Cancer Research Lab

Intake of calcium and vitamin D has little or no impact on the risk of prostate cancer, but consumption of low fat or nonfat milk may increase the risk of the malignancy, according to the results of two studies appearing in the December 1st issue of the American Journal of Epidemiology.

Calcium and dairy product intake has been thought to increase the risk of prostate cancer by affecting vitamin D metabolism. Data from several prospective studies have supported an association but many other studies have failed to establish a link.

To explore this topic further, Dr. Song-Yi Park, from the University of Hawaii in Honolulu, and colleagues analyzed data from 82,483 men who were enrolled in the Multiethnic Cohort Study (1993-2002) and completed a quantitative food frequency questionnaire.

During an average follow-up period of 8 years, 4404 men developed prostate cancer.

There was no evidence that calcium or vitamin D intake from any source increased the risk of prostate cancer. This held true across all racial and ethnic groups.

In an overall analysis of food groups, dairy product and total milk intake were not tied to prostate cancer risk, the authors found. Further analysis, however, suggested that low fat or nonfat milk increased the risk of localized or low-grade tumors, while whole milk decreased this risk.

In a similar analysis, Dr. Yikyung Park, from the National Institutes of Health in Bethesda, Maryland, and colleagues investigated this topic in 293,888 men enrolled in the NIH-American Association of Retired Persons Diet and Health Study (1995/1996-2001). The mean follow-up period was 6 years.

No link between total or supplemental calcium intake and total or non-advanced prostate cancer was noted. Total calcium intake was tied to advanced and fatal disease, but both associations fell short of statistical significance.

Similar to the first study’s findings, skim milk intake was linked to advanced prostate cancer. Calcium from non-dairy food, by contrast, was tied to a reduced risk of non-advanced prostate cancer.

“Our findings do not provide strong support for the hypothesis that calcium and dairy foods increase the risk of prostate cancer. Results from other large cohort studies, with adequate numbers of advanced and fatal prostate cancers, may shed further light on this question,” Dr. Park’s team concludes.