By David Liu, PHDThursday Jan 29, 2013 (foodconsumer.org) -- A new study in the American Journal of Clinical Nutrition suggests that taking high doses of vitamin D as a supplement may increase risk of prostate cancer.The study led by HE Meyer from Department of Community Medicine, University of Oslo in Oslo, Norway and colleagues did not find a direct association between taking vitamin D supplements and risk of prostate cancer.The study actually found that men who had high serum vitamin D in the form of 25-hydroxyvitamn D (25(OH)D), particularly in Summer and Autumn were more likely to be diagnosed with prostate cancer.Although biologically it's possible that vitamin D may prevent prostate cancer, some large studies have shown that high serum vitamin was associated with high risk of prostate cancer, according to the authors.The current nested case-control study was based on data from Norwegian men who participated in population-based studies between 1981 and 1991 who were followed until 2006.  A total of 2106 cases of prostate cancer were identified during the follow-up.  For the study, cases were compared with controls for the association between serum vitamin D and risk of prostate cancer.Overall, it was found that each 30-nmol/L increase in 25(OH)D in the blood was associated with 15% increased risk of prostate cancer.Each 30 -nmol/L increase in serum vitamin D in samples collected in Summer and Autumn was associated with 27% increased risk of prostate cancer although such an increase in Spring and Winter was not at all associated with risk of prostate cancer.It is unclear whether the association between vitamin D levels and risk of prostate cancer is a causal relation.  The study by itself could not prove nor disprove that the increased risk of prostate cancer in men who had high levels of vitamin D was actually caused by high levels of vitamin D.Be aware that not all studies linked vitamin D to increased risk of prostate cancer.  And not all studies are equally trustworthy.   Readers need to do their homework to decide which studies they can trust.Vitamin D deficiency has been associated with more than 100 health conditions including up to 17 types of cancer.The following reports support that vitamin D actually help fight prostate cancer.

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