NEW YORK, May 27:  Vitamin D, long known for its benefits to bone health and immune function, may also play a role in slowing the aging process, according to new research published in The American Journal of Clinical Nutrition.

In a four-year study involving 25,871 participants, researchers found that vitamin D supplements helped slow the shortening of telomeres—the protective caps at the ends of chromosomes that naturally shrink as people age. Shortened telomeres are considered a biomarker of aging and are linked to age-related diseases.

“The finding that these telomeres seem to be protected against shortening, and that their length was being preserved by vitamin D supplementation, suggested that vitamin D may have a role in slowing biological aging,” said Dr. JoAnn Manson, study coauthor and chief of the Division of Preventive Medicine at Brigham and Women’s Hospital, in an interview with Fortune.

Participants in the study also took omega-3 supplements; however, these were found to have no significant impact on telomere length. The results indicated that a daily dose of 2,000 IU (50 micrograms) of vitamin D—taken with or without omega-3s—may help preserve telomere integrity.

The U.S. National Institutes of Health (NIH) currently recommends a daily intake of 600 IU of vitamin D for individuals aged 1 to 70, and 800 IU for those over 70.

Despite the promising findings, Dr. Manson emphasized that supplementation may not be necessary for everyone. “Having a healthy diet and time outdoors, being physically active, will be enough for the majority of the population to have adequate vitamin D status,” she said.

The study adds to a growing body of research exploring how nutritional interventions can support healthy aging at the cellular level.