December 19th, 2011
More Uncertainty About Vitamin D Supplements
Although many experts believe that vitamin D deficiency may play a significant role in cardiovascular disease, there is little evidence to support the use of vitamin D supplements for the prevention of cardiovascular disease. In a narrative review published in Annals of Internal Medicine, Cora McGreevy and David Williams write that the few available studies have been inconclusive and difficult to interpret. More and bigger studies are needed to test the possible beneficial effects of vitamin D supplements, they write.
A second publication in Annals presents an updated meta-analysis of studies of vitamins D and calcium supplements for fracture and cancer protection. The results will inform forthcoming draft recommendations from the USPSTF. Analysis of data from 19 trials and 28 observational studies found that for fracture prevention vitamin D alone was not effective, but that the combination of vitamin D and calcium supplements was effective in older patients. The evidence for vitamin D in cancer prevention is inconclusive, write the authors. An additional area of concern is the proper dosing of vitamin D, since too much vitamin D may cause renal and urinary tract stones.