Researchers at the University of Zurich ran a three-year trial giving 777 older adults vitamin D, omega-3, a home exercise program, or combinations of the three, then measured several DNA-methylation clocks of biological aging before and after.
Omega-3 alone slowed three separate aging clocks, including GrimAge2 and DunedinPACE, and all three treatments combined had an additive benefit on a clock called PhenoAge. Across the trial, the standardized effects translated to slowing the clocks by roughly three to four months over three years, a small but measurable shift.
The result stands out for testing an inexpensive, over-the-counter intervention in a large randomized trial measured against several DNA-methylation aging clocks at once. The effect size is small, the trial ran only three years, and the authors note this is a post hoc analysis of a larger study originally designed around fracture and infection outcomes, not biological aging itself.
Read the original study
Bischoff-Ferrari et al., Nature Aging, 2025 · doi.org/10.1038/s43587-024-00793-y
Three years of follow-up, a few months on the clock.
Source
- Bischoff-Ferrari, H. A., Gängler, S., Wieczorek, M., Belsky, D. W., Ryan, J., Kressig, R. W., Stähelin, H. B., Theiler, R., Dawson-Hughes, B., Rizzoli, R., Vellas, B., Rouch, L., Guyonnet, S., Egli, A., Orav, E. J., Willett, W., & Horvath, S. (2025). Individual and additive effects of vitamin D, omega-3 and exercise on DNA methylation clocks of biological aging in older adults from the DO-HEALTH trial. Nature Aging, 5(3), 376–385. https://doi.org/10.1038/s43587-024-00793-y