Brigham and Women's study finds vitamin D may slow biological aging

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An intriguing new study suggests vitamin D may slow aging inside the body’s cells.

The research comes from the Vitamin D and Omega-3 Trial (VITAL), a huge randomized, controlled trial out of Brigham and Women’s Hospital.

The study focuses on telomeres, which are short, repetitive DNA sequences at the ends of chromosomes. They're often described as “protective caps” because they stop the strands of DNA from getting frayed, tangled or damaged, and they ensure the genetic material encoded in the DNA remains intact during cell division. (Remember, chromosomes are long strands of DNA wrapped around a protein structure; they're found in the nucleus of cells.)

Each time a cell divides, the telomere gets shorter. That shortening is thought to play a role in aging, as well as increasing the risk for chronic diseases like cancer and cardiovascular disease.

Researchers in the Brigham and Women’s study, co-led by a team from Georgia, observed that people who took a daily 2,000 IU supplement of vitamin D3 for four years had less telomere shortening than a control group. The benefit “roughly equates to three fewer years of biological aging over the four years of treatment,” said Dr. JoAnn Manson, the principal investigator of VITAL and one of the study authors, via email.

“Our findings suggest a promising role for vitamin D in slowing a pathway for biological aging and age-related chronic disease,” Manson wrote.

However, she cautioned more research is needed to replicate these results before changing any recommendations about vitamin D intake.

Manson, who leads the Division of Preventive Medicine at Brigham and Women's, has a theory about why vitamin D may have this effect of preserving telomeres.

“This finding is probably related to the benefits of vitamin D in ‘tamping down’ inflammation,” she wrote. “Inflammation is strongly related to aging-related diseases and telomere shortening.“

Earlier research from VITAL has poked holes in many hopes that supplementing vitamin D would do all sorts of good things for health. (It was also the subject of one of CommonHealth’s all-time most clicked articles.)

While Manson and other doctors stress that vitamin D deficiency should be treated, the earlier study found that people without a deficiency saw few benefits from daily supplements. This was true for a range of conditions, including cardiovascular disease, total cancer incidence and cognitive decline. The study also found no significant reduction in the risk for bone fractures with vitamin D supplements.

This new study puts a different spin on vitamin D. But before you run out to buy a supplement, Manson said there are other ways to increase vitamin D levels. They include eating foods rich in vitamin D, such as salmon, tuna and wild mushrooms, or fortified foods like dairy and cereals. Another option is taking a 15-minute walk a few times a week at midday.

Manson said there is still debate over what is an "adequate" blood level of vitamin D, and most medical societies in the U.S. don't recommend testing for everyone. The VITAL trial's results suggest supplements of 2,000 IUs a day are safe over five years. But when it comes to overall health and healthy aging, Manson said it may be even more important to eat right and get plenty of exercise.

“Keep in mind that taking a supplement will never be a substitute for a healthy diet and healthy lifestyle,” Manson said. “Although it’s much easier to pop a pill than to be physically active outdoors and eat healthfully, these lifestyle factors will do more to keep you healthy and lower your risk of cardiovascular disease, cancer, type 2 diabetes, and other chronic diseases of aging.”

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