Dr. Tim Says....

Prostate Cancer

Prostate cancer forms in the tissues of the prostate gland located in the male reproductive system. It is the most common non-skin malignancy in men, and eventually 1 in 6 men will be diagnosed with prostate cancer at some point in their lifetime.

Of those diagnosed, just 1 in 30 will die of the disease, however. Research indicates that most cases of prostate cancer progress so slowly that the patient doesn't ever realize he has it (these cases are identified when an autopsy is performed).¹

Among families who move to the United States from other countries, those who adopt a more Western style diet see an increase in the risk of prostate cancer within two generations - pointing towards diet as an important risk factor. ²

Body Mass Index is another important risk factor: a man is 55% more likely to die of prostate cancer if his BMI is between 30-35 (considered clinically obese), and having diseases like type 2 diabetes double the risk for developing prostate cancer.

Diets high in both saturated and monounsaturated animal fats have been associated with a higher risk of prostate cancer.  Some studies link a specific omega-3 fatty acid, Alpha Linolenic Acid (ALA), to its development because cooking causes the fatty acid to oxidize. ³

ALA can be found primarily in seeds, nuts, and some whole grains. This doesn't mean that you should avoid these foods, however, as the benefits of omega-3 fatty acids in general far outweigh any possible risk.

A higher risk of prostate cancer has also been linked to higher red meat intake ⁴, especially processed meats such as hot dogs and luncheon meats. Generally speaking, vegetarians tend to have a lower incidence of prostate cancer across the board. ⁵

Those who consume the most dairy products, regardless of the dairy's fat content, have as much as a 26% increase in the risk of prostate cancer compared to those who consume the least. Dairy has been found to help prevent other forms of cancer, however, so this is something you should discuss with your physician if you eat a lot of dairy products. ⁶

In the 1990's lycopene, an antioxidant in bright red foods, was linked to reduced risk of prostate cancer. Although currently there is a lack of evidence to show lycopene's specific effectiveness, it's still a good idea to increase your intake of whole bright-colored fruits and vegetables.^7,8

Researchers reported on data from the Health Professionals Followup Study looking at whether at lycopene intake, specifically from tomato sauce, could be correlated with risk of developing a specific type of prostate cancer known as TMPRSS2:ERG-positive prostate cancer. ⁹

After taking into account a wide range of variables, from race to medical history to whether participants took Vitamin E supplements, the authors found that both the highest quintile of lycopene intake and the highest level of tomato sauce intake were associated with a lower risk of prostate cancers of all types, but while higher overall lycopene intake reduced the mens' risk by about 5%, the higher intake of tomato sauce reduced their risk by 10%. Among those cases that were analyzed for ERG status, once again tomato sauce proved more protective than overall lycopene intake.

Studies of the Mediterranean diet (Greek studies in particular) have revealed that higher intakes of selenium, vitamin E, and pulses are linked to lower risk of prostate cancer, as are high plasma Vitamin D levels.¹⁰

A large scale study known as the VITamins And Lifestyle (VITAL) study has linked trace metals such as zinc supplements with a decreased risk of advanced prostate cancer.¹¹ On the other hand, Japanese studies have shown an increased risk of prostate cancer with higher consumption of soybean products, phytoestrogens, and two specific types of omega-3 fatty acids, including eicosapentaenic acid (EPA) and docosahexanoic acid (DHA) from fatty fish. ¹¹

What's the best way to reduce your risk of prostate cancers? Eat a wide variety of fruits and vegetables every day and eat more fatty fish (like salmon or halibut), reduce your consumption of red and processed meats, and avoid highly processed foods and soft drinks.

1. Lamb, A. D., Warren, A. Y., & Neal, D. E. (2011). Pre-malignant Disease in the Prostate. In Pre-Invasive Disease: Pathogenesis and Clinical Management (pp. 467-491). Springer New York.

2. Center MM, Jemal A, Lortet-Tieulent J, et al. International Variation in Prostate Cancer Incidence and Mortality Rates. European Urology. 2012;61(6):1079-1092. doi:10.1016/j.eururo.2012.02.054.

3. Simon, J. A., Chen, Y. H., & Bent, S. (2009). The relation of α-linolenic acid to the risk of prostate cancer: a systematic review and meta-analysis. Am J Clin Nutr, 89(5), 1558S-1564S.  

4. Cross, A. J., Leitzmann, M. F., Gail, M. H., Hollenbeck, A. R., Schatzkin, A., & Sinha, R. (2007). A prospective study of red and processed meat intake in relation to cancer risk. PLoS medicine, 4(12), e325.

5. Chan, J. M., Stampfer, M. J., Ma, J., Gann, P. H., Gaziano, J. M., & Giovannucci, E. L. (2001). Dairy products, calcium, and prostate cancer risk in the Physicians' Health Study. Am J Clin Nutr, 74(4), 549-554.

6. Song, Y., Chavarro, J. E., Cao, Y., Qiu, W., Mucci, L., Sesso, H. D., ... & Ma, J. (2013). Whole milk intake is associated with prostate cancer-specific mortality among US male physicians. J Nutr, jn-112.

7. JNCI J Natl Cancer Inst (2001) 93 (24): 1872-1879.

8. Ilic D, Forbes KM, Hassed C. Lycopene for the prevention of prostate cancer. Cochrane Database of Systematic Reviews 2011, Issue 11. Art. No.: CD008007. DOI: 1002/14651858.CD008007.pub2 - See more.

9. Am J Clin Nutr 2016;103:851-60 

10. Itsiopoulos C, Hodge A, Kaimakamis M (2009) Can the Mediterranean diet prevent prostate cancer? Mol Nutr Food Res 53(2):227-239

11. Mori M, Masumori N, Fukuta F, Nagata Y, Sonoda T, Sakauchi F et al (2009) Traditional Japanese diet and prostate cancer. Mol Nutr Food Res 53(2):191-200

Timothy S. Harlan, M.D.
Dr. Gourmet