Unravelling the nutritional threads with novel associations of cognitive functions and telomerase

Cognitive decline is a hallmark of brain ageing. Leucocyte telomere length (LTL) has emerged as a candidate biomarker related to brain ageing and neurodegeneration; however, reported associations with cognition and brain structure vary across cohorts. Long-chain omega-3 polyunsaturated fatty acids (PUFA), notably docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), exert anti-inflammatory and antioxidant effects that may, in some contexts, relate to slower telomere attrition. Here, we synthesise evidence on n-3 PUFA, telomere biology and cognitive outcomes, integrating clinical, epidemiologic and experimental data. We emphasise biological plausibility (oxidative stress/inflammation, membrane remodelling, mitochondrial function and expression of telomerase reverse transcriptase (TERT) through PI3K/Akt/mTOR, NRF2 and epigenetic modifications) while acknowledging heterogeneous human findings and methodological considerations (assay variability, life-course timing, cognitive domains and biomarker stratification). We outline priorities for future studies to clarify causal pathways and inform dietary strategies that support healthy cognitive ageing.