Full-fat dairy may protect prostates from cancer
of prostate cancer, says a new study from Hawaii.
The study, by researchers from the University of Hawaii, also reports that the benefits were not related to calcium or vitamin D, opening up possibilities that the bioactive ingredients are a specific type of fat in the milk. "Although the findings from this study do not support an association between the intakes of calcium and vitamin D and prostate cancer risk, they do suggest that an association with milk consumption may vary by fat content, particularly for early forms of this cancer," wrote lead author Song-Yi Park in the American Journal of Epidemiology. Over half a million news cases of prostate cancer are diagnosed every year world wide, and the cancer is the direct cause of over 200,000 deaths. More worryingly, the incidence of the disease is increasing with a rise of 1.7 per cent over 15 years. The Multiethnic Cohort Study (1993-2002) followed 82,483 for an average of eight years. Dietary intakes were evaluated using a detailed quantitative food frequency questionnaire (FFQ). The researchers documented 4,404 cases of prostate cancer, but when they calculated the risks with respect to calcium and vitamin D intake, whether from foods, supplements or in total, no associations were found with prostate cancer. Indeed, this null association was observed across all racial/ethnic groups. In relation to the consumption of dairy products, no associations were again observed. However, when the researchers considered intakes of specific dairy products they noted a significant 12 per cent reduction in total prostate cancer risk by increased whole milk consumption. On the other hand, low-/nonfat milk was related to 16 per cent increased risk. The research appears at odds with an ever-growing body of evidence linking vitamin D status with incidence and risk of various cancers, including breast, colorectal and prostate. "Because dairy products contain a variety of components in addition to calcium, such as fat, protein, lactose, phosphorus, and added vitamin D, the results of [these other] studies may reflect the effects of any of these constituents," wrote the researchers. The link between vitamin D intake and protection from cancer is not and dates from the 1940s when Frank Apperly demonstrated a link between latitude and deaths from cancer, and suggested that sunlight gave "a relative cancer immunity." The new study does have several notable limitations, particularly the use of the food frequency questionnaires which introduce error from subjects' recall accuracy. Also Source: American Journal of Epidemiology Published on-line ahead of print, doi:10.1093/aje/kwm269 "Calcium, Vitamin D, and Dairy Product Intake and Prostate Cancer Risk - The Multiethnic Cohort Study" Authors: Song-Yi Park, S.P. Murphy, L.R. Wilkens, D.O. Stram, B.E. Henderson and L.N. Kolonel