Plasma selenium levels and oxidative stress biomarkers: a gene-environment interaction population-based study

Area of Science:

• Environmental health
• Nutritional biochemistry
• Human genetics

Background:

• The role of selenium in chronic disease prevention is debated, especially in populations with adequate selenium levels.
• High selenium concentrations might paradoxically elevate oxidative stress.
• Research on gene-selenium interactions concerning oxidative stress pathways is limited.

Purpose of the Study:

• To investigate the association between plasma selenium concentrations and oxidative stress biomarkers.
• To explore the interactive role of genetic variations in oxidative stress genes with selenium exposure.
• To assess dose-response relationships and identify potential gene-environment interactions.

Main Methods:

• Cross-sectional study of 1445 Spanish adults (18-85 years).
• Measured plasma selenium, and oxidative stress markers: oxidized to reduced glutathione ratio (GSSG/GSH), malondialdehyde (MDA), and 8-oxo-7,8-dihydroguanine (8-oxo-dG).
• Analyzed genetic variations in oxidative stress-related genes and their interaction with selenium levels.

Main Results:

• A geometric mean plasma selenium of 84.76 µg/L was observed.
• Higher selenium levels were inversely associated with GSSG/GSH and MDA, but positively associated with 8-oxo-dG at concentrations above ~110 μg/L.
• Specific genotypes were identified that exacerbated oxidative stress markers under high selenium conditions.

Conclusions:

• High selenium exposure can increase oxidative stress, particularly in certain genetic contexts.
• Nonlinear dose-response relationships exist between selenium and oxidative stress biomarkers.
• Further research is crucial to understand selenium's complex biological roles and gene-selenium interactions in human health.