Dairy products, calcium, and vitamin D and risk of prostate cancer.
This review summarizes data of evidence on dairy intake and prostate cancer, which set a background for the existing studies on calcium. It also addresses more specifically the experimental and epidemiological research on vitamin D and prostate cancer and the epidemiological studies on calcium intake and prostate cancer risk. Overall, there is reasonable evidence that both vitamin D metabolites and calcium, and specifically calcium from dairy sources play important roles in the development of prostate cancer. The strongest evidence for an association between calcium intake and risk of prostate cancer comes from the Health Professionals Follow-up Study, in which men who consumed more than 2000 mg of calcium daily had a multivariate relative risk of 4.6 (95% confidence interval: 1.9, 11.1) for metastatic and fatal prostate cancer compared with men consuming <500 mg of calcium daily. This association was independent of age, body mass index, total energy intake, fat, fructose, phosphorous, vitamin D, vitamin E, and lycopene intake. Independent associations were observed for calcium from supplements only and calcium from foods. Given the national enthusiasm to increase calcium consumption in efforts to prevent other chronic diseases, further study of the literature is warranted.