Says team leader Brent Richards "These results are exciting because they demonstrate for the first time that people who have higher levels of vitamin D may age more slowly than people with lower levels of vitamin D.
"This could help explain how vitamin D has a protective effect on many age-related diseases, such as heart disease and cancer. What's interesting is that there's a huge body of evidence that shows sunshine ages your skin—but it also increases your vitamin D levels. So, like many times in medicine, we find there's a trade-off", Richards adds.
The study reported in the American Journal of Clinical Nutrition looked at vitamin D levels in 2,160 women ages 18-79. It examined their white blood cells for genetic signs of aging. The women then were placed into three groups according to their vitamin D levels.
Science has placed telomeres as the most reliable measures of a person's age. These are the lengths of genetic material that cap the free ends of DNA in a cell. With age, the telomeres shorten and the DNA becomes increasingly unstable. Eventually the cell dies.
The study found that those with the highest vitamin D levels had significantly longer telomeres (equivalent to five years of normal aging) than those showing the lowest vitamin D scores.
During summer, much of the vitamin D needed by the body is created by a reaction in the skin, which is powered by sunlight. In winter months where there is less sunshine, vitamin D comes largely from fortified products such as milk, soy milk and cereal grains. It can also be found in cod liver oil, wild salmon, Atlantic mackerel, shrimp and sardines.
"Although it might sound absurd, it's possible that the same sunshine which may increase our risk of skin cancer may also have a healthy effect on the aging process in general," says co-author Tim Spector.
The team of scientists opine that though large-scale trials are needed to confirm the discovery, if proved correct the finding could have a dramatic impact on healthcare.