A large new study suggests that taking vitamin D supplements could help slow down part of the biological aging process.
The study, which is part of the well-known VITAL trial, found that vitamin D may protect telomeres—tiny caps at the ends of chromosomes that help keep our DNA stable and healthy as we age.
The findings were published in The American Journal of Clinical Nutrition and come from a sub-study led by researchers from Mass General Brigham and the Medical College of Georgia.
This is the first time a long-term, large-scale randomized controlled trial has shown that vitamin D supplements can help preserve telomere length in a significant way.
Telomeres are often compared to the plastic tips on the ends of shoelaces. They protect the ends of chromosomes from fraying or sticking to each other.
But as we get older, telomeres naturally get shorter, and this shortening is linked to the development of many age-related diseases, including cancer, heart disease, and autoimmune conditions.
Previous small studies had hinted that vitamin D might help keep telomeres from shortening, but results were mixed and based on short follow-up periods.
The new VITAL Telomere sub-study looked at a group of over 1,000 men and women who took either vitamin D3 (2,000 IU per day), omega-3 fatty acids, or a placebo over several years.
The participants were aged 50 and older for men and 55 and older for women, and they were followed for a total of five years. Researchers measured telomere length at the start of the study, again at two years, and again at four years.
The results showed that people taking vitamin D had significantly less telomere shortening than those taking a placebo.
In fact, the amount of protection offered by the vitamin D supplements was equal to preventing nearly three years’ worth of typical age-related telomere shortening. Meanwhile, omega-3 fatty acids didn’t have a meaningful impact on telomere length during the same period.
Dr. JoAnn Manson, one of the senior authors and head of the VITAL study, noted that this new finding adds to a growing list of benefits linked to vitamin D. Earlier results from VITAL also found that vitamin D can help reduce inflammation and lower the risk of some serious diseases, such as advanced cancer and autoimmune conditions.
Dr. Haidong Zhu, the lead author of the telomere study, explained that while these results are exciting, more research is needed to understand exactly how vitamin D affects telomeres and whether the benefits apply to all people or just specific groups.
However, he said this study points to the possibility that vitamin D could be used as a simple, affordable way to support healthy aging.
In summary, this new evidence suggests that vitamin D supplementation may do more than support bone health and immunity—it might also help protect the body at the cellular level by slowing down a key marker of aging. The results are promising, but experts agree that further research will help confirm how best to use vitamin D in the fight against age-related diseases.
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The research findings can be found in American Journal of Clinical Nutrition.
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