Results from a randomized controlled trial reveal that vitamin D supplementation helps maintain telomeres, protective caps at the ends of chromosomes that shorten during aging and are linked to the development of certain diseases.

The new report, which is published in The American Journal of Clinical Nutrition, is based on data from a VITAL (VITamin D and OmegA-3 TriaL) sub-study co-led by researchers at the Harvard-affiliated Mass General Brigham and the Medical College of Georgia, and supports a promising role in slowing a pathway for biological aging.

“VITAL is the first large-scale and long-term randomized trial to show that vitamin D supplements protect telomeres and preserve telomere length,” said co-author JoAnn Manson, the principal investigator of VITAL and chief of the Division of Preventive Medicine at Harvard-affiliated Brigham and Women’s Hospital and the Michael and Lee Bell Professor of Women’s Health at Harvard Medical School.

Trial shows protection against telomere shortening, which heightens disease risk.