- Vitamin D3 supplementation (2,000 IU/day) significantly reduced telomere shortening over four years, equivalent to nearly three years of biological aging prevented.
- The VITAL randomized controlled trial is the first large-scale, long-term study to demonstrate this protective effect on telomeres.
- Telomeres, protective caps at chromosome ends, naturally shorten with age and are linked to increased risk of age-related diseases.
- Omega-3 fatty acid supplementation showed no significant effect on telomere length in the same study.
- Findings suggest targeted vitamin D supplementation may be a promising strategy to counteract biological aging processes.
Study Overview
A recent publication in The American Journal of Clinical Nutrition reports that vitamin D supplementation helps maintain telomere length, offering a potential strategy to slow biological aging. This conclusion comes from the VITAL randomized controlled trial, co-led by researchers at Mass General Brigham and the Medical College of Georgia.
The VITAL study tracked U.S. females aged 55 and older and males aged 50 and older over five years, assessing the effects of daily supplementation with vitamin D3 (2,000 IU) and omega-3 fatty acids (1 g). A sub-study involving 1,054 participants measured telomere length in white blood cells at baseline, Year 2, and Year 4.
Expert Insight
“VITAL is the first large-scale and long-term randomized trial to show that vitamin D supplements protect telomeres and preserve telomere length,” said Dr. JoAnn Manson, principal investigator of VITAL and chief of the Division of Preventive Medicine at Brigham and Women’s Hospital. “This is of particular interest because VITAL had also shown benefits of vitamin D in reducing inflammation and lowering risks of selected chronic diseases of aging, such as advanced cancer and autoimmune disease.”
Takeaway for Longevity Enthusiasts
This study underscores the potential of vitamin D3 supplementation as a simple, accessible intervention to slow biological aging by preserving telomere length. While further research is warranted, these findings add to the growing body of evidence supporting the role of vitamin D in promoting healthy aging.
Source
Mass General Brigham. “Vitamin D supplements show signs of protection against biological aging.” ScienceDaily, 21 May 2025.



