Vitamin D extends lifespan

Summary: Vitamin D's positive effect on aging

A study reveals that Vitamin D supplementation slows down the shortening of telomeres, a natural process which takes place as cells multiply. When telomeres reach a certain threshold, cells stop replicating and die.
Slowing down this process could help extend lifespan, as shorter telomeres are linked to aging and age-related diseases. (1)

Vitamin D extends lifespan

This study analyzed the effects of supplementation with Vitamin D3 and omega-3 fatty acids sourced from fish on the lenght of telomeres. It used data from the VITamin D and OmegA-3 TriaL (VITAL) trial.

This trial is a randomized (double blind, placebo controlled) trial, involving 25,871 men and women over the age of 50 years. Prior studies suggested that omega-3 fatty acids and Vitamin D could help promote the health of telomeres, and the VITAL trial was designed to find out if this was true.

What are Telomeres

Telomeres are protective caps located at each tip of the chromosomes that help maintian their structure and stability. As cells divide over a person's lifespan, the telomeres grow shorter. Cells with very short telomeres stop multiplying and die. Shorter telomeres may increase the risks of certain diseases such as cancer, and cardiovascular disease, which in turn decrease lifespan.

If supplementation could slow down the telomere shortening process this could reduce overall mortality, extend lifespan and prevent premature aging and age-related illnesses.

This study analyzed data from a subset of the VITAL trial participants (1,031 subjects), followed over a five-year period and found that:

• Vitamin D3 supplementation reduced the loss of telomere length by 0.14 kilo base pairs over 4 years compared to the placebo group.
• Marine omega-3 supplementation had no significant effect on telomere length.
• " 4-years of supplementation with 2000 IU/day vitamin D3 reduced telomere attrition by 140 bp, suggesting that vitamin D3 daily supplementation with or without n-3 FAs might have a role in counteracting telomere erosion or cell senescence."

Other studies involving VITAL trial data had previously revealed that supplementation with 2000 IU/d vitamin D (without any omega-3 fatty acids) reduced the incidence of advanced (metastatic or fatal) cancer by 17% (3). With or withoug fatty acids it also "reduced all incident autoimmune diseases by 22%, whereas n–3 FAs supplementation with or without vitamin D reduced the autoimmune disease rate by 15% (not statistically significant)"(4).

Very Long Telomers are not good

So, this study shows that Vitamin D supplementation helps preserve telomere lenght. However, very long telomeres may increase the risk of cance according to a 2023 paper (2)

The evidence of genetics

The study involving a genetic mutation leading to longer chromosome tips (long telomeres) it concluded that "Cells with very long telomeres accumulate mutations and appear to promote tumors and other types of growths that would otherwise be put in check by normal telomere shortening processes."

References and Further Reading

(1) Zhu H, Manson JE, Cook NR, Bekele BB, Chen L, Kane KJ, Huang Y, Li W, Christen W, Lee IM, Dong Y. (2025). 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. Am J Clin Nutr. 2025 Jul;122(1):39-47. doi: 10.1016/j.ajcnut.2025.05.003. Epub 2025 May 21. PMID: 40409468; PMCID: PMC12308094

(2) DeBoy EA, Tassia MG, et al. (2025). amilial Clonal Hematopoiesis in a Long Telomere Syndrome.Engl J Med. 2023 May 4. doi: 10.1056/NEJMoa2300503. Online ahead of print. PMID: 37140166.

(3) D. Chandler, W.Y. Chen, O.N. Ajala, A. Hazra, N. Cook, V. Bubes, et al. (2020). Effect of vitamin D3 supplements on development of advanced cancer: a secondary analysis of the VITAL randomized clinical trial. JAMA Netw. Open, 3 (2020), Article e2025850

(4) J. Hahn, N.R. Cook, E.K. Alexander, S. Friedman, J. Walter, V. Bubes et al. (2022). Vitamin D and marine omega 3 fatty acid supplementation and incident autoimmune disease: VITAL randomized controlled trial. BMJ, 376, Article e066452