New results from a large randomized controlled trial called VITAL revealed that vitamin D supplementation helps maintain telomeres, protective caps at the ends of chromosomes that shorten during aging and are linked to the development of certain diseases.
The latest findings, based on data from a VITAL sub-study, support a promising role for vitamin D in slowing a pathway for biological aging.
About the VITAL trial
VITAL is an ongoing research study in 25,871 men and women across the U.S. investigating whether taking daily dietary supplements of vitamin D3 (2000 IU) or omega-3 fatty acids (Omacor® fish oil, 1 gram) reduces the risk for developing cancer, heart disease and stroke in people who do not have a prior history of these illnesses.
Participants, aged 50 years and older, were tracked for five years.
VITAL is the first large-scale and long-term randomized trial to show that vitamin D supplements protect telomeres and preserve telomere length.
The VITAL trial has also shown benefits of vitamin D for reducing inflammation and lowering risks of selected chronic diseases of aging, such as advanced cancer and autoimmune disease.
What are telomeres?
Telomeres are made of repeating sequences of DNA that prevent chromosome ends from degrading or fusing with other chromosomes.
Telomere shortening is a natural part of aging and is associated with an increased risk of various age-related diseases.
A few short-term, small-scale studies have suggested that vitamin D or omega 3 fatty acid supplementation may help support telomeres, but results have been inconsistent.
The latest VITAL findings
The VITAL Telomere sub-study included 1,054 VITAL participants, whose telomere length in white blood cells was assessed at baseline and at year 2 and year 4.
Compared with taking placebo, taking vitamin D3 supplements significantly reduced telomere shortening over four years, preventing the equivalent of nearly three years of aging compared with placebo.
Omega 3 fatty acid supplementation, on the other hand, had no significant effect on telomere length throughout follow-up.
"Our findings suggest that targeted vitamin D supplementation may be a promising strategy to counter a biological aging process, although further research is warranted," said the first author of the report and a molecular geneticist at the Medical College of Georgia.
Source: The American Journal of Clinical Nutrition, May 21, 2025.
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.