A recent large study from Norway found lower risk of prostate cancer among drinkers of boiled coffee. The study entitled “Boiled coffee consumption and the risk of prostate cancer: follow-up of 224,234 Norwegian men 20–69 years”, was recently published in the British Journal of Cancer.
According to a report published in 2007 by the World Cancer Research Fund/American Institute for Cancer Research, the strength of evidence concerning the relationship between coffee consumption and prostate cancer is graded as ‘limited—no conclusion’. Since the release of this report, studies have been showing contrasting results varying from no association to inverse associations between coffee intake and prostate cancer. Furthermore, a previous study examining the intake of boiled vs filtered coffee in relation to several cancer types revealed no result for prostate cancer.
Two diterpenes named cafestol and kahweol are substances present in boiled coffee that have been found to demonstrate anti-carcinogenic activity. A paper filter can trap most of these substances. In this regard there may be a difference in the coffee–prostate cancer relationship if we considered boiled (non-filtered) coffee vs non boiled coffee.
Lead author and researcher Dr. Aage Tverdal from the Department of Pharmacoepidemiology at the Norwegian Institute of Public Health, Norway, prospectively examined the relationship between boiled and non-boiled coffee and the risk of prostate cancer.
The patient sample was obtained from the Norwegian cardiovascular screening programme and included a total of 224,234 men aged between 20-69 years, were coffee habits were asked, from 1985 to 1999. From this sample, 5740 cases of incident prostate cancers were identified.
Results from the study revealed that compared to men who do not drink coffee, men who drink <1–4, 5–8 and 9+ 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), respectively. The corresponding results for non-boiled coffee were 0.89 (0.80–0.99), 0.91 (0.81–1.02) and 0.86 (0.74–1.00), respectively.
Findings from this large follow-up study strongly suggest that there is a lower risk of prostate cancer among heavy drinkers of boiled coffee compared to drinkers of other types of coffee, with an inverse relationship between the number of cups per day and the risk of prostate cancer present only in men who drink boiled coffee.