Evidence Suggests That Drinking Coffee Decreases Prostate Cancer Risk
A new meta-analysis of studies looking at coffee consumption and prostate cancer risk has found higher consumption linked to lower overall risk and even greater reductions for advanced prostate cancer and fatalities.1
This may be the largest study on this topic (involving more than one million men), but other studies with very similar findings go back over a decade. In fact, there have been findings related to coffee drinking reducing the risk for bladder, breast, bowel, and other cancers as well.
New direction in research may be needed
One thing all of the PCa studies seem to have in common is a call for further direct research on coffee. Some of the studies note potential reasons coffee may reduce cancer risk, but the new study finally calls for examining the component parts or qualities that bring about the benefits, but doesn’t seem to go nearly far enough.
In addition, of particular interest to many of the men at this site, my dive into the research uncovered a study finding similar benefits related to the risk of recurrent prostate cancer.
This new analysis, published in BMJ Open, looked at 16 studies up to September 2020 and included 57,732 prostate cancer cases and more than one million total study members.1 The highest rates of coffee consumption in the included studies ranged from two to nine cups a day (note: this high range is a potential flaw for drawing inferences on what exactly is high consumption, but the number of included studies and huge number of subjects help with this), and the low end ranged from zero to less than two.
Looking at the data across the studies, the researchers found a reduction in prostate cancer risk of 9% from the lowest to highest levels of consumption, and a 1% decrease with each additional cup of coffee.1
When the analysis is broken down into levels of cancer severity, the benefits become even more stark. They found a 7% decrease from lowest to highest consumption in localized PCa, but a 12% decrease for advanced PCa. Best yet, the highest level was associated with a 16% decrease in fatal PCa.1
Previous research on coffee and prostate cancer
As I previously stated, this was far from the first study of coffee and PCa. The authors noted that while the earliest research was inconclusive, more recent studies have found the same connection.4 There was another meta-analysis from 2014 that looked at all the studies the researchers were able to locate up to June 2013.5
The concluding statement - that “Our meta-analysis suggests that high (e.g., highest ≥ 4 or 5 cups/day) coffee consumption may not only be associated with a reduced risk of overall prostate cancer, but also inversely associated with fatal and high-grade prostate cancer” - sounds an awful lot like the conclusion of the recent meta-analysis.5
Similar findings were previously reported in a 2011 study, which tracked the coffee consumption of 47,911 men every four years from 1986 to 2008 and the incidence and severity of any prostate cancer.7 For those consuming 6 or more cups, overall risk lowered nearly 20%, and there was a 60% lower risk of developing lethal PCa.7 In addition, this study found no significant difference between caffeinated and decaffeinated coffee and that one to three cups of coffee a day showed a 30% lower risk of lethal PCa.7
Investigating the potential implications
I mention these two older studies not only to demonstrate the strength of the relationship between increased coffee intake and lower risk of PCa, but also to ask a question. At what point does research move to the next level? I’m a research guy and all for thoroughness and validation through replication, but there is a point when repeated research findings should direct researchers to investigate the potential implications of those findings.
The authors of the 2011 study chose to look at coffee “because it contains many beneficial compounds that act as antioxidants, reduce inflammation, and regulate insulin, all of which may influence prostate cancer.”7
The 2021 study says, “Coffee improves glucose metabolism, decreases concentrations of plasma insulin and insulin-like growth factor-1, has anti-inflammatory and antioxidant effects, and affects sex hormone levels, all of which may play roles in the initiation, development and progression of prostate cancer.”1,8 They are citing many of the same fundamental elements.
Yet, where is the call to investigate how these elements may be harnessed to help men avoid PCa or the worst of PCa, without having to spend the whole day drinking coffee and enduring any non-PCa-related negative health effects that may entail?
The 2021 study concludes, “Further research is still warranted to explore the underlying mechanisms and active compounds in coffee. If the association is further proved to be a causal effect, men might be encouraged to increase their coffee consumption to potentially decrease the risk of prostate cancer.”1,9 So close and yet so far.
They fall back again on replicating the findings of the last decade. This is especially frustrating, given the research finding that coffee reduces the risk of other cancers as well.10
Evidence of recurrence risk decrease
Of particular interest to most of the men in this community is how such research relates to those already diagnosed with prostate cancer. I came across information on a 2013 study that found drinking one cup of coffee a day resulted in a 56% decrease in risk of recurrence or progression compared to drinking one cup or less a week.11
These numbers seem very impressive, however, the lead author noted that: “For men who do not drink coffee, it is not possible to recommend that they start drinking coffee based on results from our observational study, especially as some of these men may have medical conditions that could be exacerbated by caffeine or coffee intake.”11
This statement mirrors what I said above and further reinforces the need for researchers to move to see if the potentially beneficial components of coffee can be utilized independently to reduce the overall risk of prostate cancer or its most severe forms, as well as the risk of recurrence for those unlucky enough to already have had to live through it.
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