Daily vitamin D3 supplements may reduce biological ageing by preserving chromosome telomeres, a new five-year study reveals.

A recent landmark study published in the American Journal of Clinical Nutrition reveals that daily supplementation with vitamin D3 can significantly slow biological ageing by preserving telomere length—the protective caps on chromosomes that naturally shorten with age.

Researchers analysed data from the Vital clinical trial, which tracked over 1,000 participants aged 50 and above for five years. The trial involved daily doses of 50 micrograms (mcg) of vitamin D3 and 1 gram of omega-3 fatty acids. Telomere length in white blood cells was measured at the start, and again after two and four years.

Results showed that vitamin D3 supplementation markedly reduced the natural shortening of telomeres, effectively preventing the equivalent of nearly three years of cellular ageing compared with placebo. Telomeres play a crucial role in protecting DNA from damage and their erosion is linked to age-related diseases such as cancer and autoimmune disorders.

Interestingly, omega-3 supplementation did not produce a significant effect on telomere length in this trial.

JoAnn Manson, co-author and professor at Brigham and Women’s Hospital, stated: “Vital is the first large-scale and long-term randomised trial to show that vitamin D supplements protect telomeres and preserve telomere length.” She noted the findings align with previous observations of vitamin D’s role in reducing inflammation and lowering risks of chronic age-related diseases.

Lead researcher Haidong Zhu commented, “Vitamin D3 daily supplementation may be a promising strategy to counteract biological ageing, although further studies are needed.”

This study supports the growing evidence that targeted vitamin D supplementation could be a valuable tool in promoting longevity by combating cellular ageing mechanisms.