Fish consumption & polyunsaturated fatty acids (PUFAs) across the lifecycle: implications for cardiometabolic health and ageing

Abstract

Fish is a rich source of long-chain n-3 polyunsaturated fatty acids (PUFAs). Current UK guidelines recommend the consumption of 2 portions of fish per week (equivalent to 280g/week), yet population intakes consistently fall below these recommendations, highlighting a need for stronger public health guidance. This thesis aimed to examine the role of fish consumption and n-3 PUFAs in supporting cardiometabolic health and ageing across the lifecycle. A narrative review highlighted the lipid modifying effects of fish consumption by raising n-3 and lowering n-6 PUFA and triglyceride concentrations. Findings from the high fish-eating Seychelles Child Development Study Nutrition Cohort 2 (SCDS NC2) identified no associations between fish consumption during pregnancy and child weight; however, higher maternal n-6 and lower cord n-3 PUFA concentrations were associated with greater childhood adiposity risk. Dietary pattern analysis within NC2 children at 12-14 years identified patterns characterised by higher fish consumption to be positively associated with intakes of key nutrients, including n-3 PUFAs, reinforcing the importance of fish-based diets for meeting nutrient requirements. An 8-week 2x2 factorial randomised controlled trial investigated the effects of current dietary guidance for fish consumption and omega-3 supplementation as two strategies to improve the omega-3 index (O3I), a marker of CVD risk, amongst low fish consuming young adults. In support of dietary guidelines,2 portions of fish per week or omega-3 supplementation increased the O3I, potentially reducing future CVD risk. Finally, data from the SCDS Main Cohort Mothers identified no associations between fish consumption and telomere length (TL) as a marker of biological ageing; however, non-significant trends suggested higher n-6PUFAs may be associated with shorter TL. Collectively, this thesis supports dietary guidelines and strengthens the evidence base to inform more effective public health policy on the value of fish consumption and n-3 PUFAs in promoting cardiometabolic health across the lifecycle.

Thesis is embargoed until 31 October 2027

Date of Award	Oct 2025
Original language	English
Sponsors	Department for the Economy, United States National Institute of Environmental Health Sciences & Government of the Republic of the Seychelles
Supervisor	Emeir McSorley (Supervisor), Alison Yeates (Supervisor), Maria Mulhern (Supervisor) & Philip Allsopp (Supervisor)