A new US review suggests that people with lower blood levels of vitamin D are twice as likely to die prematurely as people with higher blood vitamin D levels.
The systematic review included the results of 32 studies involving a total of 566,583 participants in 14 count- ries, average age 55 years, investigating the potential association between blood vitamin D concentrations and mortality rates during an average of nine years (1). The results showed that a vitamin D blood level of 30 ng/ml was associated with about half of the death rate compared to significantly lower blood levels.
The researchers commented that the blood concentration of 20 ng/ml recommended by the US Institute of Medicine (IOM) is based solely on the association of low vitamin D with risk of bone disease. The new fin- ding is based on the association of low vitamin D with risk of premature death from all causes, not just bo- ne diseases. Two-thirds of the US population has an estimated blood vitamin D level below 30 ng/ml. The study should give the medical community and public substantial reassurance that vitamin D is safe when used in appropriate doses up to 4,000 International Units (IU) per day, the scientists said. They recom- mended to consult a physician when changing the intake of vitamin D and to have the blood level of 25-hy- droxyvitamin D checked annually. Daily intakes above 4,000 IU per day may be appropriate for some patients under medical supervision.