How Men's Diet Can Reduce Their Risk of Prostate Cancer

From 2015 to 2017, there were 48,487 new cases of prostate cancer. During this time, 11,714 men died from the disease; this accounts for 7% of all deaths attributable to cancer. Since the early 1990's the incidence of prostate cancer has increased by 41% (3). Prostate cancer has several non-modifiable risk factors such as age, ethnicity and family history. However, research is now highlighting some aspects that men do have control over. The World Cancer Research Fund discussed these aspects during a 2014 (16) review. The review found that either overweight or obese men increased their risk of developing an advanced or aggressive form of prostate cancer. The authors summarised their findings by claiming up to 10% of men diagnosed with prostate cancer may have been able to avoid the disease if they had maintained a healthy weight. Laurent et al. (8) supported the obesity link by identifying some of the mechanisms involved in prostate cancer development. More recently, Chen et al. (5) explored the link between diet and prostate cancer and found that a high-fat diet may play a pivotal role in disease progression.

According to the latest figures from Public Health Wales Observatory (14), almost 36% of the nation are overweight or obese. Obesity has increased from 18% in 2003 to 24% in 2016/17. The increasing waistlines of the countries men may indicate why prostate cancer rates are continuing to rise. Part of the rise in prostate cancer cases is also thanks to more sophisticated testing, such as the prostate-specific antigen, which can detect cancer before symptoms start (17).

Prostate Cancer UK (10, 11) recommend that a healthy diet and lifestyle are the best means to reduce prostate cancer risk. The charity draws attention to the 'Eatwell Plate' in their literature, which encourages consuming a balanced diet from a wide variety of foods (13). It is necessary to understand that diet and prostate cancer prevention research is still in its infancy. Nevertheless, scientists are starting to identify some foods that may help reduce the likelihood or slow the growth of prostate cancer:

• Tomatoes, especially those that have been cooked, contain high amounts of lycopene. Lycopene may have anti-cancer properties and decrease cell damage (19).

• High intakes of cruciferous vegetables, such as broccoli, kale and Brussels sprouts, have been linked to lower prostate cancer rates. These types of vegetables could also have antiviral, antibacterial and anti-inflammatory effects (9).

• Soy and legumes; such as beans, peanuts and lentils, may reduce levels of prostate-specific antigen in the blood (9).

• Pomegranates contain an antioxidant that may explicitly target prostate cancer cells (9).

• Habitual green tea consumption may go part of the way to explaining why eastern countries see much lower rates of prostate cancer (6).

Researchers have also identified some foods that may increase prostate cancer risk. The World Health Organisation (WHO) (18) have found a link between red meat consumption and prostate cancer. Red meat becomes particularly problematic when it is cooked at high temperatures, such as barbecuing or frying. This cooking method produces more elevated amounts of certain types of carcinogens. Processed meat is considered a type 1 carcinogen, meaning there is convincing evidence that it causes cancer in humans. However, there is currently no direct link to prostate cancer in particular. It may be worth considering that red and processed meat is the only source of certain essential nutrients in many people's diet. Moderating your intake and choosing safer cooking methods may be more desirable than eliminating it.

Some earlier studies suggested that high dairy intake, equivalent to about 1.6 litres of milk, may increase prostate cancer incidence (4). However, more recent research concluded that the link between the two was not clear, and further investigation was required (15). Dairy contains health-promoting nutrients such as calcium and vitamin D. These nutrients are vital when undergoing hormone therapy, as one of the long term complications is osteoporosis (2). Fortunately, there are now many calcium-fortified non-dairy alternatives for those who wish to reduce their dependence or avoid dairy altogether.

Alcohol has been directly linked to developing seven different types of cancer. However, there is currently no direct link with prostate cancer (1). Despite this, excessive alcohol consumption can contribute to obesity, a known prostate cancer risk (12).

Although vitamin E and selenium are both essential for normal physiological function, there is limited evidence that supplementing these nutrients above the reference nutrient intake could increase the likelihood of developing prostate cancer (7). Therefore, it would be prudent for men to avoid supplements that contain these nutrients in excess amounts.

Taking everything into account, individuals concerned about prostate cancer may wish to seek guidance from a registered health professional, such as a dietitian, before making any drastic changes to their diet. These clinicians will identify suitable areas for improvement and advise what changes can be made whilst ensuring optimal nutrition.

References

1. Cancer Research UK (2018) Does alcohol cause cancer?. Available at: https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/alcohol-and-cancer/does-alcohol-cause-cancer (Accessed: 29 April 2020).

2. Cancer Research UK (2019) What is hormone therapy?. Available at: https://www.cancerresearchuk.org/about-cancer/prostate-cancer/treatment/hormone-therapy/about-hormone-therapy (Accessed: 29 April 2020).

3. Cancer Research UK (2020) Prostate cancer incidence statistics. Available at: https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/prostate-cancer/incidence (Accessed: 27 April 2020).

4. Chan, J.M. et al. (2001) 'Dairy products, calcium, and prostate cancer risk in the Physicians' Health Study'. The American journal of clinical nutrition, 74(4), pp. 549–554.

5. Chen, M., Zhang, J., Sampieri, K. et al. (2018) 'An aberrant SREBP-dependent lipogenic program promotes metastatic prostate cancer'. Nature Genetics, 50, pp. 206–218.

6. Kimura, T. (2012) 'East meets West: ethnic differences in prostate cancer epidemiology between East Asians and Caucasians'. Chinese journal of cancer, 31(9), pp. 421–429.

7. Kristal, A.R. et al. (2014) 'Baseline selenium status and effects of selenium and vitamin e supplementation on prostate cancer risk'. Journal of the National Cancer Institute, 106(3), p.djt456.

8. Laurent et al., (2016) 'Periprostatic adipocytes act as a driving force for prostate cancer progression in obesity'. Nature Communications, 7(1), DOI: 10.1038ncomms10230.

9. National Cancer Institute (2012) Cruciferous vegetables and cancer prevention. Available at: https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cruciferous-vegetables-fact-sheet (Accessed: 29 April 2020).

10. Prostate Cancer UK (2018) Diet, physical activity and your risk of prostate cancer. Available at: https://prostatecanceruk.org/media/2498528/diet-and-your-risk-leaflet-ifm.pdf (Accessed: 27 April 2020).

11. Prostate Cancer UK (2018) Diet and physical activity for men with prostate cancer. Available at: https://prostatecanceruk.org/media/2498529/diet_and_physical_activity_for_men_with_prostate_cancer-ifm.pdf (Accessed: 27 April 2020).

12. Prostate Cancer UK (2019) Frequently asked questions. Available at: https://prostatecanceruk.org/prostate-information/further-help/faq (Accessed: 27 April 2020).

13. Public Health England (2019) The Eatwell Guide. Available at: https://www.nhs.uk/live-well/eat-well/the-eatwell-guide/ (Accessed: 27 April 2020).

14. Public Health Wales Observatory (2019) Obesity in Wales. Available at: http://www.publichealthwalesobservatory.wales.nhs.uk/sitesplus/documents/1208/ObesityInWales%5FReport2018%5Fv1.pdf (Accessed: 27 April 2020).

15. Thorning, T. et al. (2016) 'Milk and dairy products: good or bad for human health? An assessment of the totality of scientific evidence'. Food & Nutrition Research, 60, pp. 1–11.

16. World Cancer Research Fund (2014) Diet, nutrition, physical activity and prostate cancer. Available at: https://www.wcrf.org/sites/default/files/Prostate-Cancer-2014-Report.pdf (Accessed: 27 April 2020).

17. World Cancer Research Fund (2018) Prostate Cancer Statistics. Available at: https://www.wcrf.org/dietandcancer/cancer-trends/prostate-cancer-statistics (Accessed: 29 April 2020).

18. World Health Organisation (2015) Q&A on the carcinogenicity of the consumption of red meat and processed meat. Available at: https://www.who.int/news-room/q-a-detail/q-a-on-the-carcinogenicity-of-the-consumption-of-red-meat-and-processed-meat (Accessed: 29 April 2020).

19. Xu, X. et al. (2016) 'Tomato consumption and prostate cancer risk: a systematic review and meta-analysis'. Scientific Reports (Nature Publisher Group), 6(1), p.37091.