Vitamin D May Help Slow Down Aging: Study Finds

New Delhi: A new study published in The American Journal of Clinical Nutrition suggests that taking vitamin D supplements could help slow down biological aging at the cellular level. The study found that vitamin D may protect chromosome ends—called telomeres—from shortening, a process closely tied to aging and age-related diseases.

Telomeres are protective caps located at the ends of chromosomes that naturally wear down as we age. When they become too short, cells can no longer divide effectively, leading to cellular aging and a higher risk of conditions such as heart disease and cancer. The shorter your telomeres, the more biologically “aged” your cells are thought to be.

The research team examined data from the long-running VITAL study, a randomized clinical trial involving more than 1,000 participants—women aged 55 and older and men aged 50 and above. Participants were randomly assigned to take either vitamin D3 (2,000 IU/day), omega-3 fatty acids (1 g/day), or a placebo over a span of up to four years. This telomere-focused sub-study specifically aimed to observe whether these supplements could influence the rate of telomere shortening.

The results were promising: individuals who took vitamin D experienced significantly less telomere shortening than those given a placebo. In fact, vitamin D supplementation appeared to slow cellular aging by nearly three years’ worth of telomere decline. Interestingly, omega-3 supplements did not show a similar effect in preserving telomere length.

“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, principal investigator of VITAL. “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.”

Reference: https://news.harvard.edu/gazette/story/2025/05/vitamin-d-supplements-may-slow-biological-aging/