Vitamin D supplements may slow cellular ageing by preventing the shortening of telomeres, DNA sequences at the ends of chromosomes that naturally diminish with age, according to new research.
The study, published in the American Journal of Clinical Nutrition, analysed data from the VItamin D and OmegA-3 TriaL (VITAL), though researchers note the health implications of these findings remain unclear.
Telomeres are repetitive DNA sequences that cap chromosome ends, stabilising them during cell division but becoming shorter each time cells divide.
When telomeres become very short, cells stop dividing and die, contributing to the ageing process.
Participants taking vitamin D daily showed less telomere shortening
GETTYResearchers 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,” the scientist explained, noting this is equivalent to preventing “nearly three years of ageing compared with placebo”.
Conversely, the study found fish oil supplementation showed no significant effect.
The VITAL project involved nearly 26,000 participants aged 50 or older, with researchers examining a subset of 1,054 individuals who had blood drawn three times over four years.
Participants taking 2,000 international units of vitamin D daily showed less telomere shortening compared to the placebo group.
The study found vitamin D supplementation slowed telomere length loss by approximately 140 base pairs over the four-year period. The health implications of this difference in telomere length aren't yet clear.
"It's only at the extremes that telomere length really matters in terms of ageing," cautioned Mary Armanios from Johns Hopkins University, noting the observed difference falls within normal human variation.
However, the findings could explain vitamin D's protective effects against specific ageing-related diseases, including autoimmune conditions and advanced cancers.
JoAnn Manson, a professor of medicine at Harvard Medical School and co-author of the study, suggests these findings could have broader implications.
"If it is replicated in another randomised trial of vitamin D supplements, I think this could translate into clinical effects for chronic diseases of ageing," she said. "This could provide a biological mechanism."
LATEST DEVELOPMENTS
Vitamin D offers protection against age-related diseases
GETTY
Anastassios Pittas, a professor at Tufts University not involved in the study, noted the findings "lend scientific support" to current vitamin D recommendations.
The study has limitations, including concerns about the qPCR methodology used to measure telomere length, which Armanios describes as "the least reproducible" approach.
Most participants were white, prompting researcher Haidong Zhu to call for replication in more diverse populations.
Manson emphasises that vitamin D supplementation "shouldn't be a universal recommendation" but "selected high-risk groups may benefit."
