Vitamin D may slow biological aging, major study reveals

Vitamin D might be doing more than just supporting bone health; it could also help the body age more slowly, according to a new study led by researchers at Mass General Brigham and the Medical College of Georgia.

The study, published this month in The American Journal of Clinical Nutrition, reveals that taking vitamin D supplements may protect against biological aging by slowing the shortening of telomeres—tiny caps on DNA that naturally erode as individuals grow older.

Conducted as part of a nationwide four-year trial, the research tracked over 1,000 U.S. adults (men over 50 and women over 55) and found that daily vitamin D3 could reduce biological wear and tear, equivalent to nearly three years of aging.

Participants were randomly assigned to take either a placebo or a daily dose of vitamin D3 (2,000 IU) and omega-3 fatty acids (1 gram). Telomere length in white blood cells was measured at the start of the study, at the two-year mark, and after four years.

Compared to the placebo group, those taking vitamin D3 exhibited significantly less telomere shortening. In contrast, omega-3 supplements had no significant effect on telomere length throughout the follow-up period.

This was the first large-scale, long-term randomized trial to demonstrate that vitamin D supplements protect telomeres, according to co-author JoAnn Manson, M.D., the Michael and Lee Bell Professor of Women’s Health at Harvard Medical School.

"This is of particular interest because the VITAL trial has 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," Manson noted.

Telomeres act like protective tips at the ends of chromosomes, akin to the plastic ends of shoelaces. They prevent chromosome ends from degrading or fusing with other chromosomes. Over time, these DNA caps shorten, a natural aspect of aging linked to a higher risk of age-related diseases.

Scientists view telomere length as a marker of biological age, which may better reflect a person’s health status than their chronological age.

While the new findings regarding telomeres do not definitively prove that vitamin D slows aging universally, researchers suggest it points to a potentially powerful method to protect the body at the cellular level.

"Our findings suggest that targeted vitamin D supplementation may be a promising strategy to counter the biological aging process, although further research is warranted," said first author Dr. Haidong Zhu, a molecular geneticist at the Medical College of Georgia.

The research team emphasized the need for additional studies to determine how vitamin D impacts aging in diverse populations and whether these effects persist over time.

Before starting a new supplement regimen, experts recommend consulting with a healthcare provider to discuss proper dosage and potential risks.