By David Liu, PHD

Wednesday Aug 29, 2012 (foodconsumer.org) -- Eating too much dairy products, milk, butter, and cheese etc, may increase risk for advanced and localized prostate cancer, according to a new study published recently in Journal of Bone and Mineral Research.

The study led by Glovioell W Rowland of University of Southern California in Los Angeles, California and colleagues found African-American Men whose intake of dietary calcium was in the highest quartile were twice as likely as those whose intake was in the lowest quartile to develop localized and advanced prostate cancer.  And high intake calcium was linked to a high risk.

High dietary intake of calcium has been recognized as probable cause of prostate cancer although how the mineral promotes the disease remains unclear, the researchers state in their report.

In the current study, Rowland et al. examined adsorption of calcium in African American men with different statuses of the vitamin D receptor (VDR) which is a key regulator of calcium absorption. VDR expression, according to the researchers, is regulated by the CDX-2 transcription factor through its binding to a polymorphic state in the VDR gene promoter.

Data on dietary and medical information used for the study came from 533 African–American men with prostate cancer cases, 256 advanced prostate cancer and 277 localized prostate cancer, and 250 African–American controls who participated in the California Collaborative Prostate Cancer Study.

In addition to the positive association between calcium intake and risk of prostate cancer, the researchers were also able to find men who absorb calcium less effectively due to their genetic makeup, VDR Cdx2 GG genotype, were 59 percent less likely to develop advanced prostate cancer, compared to other genotypes.

There was a significant association between the gene and calcium, the study found.  Of men with calcium intake below 680?mg per day, carriers of the G allele were about 50 percent less likely to develop prostate cancer, compared with men carrying the AA genotype. 

The researchers concluded "These findings suggest a link between prostate cancer risk and high intestinal absorption of calcium." 

The study did not reveal how individual sources of calcium, dairy products or plant based foods, affect the risk of prostate cancer.  In the West, the most abundant source of calcium is dairy products. The study may suggest that eating too much dairy products, cheese, milk and others may boost the risk.

In fact, prior research has found a link between consumption of dairy products and increased risk of prostate cancer.

For example, Johanna E. Torfadottir of Centre of Public Health Sciences, University of Iceland in Reykjavik, Iceland and colleagues reported a study in the American Journal of Epidemiology saying that men who drank a high amount of milk in adolescence were at 64 percent more likely to develop prostate cancer, compared to those who drank less.  The risk for advanced prostate cancer in those heavy milk drinkers were more than 3 times as high as that in those drinking less.

Dairy products are promoted as a rich source of calcium for bone health.  Some experts argue that although dairy products are rich in calcium, they are not the best calcium people may use to maintain their bone health.  They believe plant-based foods are the better source of calcium.