To Your Health June, 2016 (Vol. 10, Issue 06)

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Why All Men Should Go Vegan

By James P. Meschino, DC, MS

Finding from a large study published in January 2016 in the American Journal of Clinical Nutrition demonstrated that vegan men had a 35 percent lower risk of developing prostate cancer compared to non-vegan men.

This was especially true for white males, with a similar trend for black male vegans, although the association was not quite as strong.¹ The study followed more than 26,346 men who are part of the Adventists Health Study-2.

Why It Makes Sense

A number of previous studies have shown that a high intake of animal fat from beef, pork and dairy products and/or saturated fat is associated with an increased risk for prostate cancer; as is a high intake of trans-fats and total fat, and the presence of obesity. The evidence also shows that a higher intake of omega-3 fats potentially has a protective effect against prostate cancer.²

In addition, various plant-based foods, generally considered main features of a vegan diet, contain known cancer-protective constituents – many of which have been shown to inhibit the development of prostate cancer in experimental studies, and some of which have been used in human clinical trials as successful adjuncts to slow or reverse cancer progression in men with established prostate cancer or precancerous lesions within the prostate.

Plant Protection

Here are some examples of plant-based foods with anti-cancer constituents shown to inhibit the development and/or progression of cancer:

Cruciferous vegetables (broccoli, Brussels sprouts, cabbage, cauliflower, bok choy) contain the anti-cancer indole-3 carbinol and sulforaphanes, which exhibit multimodal anti-cancer effects with respect to prostate cancer and other cancers.³

Tomatoes contain the carotene known as lycopene, which demonstrates multimodal anti-cancer effects against prostate cancer, and has been used in clinical studies to slow or reverse the progression of localized prostate cancer in human studies.^4-5

Soy beans / soy products – Soy beans contain isoflavones and the Bowman-Birk protease inhibitor, which exhibit multimodal anti-cancer effects in prostate cancer research. Soy isoflavone supplements have also been used to slow / reverse the progression of localized prostate cancer in human clinical studies.⁶

Peas and beans contain lignins, phytates and protease inhibitors, which exhibit various anti-cancer properties.⁷

Green tea – The catechins (polyphenols) in green tea demonstrate impressive anti-cancer properties in regard to prostate cancer and other cancers. Thus far, two human clinical studies have shown the ability of green tea catechin supplementation to prevent the progression of precancerous prostate lesions, while a human clinical study suggests the ability to improve the management of localized prostate cancer.^8-9

Pomegranate juice – Pure pomegranate juice contains ellagic acid, which is an important anti-cancer constituent. Two human prostate cancer studies have shown the ability of 8 ounces of pure pomegranate juice per day to help improve management (lowering the PSA level) in advanced cases of prostate cancer.¹⁰

Ground flaxseed contains the precursors to enterolactone and enterodiol, which are unique phytoestrogens. These agents have been shown to slow the proliferation of prostate cells and the replication of prostate cancer cells in men awaiting prostate cancer surgery.¹¹

What It Means to You

The results of the Adventists Health Study-2 provide additional support to the body of evidence showing specific plant foods contain important anti-cancer nutrients that offer protection against prostate cancer. Equally important is the avoidance of high animal fats rich in saturated fat and overconsumption of trans-fats. As prostate cancer accounts for 27 percent of all male cancers and is the second leading cause of cancer death in men in our society,¹ I believe it is important for men to appreciate these findings and adopt these protective lifestyle modifications.

It's unrealistic to think all men are going to switch to a vegan diet, but consuming leaner animal products (chicken and turkey breast; low-fat dairy products) that contain less saturated fat, cutting out deep-fried foods and reducing other sources of trans-fats, while regularly including plant-based foods that contain proven anti-prostate-cancer constituents, appears to be a prudent and practical prostate-prevention diet and lifestyle plan.

References

1. Tantamango-Bartley T, Knutsen SF, Knutsen R, et al. Are strict vegetarians protected against prostate cancer? Am J Clin Nutr, 2016;103(1):153-160.
2. Di Sebastiano KM, Mourtzakis M. The role of dietary fat throughout the prostate trajectory. Nutrients, 2014; 6:6095-6109.
3. Dhinmi SR, Li Y, Upadhyay S, Koppolu PK, Sarkar FH. Indole-3-carbinol-induced cell growth inhibition, G1 cell cycle arrest and apoptosis in prostate cancer cells. Oncogene, 2001;20(23):2927-36.
4. Vaishampayan U, Hussain M, Seren S, Sarkar F, Fontana J, et al. Lycopene and soy isoflavones in the treatment of prostate cancer. Nutr and Cancer, 2007;59(1):1-7.
5. Matlaga BR, Hall MC, Stindt D, Torti FM. Response of hormone refractory prostate cancer to lycopene. J Urol, 2001;166:613.
6. Hussain M, Banerjee M, Sarkar FH, et al. Soy isoflavones in the treatment of prostate cancer. Nutr and Cancer, 2003;42;(2):111-117.
7. Magee PJ, et al. Chickpea (Cicer arietinum) and other plant-derived protease inhibitor concentrates inhibit breast and prostate cancer cell proliferation in vitro. Nutr and Cancer, 2012;64(5):741-748
8. McLarty J, Bigelow R, Smith M, et al. Tea polyphenols decrease serum levels of prostate-specific antigen, hepatocyte growth factor, and vascular endothelial growth factor in prostate cancer patients and inhibit production of hepatocyte growth factor and vascular endothelial growth factor in vitro. Cancer Prev Res J, 2009;2:673.
9. Bettuzzi S, Brausi M, Rizzi F, et al. Chemoprevention of human prostate cancer by oral administration of green tea catechins in volunteers with high-grade prostate intraepithelial neoplasia: a preliminary report from a one-year proof-of-principle study. Cancer Res, 2006;66:1234.
10. Pantuck J, et al. Long term follow up of phase 2 study of pomegranate juice for men with prostate cancer shows durable prolongation of PSA doubling time. J Urol, 2009;181(4):295.
11. Demark-Wahnefried W. Flaxseed supplementation (not dietary fat restriction) reduces prostate cancer proliferation rates in men presurgery. Cancer Epidemiol Biomarkers Prev, 2008;17(12):3577-87.

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James Meschino, DC, MS, practices in Toronto, Ontario, Canada and is the author of four nutrition books, including The Meschino Optimal Living Program and Break the Weight Loss Barrier.