People who have low levels of vitamin D in the blood are likely to die early, according to a new study.
Researchers found that people with less than 10 nanograms/millilitre of vitamin D in their blood has a high risk of facing death over a nine-year period, than people who had about 30 nanograms/ml of vitamin D.
The finding came from 32 previous studies that included examining vitamin D blood levels and mortality rates in over 500,000 people across 14 countries. The investigators analysed the levels of 25-hydroxyvitamin D, the major form of vitamin found in blood.
The survey suggested that people should increase their targeted level of vitamin D. The Institute of Medicine (IOM) had recommended 20 ng/ml as the minimum healthy amount of vitamin D three years ago, study author Cedric Garland, professor in the Department of Family and Preventive Medicine at UC San Diego told to Live Science.
The same IOM report also suggested that most people in the US get enough of vitamin D to maintain a healthy life.
But Garland said the recommendation for that amount was based only on the association between low vitamin D and the risk of bone disease.
Around two-thirds of people in the US have blood levels of vitamin D below 30 ng/ml, according to Garland.
Garland's suggestion is based on his latest study that showed the link between vitamin D levels and the risk of premature death, whereas the recommendation made by IOM was based on the link between vitamin D levels and the risk of bone disease.
The key reason for vitamin D deficiency is usually inadequate exposure to sunlight. It is recommended that people spend at least 10 minutes a day in sunlight. Though consuming supplements may also help in getting enough of the vitamin D.
"In general, it is a good study," said Dr. Eric Newman, Mercy Medical Center in Baltimore, who was not directly involved in the study.
"Vitamin D is important in so many aspects, including cancer prevention and overall well-being, he added, pointing to salmon, sardines and egg yolks as good nutritional sources of vitamin D. It is difficult to get the amount [of vitamin D] you need entirely through diet," Newman said, adding that adequate exposure to the Sun is the best way to get enough of the vitamin.
The details of the study was published in the American Journal of Public Health.