Prostate Cancer Treatment & Prevention – What Is The Evidence For Diet & Targeted Nutrition?
The lifetime risk for developing invasive prostate cancer is 1 in 6, making it the most common cancer among North American men. Prostate cancer usually starts as a slow-growing cancer, but can become more aggressive 10-15 years later.
The standard treatment options for invasive prostate cancer are extreme: prostatectomy (removal of the entire prostate) and complete hormone blockade (to block testosterone production). As you can imagine, these treatments have a substantial side effect profile – including incontinence, erectile dysfunction, bowel complications, fatigue, depression and loss of muscle mass. The quality of life impact is significant to say the least.
Due to the significant morbidity associated with these definitive treatments, more clinicians are favoring active surveillance (AS) or a watch-and-wait approach for those who have non-aggressive, localized, low-risk disease. This generally includes those prostate cancers with a low PSA doubling time, Gleason score 6 (3+3) or low-volume Gleason 7 (3+4), non-palpable disease on exam, stage T1 or T2 and no evidence of extracapsular extension on mpMRI (multiparametric MRI – this is not usually covered by the medical services plan in Canada, but is available through private-pay imaging with a referral).
As an emerging strategy for management of favorable-risk prostate cancer, AS regimens that are commonly used involve closely monitoring low risk prostate cancer patients for any sign of disease progression and may include one or more of the following: routine PSA tests, biopsies and/or mpMRIs. The goal of any AS program is to try and avoid or delay the side effects of treatment but also to maintain the option of delayed intervention with more aggressive measures if and when needed.
Many institutions in the U.S and abroad are starting to adopt a more comprehensive AS program that includes modification of lifestyle and dietary behaviors, along with targeted nutrition using evidence-supported nutrients and botanicals.
Below are the top 7 lifestyle, dietary and nutritional strategies recommended for patients who are good candidates for the AS approach. Even if you do not have prostate cancer, these same strategies can be endorsed as part of a comprehensive prevention plan for prostate cancer. After all, the best strategy is to prevent prostate cancer in the first place.
Tip #1: Choose your fats wisely.
A high fat diet, especially one that is high in saturated fats, is a key risk factor for prostate cancer. Saturated fats are predominately found in animal foods, such as dairy products and meats. Fats are not the enemy as long as you choose healthy fats, particularly omega-3’s. In fact, omega-3 polyunsaturated fats are cancer-protective. Good sources of omega-3 include flax oil and cold-water fish. Aim to consume fish 3x/wk. If you consume red meat, choose grass-fed over corn-fed and processed meats. The latter is high in saturated fats, while grass-fed beef is higher in omega-3 and omega-6 polyunsaturated fats.1
Tip #2: Mind your blood-sugar levels.
Every food and food combination has a “glycemic impact”, which indicates the subsequent rise in blood sugar after you eat a snack or meal. Refined grains, fruit juices, soft drinks and sugar all have high glycemic impact, which raise your blood sugar. The prostate is particularly sensitive to a growth-stimulating effects of IGF-1 (insulin growth factor – 1). A high-glycemic diet will increase IGF-1 levels in the body, while a low-glycemic diet will reduce IGF-1. Follow a low-glycemic diet by adopting a macronutrient approach to food selection: every meal, make sure you’ve got each of the following on your plate2:
Complex carbohydrate (25% of your meal): such as brown rice, millet, quinoa, yam, squash or legumes
Protein (25% of your meal): fish, chicken, grass-feed meat, free-range egg, legumes or seeds (pumpkin seeds and hemp seeds are a great source of plant protein)
Fibre (40% of your meal): vegetables such as kale, broccoli, spinach, collard greens, cauliflower, carrots, bok choy, cabbage or a salad of mixed greens and romaine lettuce
Healthy fat (10% of your meal): oils such as flax seed oil, hemp oil, grapeseed oil, olive oil or nuts and seeds such as flax seeds, hemp seeds, pumpkin seeds, sunflower seeds, walnuts3, almonds, pecans and hazelnuts.
Tip #3: Maintain a healthy body composition.
Yes, this means exercise! Find a physical activity you love to do and make it part of your daily routine, preferably 30-45 minutes a day. To maintain muscle mass, strength training should be a part of your exercise routine. To reduce fat mass, you need cardio and strength training together. The lower your fat mass, the less chance of converting testosterone to estrogen. Estrogen promotes inflammation in the prostate, increasing cell proliferation, which can lead to cancer. Ultimately, a healthy diet (see tip #3 above) and routine exercise go hand-in-hand – you need both to achieve and maintain a healthy body composition.4
Tip #4: Check your vitamin D levels annually.
Several studies show that men who are diagnosed with prostate cancer in the summer-autumn seasons are more likely to survive than men diagnosed in the winter-spring season….does this have anything to do with vitamin D levels? Quite possibly. Get your serum vitamin D levels checked in the fall. If your levels are low (< 50 ng/mL), supplement accordingly with vitamin D3.5
Tip #5: Consume 2 tbsp of flax seeds daily.
The lignans in flax inhibit the development and growth of prostate tumors, presumably by binding xenobiotics (estrogen and estrogen-mimicking agents) in the stool. The extra fibre from flax seeds also helps maintain bowel regularity, supporting the elimination of toxins from the body.
Following these tips may not guarantee that you won’t get prostate cancer in your lifetime (note: many men will develop indolent, slow-growing prostate cancer but will not die from it), but it will reduce your chances of developing invasive prostate cancer – the type that can shorten your lifespan and have significant impact on your health.6
Tip #6: Replace dairy products with soy.
Soy you say? Although this may come as a surprise to most, higher soy consumption and lower dairy consumption has been associated with lower rates of prostate cancer. Epidemiological studies report a markedly lower incidence of prostate cancer in Asian countries, which may be attributable to the prevalence of soy-based foods in a traditionally Asian diet.7 Soy products contain a compound called genestein, which has been shown in animal studies to inhibit the growth and spread of prostatic tumors.8
Tip #7: Consume Green Tea
Green tea contains an anti-cancer compound known as epigallocatechin gallate (or EGCG for short). Numerous studies have demonstrated the value of EGCG as an anti-inflammatory, pro-apoptotic (promotes cancer cell killing), and anti-oxidant cancer preventive agent.9 To obtain the anti-cancer benefits from green tea, consume 5-6 cups, preferably in the earlier part of the day so that the caffeine content doesn’t interfere with your sleep. Green tea not quite your cup of tea? You can also opt for high-quality EGCG in a supplement form.
1. Rosato V, Edefonti V, et al. Nutrient-based dietary patterns and prostate cancer risk: a case-control study from Italy. Cancer Causes Control. 2014 Apr;25(4):525-32. doi: 10.1007/s10552-014-0356-8.
2. Kim H, Yokoyama W, et al. TRAMP Prostate Tumor Growth Is Slowed by Walnut Diets Through Altered IGF-1 Levels, Energy Pathways, and Cholesterol Metabolism. J Med Food. 2014, Oct 29.
3. Cao Y, Nimptsch K, et al. Prediagnostic plasma IGFBP-1, IGF-1 and risk of prostate cancer. Int J Cancer. 2014, Oct 27.
4. Antonelli JA, Jones LW, et al. Exercise and prostate cancer risk in a cohort of veterans undergoing prostate needle biopsy. J Urol. 2009 Nov;182(5):2226-31. doi: 10.1016/j.juro.2009.07.028.
5. Weinstein S, Mondul Alison, et al. Circulating 25-hydroxyvitamin D, vitamin D-binding protein and risk of prostate cancer. Int J Cancer. June 2013, 132(12): 2940-2947. doi:10.1002/ijc.27969.
6. Azrad M, Vollmer RT, et al. Flaxseed-Derived Enterolactone Is Inversely Associated with Tumor Cell Proliferation in Men with Localized Prostate Cancer. Journal of Medicinal Food. April 2013, 16(4): 357-360. doi:10.1089/jmf.2012.0159.
7. Cheetham P. J., Katz A. E. Diet and prostate cancer—a holistic approach to management.Archivos Espanoles de Urologia. 2011;64(8):720–735.
8. Rose D. P., Boyar A. P., Wynder E. L. International comparisons of mortality rates for cancer of the breast, ovary, prostate, and colon, and per capita food consumption. Cancer. 1986;58(11):2363–2371.
9. Johnson J. J., Bailey H. H., Mukhtar H. Green tea polyphenols for prostate cancer chemoprevention: a translational perspective. Phytomedicine. 2010;17(1):3–13.