The Association Between Selenium, Selenoprotein P (SEPP1), Fluid Intelligence, and Exercise in the UK Biobank Cohort

Background: In the mouse hippocampus, exercise boosts neurogenesis. Increased levels of the selenium transport protein selenoprotein P (SEPP1) in the serum of exercised animals may contribute to the impact of exercise. SEPP1 is a protein that aids in the delivery of selenium to the brain. The effect of exercise on mouse brain precursor cell proliferation was diminished when SEPP1 or its receptor were genetically depleted. Selenium supplementation in the diet had the same effect as exercise in reducing some of the cognitive impairments associated with aging. Methods: In the current analysis, we sought to determine the association of selenium, the SEPP1 gene, fluid intelligence, and exercise in the UK Biobank Cohort. We analyzed SEPP1 single nucleotide polymorphism (SNP) rs7579, a single nucleotide variation (SNV), position chr5:42800706, C > T, minor allele frequency T = 0.281. Its consequence is a 3’- UTR variant. The 3′-UTR contains regulatory regions that post-transcriptionally influence gene expression and is responsible for selenoprotein synthesis. SNP rs7579 has been implicated in multiple forms of cancer. The univariate general linear model of SPSS (IBM Corp., Armonk, NY) was used to rule out the effects of age, years of education, and vigorous activity on fluid intelligence score, with fluid intelligence score as the dependent variable, rs7579 genotype, and selenium supplements as fixed factors, and age, years of education, and vigorous activity as covariates. Results: The effect of rs7579 genotype on fluid intelligence score was insignificant (p = 0.702). The effect of selenium supplements on fluid intelligence score was insignificant (p = 0.107). The interaction of rs7579 genotype and selenium supplements was insignificant (p = 0.911) and unrelated to the significant effects of age (p < 0.001), years of education (p < 0.001), and vigorous activity (p < 0.001) on fluid intelligence score. Conclusion: Our multivariate analysis of SEPP1 genotype, selenium supplement use, and fluid intelligence scores is consistent with the negligible effect selenium supplements seem to have on cognition. Selenium is found in nuts, dairy products, and grains. These foods can provide sufficient selenium for health. Selenium supplements are not recommended.