Healthcare (Commonwealth Union) – A randomized trial led by Mass General Brigham indicates that vitamin D may help prevent telomere shortening, a process associated with increased risk of age-related diseases.
Telomeres act as a “molecular clock” for cellular aging. While their shortening is a natural part of aging, lifestyle and potential future therapies might help mitigate their decline, possibly extending health span. However, manipulating telomeres has been approached with caution due to certain diseases.
Vitamin D, often called the “sunshine vitamin,” is essential for strong bones, immune function, and overall health. Unlike other vitamins, our bodies can produce vitamin D when exposed to sunlight. However, many people still suffer from deficiency due to limited sun exposure, dietary gaps, or skin pigmentation. Between 10am to 2pm are said to be the best times for Vitamin D absorption as the, the sun is at its highest point, and UVB rays—responsible for vitamin D synthesis—are most intense.
The new report known as the VITAL randomized controlled trial reveals that taking vitamin D supplements may help slow biological aging by protecting telomeres — the protective caps at the ends of chromosomes that naturally shorten as we age. Published in The American Journal of Clinical Nutrition, the study was co-led by researchers at Mass General Brigham and the Medical College of Georgia. The findings suggest that vitamin D could play a promising role in maintaining cellular health and reducing the risk of age-related diseases.
“VITAL is the first large-scale and long-term randomized trial to show that vitamin D supplements protect telomeres and preserve telomere length,” explained the co-author JoAnn Manson, MD, principal investigator of VITAL and chief of the Division of Preventive Medicine at Brigham and Women’s Hospital, who is a founding member of the Mass General Brigham healthcare system. “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.”
Telomeres are repetitive DNA sequences, known as base pairs, located at the ends of chromosomes. They serve to protect chromosomes from damage and from merging with one another. Over time, telomeres naturally become shorter—a process linked to aging and a higher likelihood of developing age-related health conditions.
Some small and short-term studies have hinted that supplements like vitamin D or omega-3 fatty acids might help maintain telomere length, though the findings have been mixed. The VITAL study—a large, randomized, double-blind, placebo-controlled trial—examined the effects of taking vitamin D3 (2,000 IU daily) and omega-3 fatty acids (1 gram daily) over five years in U.S. women aged 55 and older and men aged 50 and older. A sub-study, called VITAL Telomere, included 1,054 participants who had their white blood cell telomere length measured at the start, at two years, and at four years.
Results showed that, compared to a placebo, vitamin D3 significantly slowed telomere shortening over four years—effectively offsetting nearly three years of biological aging. In contrast, omega-3 fatty acids did not have a notable impact on telomere length during the study period.
Haidong Zhu, PhD, the study’s lead author and a molecular geneticist at the Medical College of Georgia at Augusta University indicated that their results indicate that carefully administered vitamin D supplementation could be a promising approach to slowing aspects of biological aging; however, additional studies are needed to confirm these findings.
This research received funding from the National Heart, Lung, and Blood Institute (grant R01 HL131674-01). The original VITAL trial received support from grant R01 AT011729. The funding agencies had no involvement in the design of the study, the collection, analysis, or interpretation of data, the writing of the manuscript, or the decision to submit it for publication.
