Low serum concentrations of selenoprotein P (SELENOP) are an indication of increased heart health risks. Low serum SELENOP is strongly associated with the following risks:
- increased risk of a first cardiovascular event
- increased risk of cardiovascular mortality
- increased risk of all-cause mortality
This is the conclusion from a relatively large study of adults in Sweden. The study participants had no history of cardiovascular disease at the beginning of the study [Schomburg 2019].
There were 3,531 non-smokers and 835 smokers enrolled in the study in Sweden. At the end of the study, the study participants at increased risk of cardiovascular disease had a mean serum SELENOP level below 4.3 mg/L SELENOP. This serum concentration of SELENOP corresponds to serum selenium concentrations of less than 70 mcg/L [Schomburg 2019].
Generally Low Selenium Intakes in the Nordic and Baltic Countries
In the Swedish study, the study participants with higher levels of serum SELENOP had a significantly lower risk of a first cardiovascular event involving coronary artery disease or stroke [Schomburg 2019].
The content of selenium in food varies according to the availability of selenium in the soil and in crops. The soil in most areas of the Nordic and Baltic countries is poor in selenium [Alexander 2023].
People living in Sweden and the other Nordic countries and the Baltic countries have relatively low intakes of selenium. The exception is people living in Finland. They have higher selenium intakes than their Nordic and Baltic neighbors because Finland fertilizes crops with selenium [Blomhoff 2023].
The estimated selenium intake per day in Finland is 88 mcg in men and 68 mcg in women. Thus, in Finland, the average selenium concentration in plasma is approximately 110 mcg/L [Alexander 2023].
In the Nordic countries and in the Baltic countries, selenium intakes range from 39 to 88 mcg/day in men and 22 to 68 mcg/day in women. It can be seen that the highest levels in the region are from Finland [Alexander 2023].
However, Haug et al have noted that only a small proportion of the selenium in soil fertilizer is taken up by plants. Much of the selenium in fertilizer is lost for future use. Furthermore, given the demands of industry for selenium, there is not enough available selenium to permit the selenium fertilization of the soil in all of the selenium-poor regions of the world [Haug 2007].
Beneficial Health Effects from Selenium Supplementation
Too often, intervention studies of selenium supplementation are conducted in so-called “selenium-replete” populations, i.e., in study participants with an adequate intake of selenium. These studies are less likely to show a health benefit from selenium supplementation, compared to placebo. On the other hand, selenium supplementation of individuals low in selenium do suggest an associated beneficial effect. Moreover, observational studies have also indicated an inverse relationship between selenium status and risk of cardiovascular disease and mortality [Alexander 2023].
Prof. Lutz Schomburg and his fellow researchers concluded as follows: in northern Europe, the 20% of the adult population with the lowest SELENOP concentrations have a markedly increased risk of cardiovascular morbidity and mortality. This is likely the case even if these individuals do not have a history of cardiovascular disease. For these individuals, preventive selenium supplementation studies are warranted [Schomburg 2019].
Combined Selenium and Coenzyme Q10 Supplementation in the KiSel-10 Study
In the randomized controlled KiSel-10 trial, researchers enrolled elderly Swedish citizens with a quite low baseline serum selenium level, on average, of 67 mcg/L. Daily supplementation with a combination of 200 mcg/day selenium and 2 x 100 mg/day Coenzyme Q10 for four years significantly reduced cardiovascular mortality, compared to placebo. The beneficial effect of the combined supplementation was significantly higher in the two lowest tertiles of baseline serum selenium. The tertiles were as follows [Alehagen 2016]:
- Below 65 mcg/L
- Between 65–85 mcg/L
- Above 85 mcg/L)
The significant reduction in cardiovascular mortality persisted for another eight years after the cessation of the supplementation. The KiSel-10 study outcomes strongly suggest that cardiovascular risk reduction is possible through selenium supplementation of individuals with low selenium intakes and status [Alehagen 2018, Alexander 2023].
Conclusion: Selenoprotein P and Cardiovascular Disease Risk
We need a sufficient daily intake of selenium for the synthesis and maintenance of SELENOP and other selenoproteins, in particular those that have antioxidant properties and that regulate thyroid hormones.
Circulating levels of SELENOP in the plasma are the most appropriate biomarker of sufficient selenium intake.
The intake of selenium from food varies according to the selenium content of the soil and the crops in a region. The Nordic and Baltic countries are a selenium-poor region.
In individuals low selenium and SELENOP status but not in individuals with sufficient selenium and SELENOP status, selenium supplementation may reduce the risk of cardiovascular disease
Sources
Alehagen U et al. Supplementation with selenium and Coenzyme Q10 reduces cardiovascular mortality in elderly with low selenium status. a secondary analysis of a randomized clinical trial. PLoS One. 2016 Jul 1;11(7):e0157541.
Alehagen U et al. Still reduced cardiovascular mortality 12 years after supplementation with selenium and coenzyme Q10 for four years: a validation of previous 10-year follow-up results of a prospective randomized double-blind placebo-controlled trial in elderly. PLoS One 2018; 13(4): e0193120.
Alexander J, Olsen AK. Selenium – a scoping review for Nordic Nutrition Recommendations 2023. Food Nutr Res. 2023 Dec 28;67.
Blomhoff R et al. Nordic Nutrition Recommendations 2023. Copenhagen: Nordic Council of Ministers, 2023.
Haug et al. How to use the world’s scarce selenium resources efficiently to increase the selenium concentration in food. Microb Ecol Health Dis. 2007 Dec;19(4):209-228.
Hughes DJ et al. Selenium status is associated with colorectal cancer risk in
the European prospective investigation of cancer and nutrition cohort. Int. J. Cancer. 2015;136:1149–1161.
Schomburg L et al. Selenoprotein P deficiency predicts cardiovascular disease and death. Nutrients. 2019 Aug 9;11(8):1852.
The information presented in this review article is not intended as medical advice. It should not be used as such.