The importance of vitamin D in health maintenance and longevity is increasingly being recognized. As the vitamin interacts with 3000 genes, and the fact that nearly half of North Americans are deficient in it is cause for concern.
A large study of nearly 250,000 people from Copenhagen has confirmed the importance of vitamin D level. The study shows that persons with the lowest levels (<10 nmol/L) had the highest mortality rates, 2.31 times greater than average.
What turns out to be a surprise, however, was that persons with the highest levels of vitamin D also have increased mortality rates. For those with vitamin D level more than 140, the risk of dying during follow-up was 1.43 times higher than average.
The study found that those with the lowest mortality rates had an ideal vitamin D level of 50 nmol/L.
Though this association is strong, the reason is unknown.
The authors conclude “in this study from the general practice sector, a reverse J-shaped relation between the serum level of 25(OH)D and all-cause mortality was observed, indicating not only a lower limit but also an upper limit. The lowest mortality risk was at 50 – 60 nmol/liter. The study did not allow inference of causality, and further studies are needed to elucidate a possible causal relationship between 25(OH)D levels, especially higher levels, and mortality.”
Clearly it is important to ensure you are taking adequate vitamin D, however the rate of intake must be carefully monitoring and correlated with actual blood levels.