Dr. Lorelei Mucci specializes in prostate cancer epidemiology and her research focuses on cancer risk and mortality in populations across the globe.
Prostatepedia spoke with her about epidemiology’s take on the link between diet, lifestyle, and prostate cancer.
What do we know about diet’s impact on prostate cancer?
Dr. Mucci: Epidemiology studies of diet, lifestyle, and prostate cancer have really evolved a lot over time because of PSA screening and our understanding of the disease’s biologic heterogeneity. With PSA screening, we are both diagnosing more men with prostate cancer and diagnosing more men with a more slow-growing form of prostate cancer.
What we’ve learned is that the relationship between the majority of dietary and lifestyle factors seems to be more associated with the risk of aggressive prostate cancer. We’re starting to see that certain factors are associated with either worse or better survival. It has taken us a while as a field to realize that the relationship of risk factors varies for aggressive versus nonaggressive cancer.
It has also taken us a while to understand the role that PSA screening has played in our studies.
The other consideration with prostate cancer is that it could be many years, if not decades, after diagnosis before a man experiences metastatic disease. Thus, we need long-term follow-up studies to understand the impact of lifestyle factors.
In terms of diet, I don’t think there is yet strong evidence for any particular lifestyle factor to say it is causal. There are some probable factors and some new factors we’re starting to think about.
There is good data on the role of an antioxidant known as lycopene. Lycopene is commonly found in high levels in cooked tomato products such as tomato sauce, but also in things like salsa. What is interesting about lycopene is that it accumulates at high levels in the prostate. A number of epidemiology studies have shown lycopene to be associated with a much lower risk of aggressive prostate cancer. There was a small, randomized study in which men were given capsules of cooked tomato products. The study showed lycopene could make changes in the prostate tumor tissue. So there is probable evidence for cooked tomato products and lycopene in prostate cancer prevention.
We are also starting to see evidence emerge around regular consumption of coffee, either decaffeinated or caffeinated. Coffee is one of the strongest antioxidants available, even stronger than berries. Coffee is interesting for a number of cancers. It seems to be associated with a lower risk of liver cancer, potentially colorectal cancer, and diabetes. In randomized studies, we also see that coffee helps regulate insulin levels after a meal. Insulin may be very important for advanced prostate cancer.
Again, I wouldn’t say this evidence is convincing yet, but we’re starting to see many studies suggesting the benefit of regular coffee consumption.
There is also emerging evidence about fish consumption. In particular, fatty fish like tuna or salmon are associated with a lower risk of aggressive prostate cancer.
On the other side, there is now data suggesting high calcium intake at the levels you’d get more from many supplements may be associated with an increased risk of a more aggressive form of prostate cancer.
Finally, the association between obesity and aggressive prostate cancer is strong. Any dietary factors, or dietary patterns, that contribute to obesity may be associated with more aggressive prostate cancer and with worse outcomes for patients.
Join us to read the remainder of Dr. Mucci’s comments on diet and prostate cancer.