Effects of Low-Level Organic Mercury Exposure on Oxidative Stress Profile

Background: The fish-based diet is known for its potential health benefits, but it is less known for its association with mercury (Hg) exposure, which, in turn, can lead to neurological and cardiovascular diseases through the exacerbation of oxidative stress. The aim of this study was to evaluate the correlations between Hg blood concentration and specific biomarkers for oxidative stress. Methods: We present a cross-sectional, analytical, observational study, including primary quantitative data obtained from 67 patients who presented with unspecific complaints and had high levels of blood Hg. Oxidative stress markers, such as superoxide dismutase (SOD), glutathione peroxidase (GPX), malondialdehyde (MLD), lymphocyte glutathione (GSH-Ly), selenium (Se), and vitamin D were determined. Results: We found positive, strong correlations between Hg levels and SOD (r = 0.88, p < 0.0001), GPx (r = 0.92, p < 0.0001), and MLD (r = 0.94, p < 0.0001). We also found inverted correlations between GSH-Ly and vitamin D and Hg blood levels (r = −0.86, r = −0.91, respectively, both with p < 0.0001). Se had a weak correlation with Hg plasma levels, but this did not reach statistical significance (r = −0.2, p > 0.05). Conclusions: Thus, we can conclude that low-level Hg exposure can be an inductor of oxidative stress.