A daily vitamin D supplement could be the secret to beating aging.

A fascinating first-of-its-kind study found people taking the 10-cent capsule appeared to age at much slower rates.

Over the four-year study, participants who took vitamin D3 had less damage to their DNA — a sign of slower aging. 

It was like turning back nearly three years of aging compared to those who took a dummy pill, the Harvard-affiliated researchers said.

Given the study was relatively short, the team said the results were ‘promising’ and they’ve called for longer research to be conducted.

However, they caution participants in the study took three times the generally recommended vitamin D intake. 

They took 2,000 international units (IU) in pill form every day, the equivalent of two to three servings of salmon or a serving and a half of mushrooms. 

Though they were still in the safe range of 4,000 IU or less, experts have warned taking too much vitamin D can cause calcium to build up in the blood, leading to vomiting and kidney stones.

Researchers at Mass General Brigham found taking vitamin D every day could extend your lifespan by up to three years (stock image)

Dr JoAnn Manson, Chief of the Division of Preventive Medicine at Brigham and Women’s Hospital, a Harvard-affiliated hospital, co-authored the study, dubbed VITAL.

She said: ‘VITAL is the first large-scale and long-term randomized trial to show that vitamin D supplements protect telomeres and preserve telomere length.

‘This is of particular interest because VITAL had also shown benefits of vitamin D in reducing inflammation and lowering risks of selected chronic diseases of aging, such as advanced cancer and autoimmune disease.’

Published Wednesday in the American Journal of Clinical Nutrition, the research saw 1,031 adults either take 2,000 IU of vitamin D every day or a placebo for four years. 

Using blood samples, the team measured the length of each person’s telomeres, repeating sequences of DNA that protect chromosomes from damage. 

Telomeres shorten with age, and previous research shows people with longer telomeres have a longer life expectancy than those with shorter ones. 

The researchers found telomeres were up to eight times longer in people who took daily vitamin D supplements than those in the placebo group.

While it’s unclear exactly how vitamin D lengthens telomeres, experts believe it could help reduce the risk of DNA-damaging oxidative stress and promote the release of enzymes thought to make telomeres longer.

The blood tests measured leukocyte telomere length (LTL), the length of telomeres in white blood cells. 

Shorter LTL has been linked to an increased risk of age-related diseases like heart disease and cancer. 

In the placebo group, LTL decreased 12 percent after two years from the baseline and another 16 percent two years after that. 

However, those who took vitamin D had just five percent less LTL after two years and two percent less two years after that. 

The experts estimate the group that took vitamin D prevented the equivalent of three years of aging compared to the placebo. 

Dr Haidong Zhu, first study author and molecular geneticist at the Medical College of Georgia, said: ‘Our findings suggest that targeted vitamin D supplementation may be a promising strategy to counter a biological aging process, although further research is warranted.’

Telomeres, pictured here, are thought to protect chromosomes from damage. Shorter telomeres have been associated with shorter lifespans (stock image)

While the exact mechanism is unclear, the researchers suggested vitamin D could create higher levels of telomerase, an enzyme that makes telomeres longer. 

Additionally, vitamin D helps lower oxidative stress, an imbalance between disease-fighting antioxidants and harmful free radicals, which attack cells and tissues. Oxidative stress has been shown to damage DNA, potentially shortening telomeres. 

Most experts recommend consuming about 600 to 800 IU per day, significantly less than the 2,000 IU used in the study.

Most vitamin D supplements contain between 1,000 and 2,000 IU. 

Consuming more than 4,000 IU in a day could lead to a dangerous buildup of calcium in the bloodstream. 

This is because vitamin D normally helps the body absorb more calcium, which is crucial for maintaining bone and muscle health.

Excess vitamin D causes the body to absorb more calcium than it needs, causing it to accumulate in the bloodstream and then get deposited into tissues in the kidneys, lungs and heart. 

This leads to nausea, vomiting, constipation, dehydration, bone pain and kidney stones.

There were several limitations, including the lack of diversity in the sample size, as most participants were white. 

The study was partly funded by the National Heart, Lung and Blood Institute, an arm of the National Institutes of Health.