11/03/2026
A new Harvard-led study suggests that vitamin D supplementation may slow biological aging at the cellular level. Researchers found that adults who took 2,000 IU of vitamin D3 daily experienced significantly less telomere shortening over four years compared to those taking a placebo. Telomeres are protective caps on chromosomes that naturally erode with age and are linked to inflammation, cancer, and heart disease when they become too short.
The findings come from a sub-study of the large randomized VITAL trial, which followed over 1,000 adults aged 50 and older. Telomere length was measured at the start of the study and again at years two and four. Participants taking vitamin D showed telomere preservation equivalent to nearly three fewer years of biological aging. Omega-3 supplements, also tested, showed no measurable effect.
Researchers emphasize this does not mean vitamin D is an anti-aging cure, but it strengthens evidence that vitamin D supports healthier aging by reducing inflammation and protecting cellular function. Because vitamin D is low-cost and widely accessible, the results point toward a potential population-level strategy to support long-term health as people age.
Sources/Credits: Harvard Gazette (2025); VITAL Trial; JoAnn Manson et al.
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