Vitamin D could reduce the risk of premature death

Vitamin D: less risk of premature death

High serum vitamin D concentrations are associated with a lower risk of premature mortality. In subjects with at least 30 nanograms per milliliter of 25[OH]D, a precursor to the vitamin, the risk of early death is reduced by about half, compared with those with lower concentrations.

This is the result of a study published in theAmerican Journal of Public Health. The research, conducted by researchers at the University of San Diego, California, looked at numerous studies conducted in recent years on the relationship between vitamin D and mortality.

The sunshine vitamin

Vitamin D is a fat-soluble molecule involved in calcium and phosphorus metabolism, and exists in two forms: cholecalciferol (Vitamin D3) and ergocalciferol (Vitamin D2). However, the dietary intake of vitamin D is often insufficient for daily needs. Among foods, only certain types of fish such as cod, tuna, salmon and sardines can provide decent amounts of the vitamin. Ninety percent of the molecule in the human body is produced through exposure to the sun's ultraviolet rays. Both forms of the vitamin undergo two transformations in the body: the first in the liver with formation of 25(OH)D, the second in the kidney where 1,25(OH)D is formed. The latter represents the active form of the vitamin, a hormone that acts mainly by increasing intestinal absorption of calcium, regulating bone reabsorption and, at the kidney level, phosphorus reabsorption.

Vitamin D reduces the risk of premature death from all causes

During the research, scientists looked at 32 studies, published between 1996 and 2013, analyzing data from 566,583 men and women. The results showed that a vitamin D level of 30 ng/ml in serum is associated with a 50 percent reduction in the risk of death, compared with lower concentrations. According to the researchers, a concentration of 30 ng/ml is found in about two-thirds of the U.S. population. In previous years, another study had concluded that having a low level, less than 20 ng/mL, in the blood of vitamin D was detrimental to health. This threshold value referred only to the risk of bone disease. Instead, the new finding is based on the association between low vitamin D concentration and the risk of premature death from all causes.

Appropriate doses of vitamin D benefit health

According to Heather Hofflich, a researcher at the University of San Diego, this study should provide the medical community and the public with confidence that vitamin D is safe when used in appropriate doses, that is, up to 4,000 IU per day (i.e., about 100 µg). However, it is always advisable to consult your doctor when increasing your vitamin D intake and to check your blood level of 25-hydroxyvitamin D every year.

Source Cedric F. Garland, June Jiwon Kim, Sharif Burgette Mohr, Edward Doerr Gorham, William B. Grant, Edward L. Giovannucci, Leo Baggerly, Heather Hofflich, Joe Wesley Ramsdell, Kenneth Zeng, and Robert P. Heaney. "Meta-analysis of All-Cause Mortality According to Serum 25-Hydroxyvitamin D." American Journal of Public Health: August 2014, Vol. 104, No. 8, pp. e43-e50.doi: 10.2105/AJPH.2014.302034