Associations of blood mercury and fatty acid concentrations with blood mitochondrial DNA copy number in the Seychelles Child Development Nutrition Study

Research output: Contribution to journalArticle


Background: Fish contains methylmercury (MeHg) which can cause oxidative stress and neurodevelopmental toxicity at sufficiently high doses. Fish also contains polyunsaturated fatty acids (PUFA) which have both antioxidant (n-3) and oxidant (n-6) properties. Mitochondrial DNA (mtDNA) is sensitive to oxidative stress but has not been previously studied in relation to MeHg exposure or PUFA status. Objective: To investigate the associations between MeHg exposure and PUFA status during pregnancy with relative mitochondrial DNA copy number (RmtDNAcn) in mothers and their newborns. Methods: In total, 1488 mother-child pairs from the Seychelles Child Development Study Nutrition Cohort 2 were included in this study. Total Hg was measured in maternal blood collected at 28 weeks’ gestation, maternal hair at delivery, and in fetal cord blood. PUFA (n-3 and n-6) were measured only in maternal blood. RmtDNAcn was measured by qPCR in both maternal and cord blood. Results: Increasing maternal blood Hg (β = 0.001, 95%CI: 0.000, 0.002) and n-3 PUFA concentrations (β = 0.183, 95%CI: 0.048, 0.317) were associated with higher maternal RmtDNAcn. Increasing maternal n-6 PUFA (β = −0.103, 95%CI: −0.145, −0.062) and n-6/n-3 ratio (β = −0.011, 95%CI: −0.017, −0.004) were associated with lower maternal RmtDNAcn. Increasing fetal cord blood Hg was associated with lower fetal RmtDNAcn (β = −0.002, 95%CI: −0.004, −0.000). Neither maternal blood Hg nor PUFA status was associated with fetal RmtDNAcn. Conclusions: Our findings suggest that MeHg and PUFA may influence mitochondrial homeostasis although the magnitude of these associations are small. Future studies should confirm the findings and explore the underlying mechanisms.


  • Yiyi Xu
  • Karin Wahlberg
  • Tanzy M. Love
  • Gene E. Watson
  • Alison J. Yeates
  • Maria S. Mulhern
  • Emeir M. McSorley
  • J. J. Strain
  • Philip W. Davidson
  • Conrad F. Shamlaye
  • Matthew D. Rand
  • G. J. Myers
  • Edwin van Wijngaarden
  • Karin Broberg
External organisations
  • University of Gothenburg
  • University of Ulster
  • Ministry of Health, Seychelles
  • Karolinska Institutet
  • University of Rochester
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Environmental Health and Occupational Health


  • Mercury, Methylmercury, Mitochondrial DNA, Polyunsaturated fatty acids
Original languageEnglish
Pages (from-to)278-283
Number of pages6
JournalEnvironment International
Publication statusPublished - 2019
Publication categoryResearch