The association between the risk of heart disease and dietary intakes of selenium remains unclear. Here we report the results of some of the recent observational studies on this topic.
Risk of Cardiovascular Disease
Selenium and the Elderly
About selenium status in the elderly, not much is known. Therefore, data from the recently published Newcastle 85+ study are of interest. The researchers assessed the selenium status of 85-year-olds living in the Northeast of England. They measured serum selenium concentrations, selenoprotein P (SELENOP) concentrations, and glutathione peroxidase 3 (GPx3) activity levels [Perri 2024 Mar].
In addition, the researchers studied the relationships between each of those three biomarkers of selenium status. They observed that there was a linear relationship between serum selenium and serum SELENOP concentrations. On the other hand, they found nonlinear relationships between serum selenium levels and GPx3 activity and between serum SELENOP levels and GPx3 activity [Perri 2024 Mar].
Selenium and Good Health
Selenium is an essential trace element for good health. If we are to survive and reproduce, we need some selenium in our diets. Not much but some. The reason is that our bodies cannot synthesize the selenium we need. Many of us live in a region of the world with low selenium content in the soil and in the regionally grown food products. Accordingly, it is difficult for us to get enough selenium in our diet.
For example, Alexander et al point out that mainland Europe and Scandinavia are regions with a low intake of selenium. North America, by contrast, is a region with much higher selenium intake. There is considerable variation in the selenium content of locally cultivated food products around the world. Consequently, daily selenium intake varies considerably. Depending upon the region we live in, we may be at risk of sub-optimal selenium intakes or selenium deficiency [Alexander 2024].
Selenium and Pregnancy
Maternal selenium status declines sharply during pregnancy. In selenium-poor regions of the world, the mother’s normal everyday intake of selenium is not adequate to meet the additional needs of the fetus. In such circumstances, maternal selenium status can reach critically low levels. Meanwhile, selenium supplementation has shown positive effects on the immune system, especially in pregnancy [Schomburg 2021].
In a letter to the Deutsches Ärzteblatt International, Mücke et al urge that doctors pay extra attention to the selenium status of patients in stressful situations, e.g., pregnancy, chronic or acute illness, or convalescence. They note that there is a clear risk of selenium deficiency during pregnancy. Also after giving birth, new mothers living in selenium-poor regions will likely need selenium supplementation. They will likely need extra selenium to cope with the challenging post-partum conditions [Mücke 2021; Schomburg 2021].
Selenoprotein P Status and Colorectal Cancer Mortality
Selenium deficiency, especially as manifested in low circulating levels of selenoprotein P, is associated significantly with an increased risk of colorectal cancer incidence and mortality [Pal 2024; Brezina 2025]. SELENOP is a selenium-dependent glycoprotein that is the primary transporter of selenium to the tissues and organs. SELENOP also acts to reduce oxidative stress and systemic inflammation [Schöttker 2024; Brezina 2025].
In the Colorectal Cancer Study of Austria (CORSA Study), researchers analyzed data from 519 participants (n = 153 tumor-free controls, n = 255 patients with adenomas, and n = 111 patients with colorectal cancer). The median age of the study participants was 65 years. Nearly two-thirds of the study participants were male. The study participants’ median plasma selenium concentration was a very low 65.7 mcg/L. Their median SELENOP concentration was also low: 2.7 mg/L. During a median follow-up period of 5,424 days (almost 15 years), there were 210 deaths (40 %) [Brezina 2025].
Selenium and COVID-19 and Other Viral Infections
Deficient selenium status is associated with an increased risk of COVID-19 as well as with greater risk of chronic inflammatory diseases and viral infections. However, the biological mechanisms by which selenium deficiency might cause weakened immune function and elevated inflammation are not clearly identified as yet [Golin 2023].
The coronavirus 2, known as SARS-CoV-2, causes COVID-19 illness. COVID-19 is an illness that has infected millions of individuals since late 2019. Acute respiratory syndrome and pro-inflammatory cytokine storms are manifested in the worst of COVID-19 cases. The severity of COVID-19 illness is associated with several factors: age, health status, sex, and selenium deficiency [Golin 2023].
Selenium and Anti-Aging
Selenium is an essential trace element for anti-aging. We do not need much of it. However, our bodies cannot synthesize it for us. We need to get an adequate intake from our food. If necessary, we need to get a little extra from supplements. Selenium plays a role in promoting longevity and in slowing the aging process [Bjorklund 2022].
In many regions of the world, among them much of Europe and the Middle East, the soil and the crops are selenium-poor. For people in these regions, supplementation may be the only way to achieve and maintain a sufficient serum selenium concentration. Current estimates are that the optimal serum selenium status is approximately 125 mcg/L [Rayman 2020].
Selenium and Anti-Aging
Adequate selenium intake is especially important for anti-aging. The selenium element is needed for the synthesis of some 25 known selenoproteins. These selenoproteins have antioxidant, anti-inflammatory, and immune modulating effects. These positive effects link adequate selenium to staying healthier longer in life [Bjorklund 2022].
Sex Differences in Selenium Metabolism
Sex differences in selenium metabolism played a considerable role in the heart health outcomes of the KiSel-10 study. In that randomized controlled trial, the researchers administered 200 mcg/day selenium and 200 mg/day Coenzyme Q10 or matching placebos to elderly Swedish study participants with low selenium status. The combined supplementation significantly improved heart function and reduced cardiovascular mortality [Alehagen 2013].
Note that, on average, the baseline selenium status in the KiSel-10 study participants was at a deficiency level, 67.1 mcg/L. The elderly citizens’ CoQ10 level was only borderline satisfactory, 0.82 mg/L at the study start. Prof. Urban Alehagen and the KiSel-10 research team knew that a low selenium intakes and an aging-related decline in CoQ10 bio-synthesis are associated with increased risk of cardiovascular disease [Alehagen 2013; Alehagen 2020].
Selenium Status and Mortality Risk
All-cause mortality, cancer mortality, and cardiovascular disease mortality are all three significantly associated with selenium status in the blood. Higher selenium status correlates with lower mortality risk. In particular, the inverse relationship with all-cause mortality was strong among different study populations in different countries and in different study regions. The inverse relationship was strong with different selenium measurement methods, with different study recruitment years, and with different study sizes and study follow-up lengths [Cui 2025].
These are the conclusions from a systematic review and meta-analysis of 20 observational studies that enrolled 67,534 study participants. The studies included 17 studies of all-cause mortality, 7 studies of cancer mortality, and 9 studies of cardiovascular disease mortality. The review shows that a concentration increase of one standard deviation in serum or plasma selenium biomarkers was associated with 13% lower all-cause mortality, 15% lower cancer mortality, and 11% lower cardiovascular mortality [Cui 2025].
Selenium and Skeletal Muscle Energy Generation
Selenium is an essential mineral for humans and animals. Selenium deficiency can occur at low dietary intake levels. Sub-optimal and deficiency levels of selenium are associated with negative health outcomes [Wesolowski 2022; Bomer 2020].
Selenium is best known for its biological role as a component of antioxidant selenoproteins, in particular the glutathione peroxidases and the thioredoxin reductases. These antioxidant enzymes protect against
oxidative stress, reduce the extent of systemic inflammation, and regulate
cell death [Wesolowski 2022].
In addition, selenium as a constituent of some 25 known selenoproteins has a variety of physiological functions beyond the antioxidant capabilities. One of the more interesting roles of selenium is the promotion of mitochondrial bio-genesis in skeletal muscle [Wesolowski 2022].