TUESDAY, May 27, 2025 (HealthDay News) — Vitamin D supplements might be a veritable Fountain of Youth, capable of slowing down a person’s biological aging, a new study says.
People taking daily vitamin D3 experienced less wear-and-tear on their telomeres, the protective caps of DNA code at the ends of chromosomes, researchers reported in the American Journal of Clinical Nutrition.
Likened to the caps at the ends of shoelaces, telomeres degrade as people get older and are used by researchers as a sign of biological age — the actual amount of aging a person has undergone, as opposed to their age based on their birthday.
The study “is the first large-scale and long-term randomized trial to show that vitamin D supplements protect telomeres and preserve telomere length,” researcher Dr. JoAnn Manson, chief of preventive medicine at Brigham and Women’s Hospital in Boston, said in a news release.
“This is of particular interest because (the trial) 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,” she added.
However, researchers warn not to stock up on vitamin D tablets just yet, as the positive benefits need to be verified in other studies.
“We think these findings are promising and warrant further study, but we think that the replication will be important before changing the general guidelines for vitamin D intake,” Manson told The Washington Post.
For the study, researchers analyzed data for more than 1,000 people participating in a larger, 25,900-person clinical trial testing the benefits of vitamin D and omega 3 fatty acid supplements.
Overall, the trial randomly assigned people to take daily vitamin D3 (2,000 IU/day) or omega 3 fatty acid (1 g/day).
This study focused on a smaller group of people in the study that received regular assessments of their telomere length — at the start of the trial, and then after two and four years of taking the supplements.
Shortened telomeres are thought to decrease the stability of a person’s genetics, increasing their risk for cancer, heart disease, death and chronic illness, researchers said in background notes.
People taking vitamin D3 supplements had significantly reduced telomere shortening over four years, compared to people taking a placebo, researchers found.
However, omega 3 fatty acid supplements had no apparent effect on telomere length, results show.
“Our findings suggest that targeted vitamin D supplementation may be a promising strategy to counter a biological aging process, although further research is warranted,” lead researcher Dr. Haidong Zhu, a molecular geneticist at the Medical College of Georgia, Augusta University, said in a news release.
Manson emphasized that while vitamin D supplements might benefit telomeres, they shouldn’t be considered a substitute for a healthy diet or regular exercise.
“We’ve made it very clear time and again that the focus should be on the diet and lifestyle rather than on supplementation,” she told the Post.
“However, targeted supplementation for people who have higher levels of inflammation or a higher risk of chronic diseases clearly related to inflammation, those high-risk groups may benefit from targeted vitamin D supplementation,” Manson added.
More information
The University of Utah has more about telomeres.
SOURCE: Mass General Brigham, news release, May 21, 2025