients with serum selenium levels below 100 mcg/L should be considered to have suboptimal concentrations [Bomer 2020].
Observational Studies of Selenium Concentration and Heart Failure
Three meta-analyses have provided evidence of a relationship between selenium status and the risk of heart disease:
- Flores-Mateo  showed that higher selenium concentrations are associated with a reduced risk of acute coronary artery disease of 15% in pooled prospective cohort studies and a reduced risk of 57% in pooled case-control studies.
- Zhang  showed that patients with the highest level of selenium status (median 101.5 mcg/L) had a 13% lower risk of developing heart disease compared to the lowest category (median 53.7 mcg/L).
- Kuria  showed that higher selenium status reduces mortality from heart disease by 25% and incidence of heart disease by 20%, compared to low selenium status.
Studies of Selenium Supplementation – the KiSel-10 Study
The most interesting clinical study is the KiSel-10 study in which elderly community living citizens, average age 78 years, with low selenium status (mean baseline status: 67.1 mcg/L), were treated with a combination of 200 mcg of an organic high-selenium yeast preparation and 200 mg of Coenzyme Q10 daily for four years.