A new systematic review and meta-analysis encompassing the most current research has found a distinctly positive correlation between high levels of coffee consumption and a lower risk of prostate cancer. The new research hopes to help bring clarity to an area of study with deeply inconsistent results and suggests, at the very least, coffee consumption may not increase one’s risk for prostate cancer.
In the United States alone over half the population drink at least one cup of coffee every single day. So it is unsurprising that scientists focus quite a bit of attention on the possible health implications of this popular beverage.
The sheer volume of study on coffee’s health effects can be overwhelming. Studies can suggest coffee helps fight obesity, boasts anti-aging qualities, protects from Parkinson’s disease and helps general heart health. And other research can suggest coffee is potentially carcinogenic, leading to a notorious 2018 battle in the US state of California over whether cups of coffee should have cancer warning labels.
The relationship between coffee and cancer is closely studied. While general observational studies have suggested coffee consumption may confer beneficial health effects, one of the larger, more recent, meta-studies suggested there is no difference in cancer risk between coffee drinkers and those who abstain.
Lower rates of prostate cancer in particular have recently been associated with higher levels of coffee consumption. However, the data has proved inconsistent, so this research set out to conduct a new meta-analysis composed of the most up-to-date published research. Sixteen prospective cohort studies were pooled for analysis, comprising more than one million subjects and 57,000 cases of prostate cancer.
The researchers detected a distinct linear trend linking increased volumes of coffee consumption with a decreased prostate cancer risk.
“In the dose-response analysis, a reduction in the risk of prostate cancer of nearly one percent was observed for each increment of one cup of coffee per day,” the researchers write.
This kind of observational association doesn’t mean much without a causal hypothesis, and in the specific case of prostate cancer there are a number of potential mechanisms to explain how coffee could lower one’s prostate cancer risk.
“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 a role in the initiation, development and progression of prostate cancer,” the researchers hypothesize in the study.
A compelling 2019 study zoomed in on the effects on prostate cancer of two particular anti-cancer compounds found in coffee. In mouse models of prostate cancer, kahweol acetate and cafestol seemed to synergistically work to inhibit the growth of cancer cells.
Of course, these kinds of large meta-analyses cannot offer definitive answers. The researchers admit their conclusions should be “interpreted with caution” due to the significantly heterogenous nature of the studies being analyzed. No one is suggesting men increase coffee consumption as a way to protect themselves from prostate cancer, but at least those with prostate cancer concerns can enjoy their daily cups of java without too much worry.
The new research was published in the journal BMJ Open.