PLANT-BASED DIETS AND CANCER PREVENTION March 11, 2015 11:41

So another study was released today showing a correlation between a plant-based diet (vegetarian in this case) and cancer prevention.   We’ve all seen a lot of these and in this post, we’re going to talk about what all of these studies and findings have in common and why this may be the case, some of the ways they’ve been applied, and (of course) our take on the whole thing.

So, what do these studies and findings have in common?  Over and over again, we see results showing that people who eat more fruits and vegetables and other whole foods and less animal products and processed foods get cancer less often and have better results once they have the disease.  (The same is also true for heart disease, diabetes, and just about any other disease prevalent primarily in first world societies.)  So what drives this connection?  Well, there are lots of theories and they vary by study and by type of cancer.  Generally speaking (and this is definitely a simplification), our bodies our exposed to all sorts of toxins on a daily basis than can potentially cause our cells to mutate and become precancerous– this has caused some people to feel they should just give up because “everything causes cancer.” Additionally, some of us also have a genetic predisposition for certain types of cancer. 

But we were talking about the role diet plays; if we are all exposed to these toxins, and genetics play a role too, how can a plant-based diet help?  There are several stages of cancer, with two phases (which can last for years) taking place before cancer is evident.  The first phase is the actual cell mutation described above.  We may not have a lot of control over that part given the world we live in.  But the second phase (called promotion) is a long phase, and it’s where our behavior (including factors like diet and stress) come into play.  If the cancer is not reversed in this promotion phase, the cancer becomes clinically evident and we move into metastasis.  Many studies (including the one referenced at the top) have shown the correlation between a plant-based diet and lower incidences of cancer.  Other studies (referenced at end) have shown that for various reasons a plant-based diet has a significant impact, specifically during the promotion phase.  Nutritional differences don’t stop the cells from mutating, but it does apparently impact our bodies’ ability to stop these cells from taking hold and multiplying.   If you’ve heard people say that sugar feeds cancer – this is what they are referring to.

These various studies have focused on a variety of factors.  Some show that it’s the fiber that leads to less cancer.  Some indicate lower levels of protein, especially animal protein. Some focus on phyto-nutrients.   Others (like the one linked at the top) just focus on the correlation and don’t draw any conclusions about why.  But here’s a thought – does it really matter?  Because they all point to plants being better for preventing cancer than animal based food.

So when we read something like this: ”It's not known whether there is something in vegetables that is protective or whether something in meat is harmful…” as we do in this same article, that’s our reaction – does it really matter?  Given all of the evidence out there, doesn’t it make sense to eat more plants and less processed foods and animal foods?

Examples of studies and summaries of studies:

Messina V, Burke K. Position of the American Dietetic Association: Vegetarian Diets. Journal of the American Dietetic Association 1997;97:1371-21.

Steinmetz K, Potter J. Vegetables, fruit, and cancer, I. Epidemiology. Cancer Causes Control1991;2(suppl):325-57.

Jacobs DR, Marquart L, Slavin J, et al. Whole-grain intake and cancer: an expanded review and meta-analysis. Nutr Cancer 1998;30:85-96.

Divisi D, et al. Diet and cancer. Acta Biomed. 2006 Aug;77(2):118-23.

Nguyen JY, et al. Adoption of a plant-based diet by patients with recurrent prostate cancer. Integr Cancer Ther. 2006 Sep;5(3):214-23.

Saxe, GA, et al. Potential attenuation of disease progression in recurrent prostate cancer with plant-based diet and stress reduction. Integr Cancer Ther. 2006 Sep;5(3):206-13.

Madhavan TC and Gopalan C. “The effect of dietary protein on carcinogenesis of aflatoxin.” Arch. Path. 85(1968): 133-137

Youngman LD, and Campbell TC. “High protein intake promotes the growth of preneoplastic foci in Fischer #344 rats: evidence that early remodeled foci retain the potential for future growth,” J. Nutr. 121 (1991)