Investigating the role of selenium from fish consumption on maternal and child health

Abstract

Selenium (Se) is an essential trace element which is crucial during pregnancy for optimal foetal and child development. Despite fish being a rich source of Se, it also contains methylmercury (MeHg), which may be harmful to the developing foetus. As a result, health agencies advise pregnant women to avoid certain fish. However emerging evidence suggests Se to have a key role in alleviating MeHg toxicity. There is a lack of research on the role of Se on early child growth and development, particularly in populations exposed to Se and MeHg through prenatal fish consumption. The overall aim of this thesis was to investigate the relationship between maternal Se status and child neurodevelopment in a high fish-eating population whilst taking MeHg exposure into account and to investigate factors influencing Se availability using data from the Seychelles Child Development Study(SCDS).

Findings revealed that consuming fish (106g) ensures pregnant women achieve optimum Se intake (61.6 μg/ day) and hence status (102 μg/L) and high ocean fish consumption exposes pregnant Seychellois women to Se in excess of MeHg, which may be protective against MeHg toxicity.

Subsequent analyses examined the associations between maternal Se status and child neurodevelopment, birth anthropometric outcomes and gestational age. Findings from this Se sufficient cohort demonstrated the maternal suboptimal serum Seconcentrations (<89.99 μg/ L) was beneficial to child neurodevelopment at 7 years of age but no at 20 months, however the relationship plateaued. While maternal serum Se and Se:Hg molar ratios were not associated with birth outcomes, afunctional biomarker of Se status, Selenoprotein P (SePP1) was associated with birth Single Nucleotide Polymorphisms (SNPs) found that maternal serum Se status was positively associated with TXNRD1, and significant differences between genotypes were noted, with the CC (102.9 μg/L) and CG (101.9 μg/L) carriers demonstrating significantly greater serum Se concentrations in comparison to GG carriers (99.2μg/L)

Overall, this thesis highlights the benefits of fish consumption in pregnancy for optimal Se status to support child neurodevelopment. It adds to the current evidence of the non-linear relationship between maternal Se status and child development, demonstrating beneficial associations between maternal suboptimal serum Se concentrations (<89.99 μg/ L) and child development. Further work is needed to determine the optimal maternal Se status for child growth and neurodevelopment via oxidative stress pathways and the potential impact of genetics and other factors such as MeHg.

Date of Award	Jun 2026
Original language	English
Supervisor	Maria Mulhern (Supervisor), Sean Strain (Supervisor), Emeir McSorley (Supervisor) & Alison Yeates (Supervisor)