DO-HEALTH trial (777 participants) found that omega-3 (1 g/day) slowed biological aging based on DNAm clocks, with additive benefits from vitamin D (2,000 IU/day) and exercise. Over 3 yrs, aging slowed by 2.9–3.8 months, suggesting a small but good protective effect.

https://www.nature.com/articles/s43587-024-00793-y