Can Vitamin D and Omega-3 Slow Biological Aging? New Clinical Evidence

Vitamin D and Omega-3 may help slow your rate of biological aging

That’s in addition to their well-established roles in immune function, inflammation control, muscle and bone health, energy regulation, brain function, and cardiovascular health.

But is it really "additional"?

If all those systems are working better, that may well simply be slower biological aging.

That’s the direction of travel suggested by two large human randomised controlled trials, with results published in 2025 (links in the comments)

📑🔍 The DO-HEALTH Bio-Age Trial

Over 2,000 participants were studied using a combination of:

~ 2,000 IU vitamin D3

~ 1g omega-3 fatty acids

~ 3 × 30-minute home exercise programme

Biological ageing was assessed using PhenoAge, a validated biological ageing clock.

All three interventions showed a significant positive effect on biological ageing.

Importantly, participants with lower baseline nutrient status benefited the most exactly what we’d expect.  If you’re deficient or insufficient, moving to sufficiency can produce outsized gains.

📑🔍 The VITAL Trial

This trial followed over 1,000 participants taking:

~ 2,000 IU vitamin D3 daily

~ 1g Marine-sourced omega-3s (EPA & DHA)

Over four years, those receiving vitamin D3 experienced reduced telomere attrition compared to placebo.

Telomeres reflect cellular ageing and replicative capacity. Shorter telomeres are associated with:

~ Higher risk of chronic disease

~ Reduced tissue repair

~ Faster biological ageing

❗ An important caveat

More is not always better.

If your vitamin D and omega-3 status is already sufficient, more does not mean better.

These studies do add to the evidence that 2,000 IU of vitamin D3 and 1g of omega-3 daily is a reasonable, non-excessive dose for most adults.

🔬 Still, test first. Don’t guess.

Vitamin D and omega-3 status tests are widely available, affordable, and highly actionable. Knowing your baseline allows you to personalise intake which is where the real benefit lies.

👉 Bottom Line

Vitamin D and Omega-3 aren’t magic bullets but when used appropriately, based on your own data, they may meaningfully support healthier, slower biological ageing

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

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

Vitamin D3 and marine ω-3 fatty acids supplementation and leukocyte telomere length: 4-year findings from the VITamin D and OmegA-3 TriaL (VITAL) randomized controlled trial

https://pubmed.ncbi.nlm.nih.gov/40409468/

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