A randomized controlled trial titled “Vital” has found that vitamin D supplementation helps to maintain telomeres, which are protective caps at the ends of chromosomes that shorten during aging. This phenomenon is linked to the development of certain diseases. The new report, published in The American Journal of Clinical Nutrition, is based on data from a Vital sub-study co-led by US researchers at the Mass General Brigham and the Medical College of Georgia, and supports a promising role in slowing a pathway for biological aging.