Omega-3 and Biological Ageing: What DO-HEALTH Measured

An analysis published in Nature Aging on 3 February 2025 reported modest changes in biological ageing biomarkers following omega-3 supplementation. The study was a post hoc analysis of the DO-HEALTH trial, rather than a trial demonstrating longer life. [1]

What was tested?

Researchers studied 777 Swiss participants aged 70 or older over three years. The interventions included one gram of algae-derived omega-3 daily, 2,000 IU of vitamin D daily, and a 30-minute home strength-training programme three times a week, tested individually and in combinations. [2]

The analysis examined DNA methylation-based “clocks,” which use chemical patterns associated with ageing to estimate biological age or the pace of ageing. These measurements are research tools rather than a direct count of healthy years gained. [1,2]

What did the researchers find?

Omega-3 showed small effects on three measures: PhenoAge, GrimAge2 and DunedinPACE. The combination of omega-3, vitamin D and exercise showed an additive effect on PhenoAge. The paper reported changes equivalent to approximately 2.9–3.8 months on the PhenoAge and GrimAge2 measures over the three-year period. This is not an observed extension of lifespan. [1]

The University of Zurich highlighted the absence of a universally accepted standard for measuring biological ageing. It also noted that a Swiss sample cannot represent the global older population. [2]

Why the distinction matters

The useful next question is whether biomarker changes reliably correspond to meaningful health outcomes over longer periods and in different populations. A small shift in a laboratory-derived measure alone cannot answer that question.

The findings also relate to specific interventions, doses and participants, not to every supplement containing omega-3. They offer a research signal worth investigating, rather than proof of longevity or a reason, by themselves, to start or change supplementation.