Take Vitamin D and Live Longer?

Robert W. Griffith, MD

There are plenty of studies that indicate that vitamin D is important for bone health, while some studies show that it may prevent some forms of cancer. A meta-analysis done by French and Italian scientists, which has now been published in the Archives of Internal Medicine, shows that daily vitamin D supplements reduces all-cause mortality. The medical literature was searched for all randomized clinical studies in which vitamin D supplements (vitamin D2 or vitamin D3) were examined for their effects on any health condition.

The total data base comprised 57,000 participants, who were derived from 18 clinical studies that lasted an average of 5-6 years. Daily doses of vitamin D between 300 and 2000 IU were associated with a 7% reduction in deaths from any cause; most of the doses ranged between 400 and 800 IU daily, and achieved a 1.5- to 5-fold increase in serum 25-hydroxyvitamin D compared to the control group of subjects.

If the analysis was limited to those participants who had taken the vitamin D supplements for at least 3 years, the benefit was slightly greater - an 8% reduction in mortality. Calcium supplements were also taken in 13 of the studies, but there were no differences in the results from the studies with and without calcium supplementation.

The authors say it's not clear how vitamin D supplements reduce mortality, but they note that "some effects mediated through the activation of the vitamin D receptor, such as inhibition of cellular proliferation and activation of cellular differentiation, could reduce aggressiveness of cancerous processes and expansion of atheromatous lesions."

An editorial in the same journal calls for large 6-year controlled trials of vitamin D supplementation in people over 50 before these findings lead to any recommendations regarding supplements in the general population. However, physicians should be more proactive in doing serum 25-hydroxyvitamin D levels to see if there are hidden cases of deficiency. It might make sense to add this test to those used in screening older people. And please remember the benefits of sunlight (using appropriate balancing of the possible risks).

Source
HealthandAge Blog

Please take a moment to give us your comments. For questions about Health matters you may check our "Questions & Answers" Portal and Service.