Much more has been written about dietary prevention of prostate cancer than about what to do after a diagnosis of prostate cancer. The approaches could very well be similar. However, in this small summary, I’ll look mainly at dietary approaches post prostate cancer diagnosis.
Somewhat oddly in my view, most of the dietary prevention research and summary seems to have concentrated on individual dietary components and supplements therof. The main players in prostate cancer prevention have been the minerals selenium and zinc, vitamin E and lycopene (an antioxidant from tomatoes and red-coloured plants). Most of the ongoing evaluations of these nutrients in prostate cancer prevention have not resulted in much clarification or success. Vitamin D status has also received quite a bit of attention, but results and prospects for manipulation of levels above normal ranges for prostate cancer prevention do no seem promising either according to a recent journal summary.
In a general terms, the high-fat, red and processed meat, sugar and dairy western type dietary pattern seems to carry most risk — especially when associated with obesity — compared to diets high in plant foods, however you want to define that .
Diets After Prostate Cancer Diagnosis
Most of the work in dietary approaches to post-diagnosis of prostate cancer has been done by Aronsen, Barnard and Freeland at al. This approach favours high plant-food diets low in fat (under 15%), high fibre, low-refined CHO and sugars, increased plant estrogens including soy, low in red meat and saturated and polyunsaturated fats, higher in omega-3. Some of this work has seen a drop in PSA (prostate specific antigen), a diminution of PSA progression index, and, or amelioration of cancer growth factors. For example:
Aronson WJ, Barnard RJ, Freedland SJ, Henning S, Elashoff D, Jardack PM, Cohen P, Heber D, Kobayashi N. Growth inhibitory effect of low fat diet on prostate cancer cells: results of a prospective, randomized dietary intervention trial in men with prostate cancer. J Urol. 2010 Jan;183(1):345-50.
CONCLUSIONS: In this prospective, randomized dietary intervention trial a low-fat diet resulted in changes in serum fatty acid levels that were associated with decreased human LNCaP cancer cell growth. Further prospective trials are indicated to evaluate the potential of low fat diets for prostate cancer prevention and treatment.
Freedland SJ, Aronson WJ. Dietary intervention strategies to modulate prostate cancer risk and prognosis. Curr Opin Urol. 2009 May;19(3):263-7. Review. SUMMARY: Small clinical trials suggest that tumor biology can be altered by either a vegan low-fat diet or eliminating simple carbohydrates accompanied by weight loss. Larger and longer term studies are needed to determine the clinical relevance of these findings.
Dewell A, Weidner G, Sumner MD, Chi CS, Ornish D. A very-low-fat vegan diet increases intake of protective dietary factors and decreases intake of pathogenic dietary factors. J Am Diet Assoc. 2008 Feb;108(2):347-56.
Li Z, Aronson WJ, Arteaga JR, Hong K, Thames G, Henning SM, Liu W, Elashoff R, Ashley JM, Heber D. Feasibility of a low-fat/high-fiber diet intervention with soy supplementation in prostate cancer patients after prostatectomy. Eur J Clin Nutr. 2008 Apr;62(4):526-36.
CONCLUSION: These data suggest that long-term low-fat dietary interventions as part of prospective randomized trials in prostate cancer survivors are feasible, and lead to reductions in circulating hormones or other growth factors stimulating prostate cancer growth ex vivo.
There is also:
Demark-Wahnefried W, Polascik TJ, George SL, Switzer BR, et al. Flaxseed supplementation (not dietary fat restriction) reduces prostate cancer proliferation rates in men presurgery. Cancer Epidemiol Biomarkers Prev. 2008 Dec;17(12):3577-87.
CONCLUSIONS: Findings suggest that flaxseed is safe and associated with biological alterations that may be protective for prostate cancer. Data also further support low-fat diets to manage serum cholesterol.
However, there is enough earlier work to suggest that intake of alpha-linolenic acid (plant form of omega-3s in flax and other things) is associated positively with prostate cancer. This may be an anomaly, but it’s ‘wait and see time’ for that idea, for me.
Summing up, for prevention of prostate cancer you probably can’t go past general healthy eating and activity recommendations — plenty of plant foods and only modest amounts of meat and saturated fat and dairy, and the maintenance of normal weight and plenty of exercise. Post-diagnosis, a diet high plant foods, low in fat, especially saturated and polyunsaturated, with liberal serves of phytoestrogens in foods like soy, appear to produce promising results.