A new study from Norway found that men who drink boiled coffee may have a lower risk of prostate cancer. The study was conducted by Dr. Aage Tverdal of the Department of Pharmacoepidemiology at the Norwegian Institute of Public Health and was published in the British Journal of Cancer.
The study came after a report published in 2007 by the World Cancer Research Fund/American Institute for Cancer Research said there is limited evidence linking coffee and prostate cancer. Since this report, studies such as this one have been coming out showing either no link between the two or linking the two. One study compared boiled coffee to filtered coffee among a few different types of cancer, but the results did not relate to prostate cancer.
The evidence within this study which strengthens the relation between boiled coffee and prostate cancer comes from two diterpenes – cafestol and kahweol – which are substances present in boiled coffee which have been found to have anti-carcinogenic effects. The coffee’s paper filter can actually trap these substances. Boiled coffee is non-filtered. When comparing boiled coffee to non-boiled coffee in relation to prostate cancer, it is this evidence which differentiates this study from the rest.
The study involved 224,234 men between ages 20-69 years old. Samples were taken from the Norwegian cardiovascular screening program. From 1985 to 1999, these patients coffee habits were recorded. Of this group, there were 5,740 prostate cancer cases found.
For boiled coffee, men who drank one to four, five to eight, or nine or more cups per day of boiled coffee had hazard ratios of 0.84 (0.73–0.96), 0.80 (0.70–0.92) and 0.66 (0.55–0.80). For non-boiled coffee, hazard ratios were 0.89 (0.80–0.99), 0.91 (0.81–1.02) and 0.86 (0.74–1.00). Both were compared to men who do not drink coffee. According to the National Cancer Institute, the hazard ratio is a measure of survival at any point in time in a group of patients who have been given a specific treatment compared to a control group given another treatment or a placebo. A hazard ratio of one means that there is no difference in survival between the two groups. A hazard ratio of greater than one or less than one means that survival was better in one of the groups.
The results suggest that there is a lower risk of prostate cancer among men who drink boiled coffee as opposed to men who drink non-boiled coffee. There is also an inverse relationship between the prostate cancer risk in men who drank boiled coffee the number of cups these men drank per day.