The influence of fish consumption on serum n-3 polyunsaturated fatty acid (PUFA) concentrations in women of childbearing age: a randomised controlled trial (the iFish Study)

Research output: Contribution to journalArticle


PURPOSE: Long-chain polyunsaturated fatty acids (LCPUFA) can be synthesised endogenously from linoleic acid (LA) and α-linolenic acid (ALA) in a pathway involving the fatty acid desaturase (FADS) genes. Endogenous synthesis is inefficient; therefore, dietary intake of preformed LCPUFA from their richest source of fish is preferred. This study investigated the effect of fish consumption on PUFA concentrations in women of childbearing age while stratifying by FADS genotype. The influence of fish consumption on lipid profile, and markers of inflammation and oxidative stress was also examined.

METHODS: Healthy women (n = 49) provided a buccal swab which was analysed for FADS2 genotype (rs3834458; T/deletion). Participants were stratified according to genotype and randomised to an intervention group to receive either no fish (n = 18), 1 portion (n = 14) or 2 portions (n = 17) (140 g per portion) of fish per week for a period of 8 weeks. Serum PUFA was analysed at baseline and post-intervention. Lipid profile, and markers of inflammation and oxidative stress were also analysed.

RESULTS: Participants consuming 2 portions of fish per week had significantly higher concentrations of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and total n-3 PUFA, and a lower n-6:n-3 ratio compared to those in the no fish or 1 portion per week group (all p < 0.05). Fish consumption did not have a significant effect on biomarkers of oxidative stress, inflammation and lipid profile in the current study.

CONCLUSION: Consumption of 2 portions of fish per week has beneficial effects on biological n-3 PUFA concentrations in women of childbearing age; however, no effects on oxidative stress, inflammation or lipid profile were observed. This trial was registered at (NCT03765580), registered December 2018.


  • Marie C Conway
  • Emeir M McSorley
  • Maria S Mulhern
  • Toni Spence
  • Edwin van Wijngaarden
  • Gene E Watson
  • Karin Wahlberg
  • Daniela Pineda
  • Karin Broberg
  • Barry W Hyland
  • Diego F Cobice
  • J J Strain
  • Alison J Yeates
External organisations
  • University of Rochester School of Medicine and Dentistry
  • Karolinska Institutet
  • University of Ulster
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Environmental Health and Occupational Health
  • Nutrition and Dietetics
Original languageEnglish
JournalEuropean Journal of Nutrition
Publication statusE-pub ahead of print - 2020 Jul 28
Publication categoryResearch