Vitamin D is involved in a number of vital processes in the body, and the association between low Vit. D levels and various cancers, including prostate cancer, has been extensively studied. Some studies suggest an association but that does not mean that treating with Vitamid D supplementation helps. The first results came from epidemiologic studies known as geographic correlation studies, studies of sunlight exposure( that produces Vit. D) and cancer, and individual studies support the idea that Vitamin D levels tend to be lower in patients with prostate cancer than age matched controls. However, meta-analysie of published literature of studies on vitamin D levels and association with prostate cancer reported little evidence to support a major role of vitamin D in preventing prostate cancer or its progression. Several studies of supplementation of diets of patients with cancer are listed on clinicaltrials.gov, but hard data to recommend testing for Vit D, or supplementation with Vit.D is lacking and there are no guidelines that currently recommend doing so.
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