Taking vitamin D3 supplements daily could prevent years of biological ageing, according to a new study that could lead to promising strategies for longevity.
The study, published on Thursday in the American Journal of Clinical Nutrition, assessed data from the Vital clinical trial in which US women aged 55 years and older and males aged 50 years and above were tracked for five years after vitamin D3 and omega 3 fatty acid supplementation.
It particularly looked at the effect of supplementation on telomeres in cells, which are repeating sequences of DNA at the ends of chromosomes that prevent them from degrading.
These protective caps of chromosomes shorten during the natural process of ageing and are linked to the development of various age-related diseases.
“Vital is the first large-scale and long-term randomised trial to show that vitamin D supplements protect telomeres and preserve telomere length,” JoAnn Manson, a co-author of the study from Brigham and Women’s Hospital, said.
“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 ageing, such as advanced cancer and autoimmune disease.”
A selection of vitamin supplements (Getty)
While previous short-term, small-scale studies suggested that vitamin D or omega 3 fatty acid supplementation supported telomeres, the results were inconsistent.
In the Vital trial, researchers tracked supplementation of vitamin D3 (about 50mcg a day) and omega 3 fatty acid (1g per day) in the participants for five years.
The telomere length in their white blood cells was assessed at baseline as well as the second and fourth years in about 1,054 of the participants.
Researchers found that taking vitamin D3 supplements significantly reduced telomere shortening over four years.
“Compared to placebo, vitamin D3 supplementation significantly decreased leukocyte telomere length attrition,” they wrote.
This is equivalent to preventing “nearly three years of ageing compared with placebo”.
However, omega 3 fatty acid supplementation did not have any significant effect on telomere length throughout follow-up, they said.
“Our findings suggest that targeted vitamin D supplementation may be a promising strategy to counter a biological ageing process, although further research is warranted,” Haidong Zhu, another author of the study, said.
“Vitamin D3 daily supplementation with or without omega 3 fatty acids might have a role in counteracting telomere erosion or cell senescence.”
This article was amended on 22 May 2025. A previous version referred to a vitamin D3 dosage of 50mg per day, but that was inaccurate and should have referred to 50mcg.
