Monday, June 11, 2012

Forks Over Knives Part 2: Examining the Validity of Scientific Studies

In the beginning, Dr. Islas gave us a short list of lifestyle changes that could be made to combat or slow the onset of cancer. Wear sunscreen. Exercise. Avoid smoking. Eat Healthy.  In a 2011 American documentary directed by Lee Fulkerson, this idea of eating healthy as a means to combat degenerative diseases and reverse the growth of cancerous cells is explored through promotion of a “Whole Foods Plant Based Diet” while simultaneously reviewing the works of American physician Caldwell Esselstyn and professor of nutritional biochemistry T. Colin Campbell, two of the most prominent advocates for the diet in America. (You may remember this from the blog post “Forks Over Knives: How a Whole Foods Plant Based Diet Can Cure You”).
In response to the documentary, I asked for the general thoughts and opinions of the class on the evidence presented and if you would consider the whole foods plant based diet. Well, since I did not note a significant rise in veganism on campus I would venture to guess that most of you still do not think of milk protein as a carcinogen and animal based proteins are still a staple in the majority of your diets, skeptical of the claims that a whole foods plant based diet can cure all ailments and prevent cancer. You are justified in your skepticism.

Upon further examination of Campbell’s experiment, which manipulated the diets of lab rats through moderation of the protein casein which is found in milk, there are a few holes to be investigated within the conclusions. In “Forks over Knives,” Campbell explains his experiment simply, stating that half the lab rats he tested were given a diet of 20% casein, and the remaining half were given a diet of 5% casein (after exposure to a carcinogen). His results concluded that the rats consuming greater amounts of casein had greatly enhanced liver cancer tumor growth while the rats consuming less of the animal-based protein showed no incidence of tumor growth at all.

 What is neglected here, however, is the duration of the study, the population size, and the overall health of the lab rats. It is in these that the other half of the discussion comes into play. In an examination of the document that had inspired Campbell, an article in an Indian medical journal which detailed the casein experiment Campbell would later replicate, it can be noted that the experiment ended prematurely due to the high mortality rates of the rats. “In all, 30 rats on the [high protein] diet and 12 rats on the [low protein] diet survived for more than a year.” In essence, the low protein rats were dying too rapidly; they never had an opportunity to fully develop cancer.  

In “The Curious Case of Cambell's Rats,” Chris Masterjohn examines these rats that Campbell used, describing their severe protein deficiency and  inability to thrive despite their apparent health and lack of cancer. The low protein group of rats “[ate] less food, [failed] to grow, and [were] unable to efficiently detoxify aflatoxin and a multitude of other toxins. They destroyed their ability to repair damaged tissue, gave them fatty liver, stopped their internal organs from developing, and if the rats encountered toxic substances, the diets dug them an early grave” (Masterjohn). Expecting that the rats on a low protein diet would consume less than those receiving relatively high amounts of protein, Campbell broke his rats into three groups: 5% casein, 20% casein, and 20% casein pair fed with the 5% group. The rats, who were still in their developmental and growing stages at the time of the experiment start, were expected to grow to over 100g in size before the conclusion of the experiment. Their growth is seen below.

The rats restricted to a low protein diet achieved less than half of their expected growth.

Beyond a mere failure to grow, the rats restricted to a low protein diet developed fatty livers, which was suggested to have been a result of disruption of cell proliferation or a disruption of protein synthesis. The rats on a low protein diet were also more susceptible to environmental toxins when compared with the high protein rats, an observation which may indicate the low protein diet was not sufficient for the promotion of tissue recovery from toxic effects.  These findings on toxic effects are further distorted by the quantity of aflatoxin administered to the rats as a carcinogen. The high protein rats were administered double the amount of aflatoxin administered to the low protein rats, receiving 5 parts per million (ppm) in comparison to 2.5 ppm. This discrepancy in carcinogen doses is explained by Campbell in his book, The China Study, as necessary because “5ppm was found to be lethal for [the low protein] dietary group” (Campbell).  The cancer promoting effects of a high casein diet could be the result of a lack of consistency in carcinogen administration.

So what are we to think now? Should we all adopt a whole foods plant based diet in order to stay healthy and continue the war on cancer? Is our diet really what’s killing us? The documentary presented many testimonials of people who adopted this lifestyle of plant-based nutrition and no longer required their medications for conditions like hypertension, type II diabetes, or even cancer, but as I have just commented on, the presentation of data is the key. In this post I explored only one of the experiments cited in the documentary and exposed the unfavorable results the producers apparently forgot. It is true that the low protein rats developed less tumors and showed fewer signs of cancer, but cancer is only one part of the story, only one disease that will kill us before we reach the Hayflick limit.

What are your thoughts now?    


"“Forks Over Knives”: Is the Science Legit? (A Review and Critique)." Raw Foods SOS: Rescuing Helath Food from Bad Science. Raw Foods SOS, 22 Sep 2011. Web. 11 Jun 2012. <>.

Fulkerson , Lee, dir. Forks Over Knives. "“Forks Over Knives”: Is the Science Legit? (A Review and Critique)." Raw Foods SOS: Rescuing Helath Food from Bad Science. Raw Foods SOS, 22 Sep 2011. Web. 11 Jun 2012. . , 2011. Film.

Masterjohn, Chris. "The Curious Case of Cambell's Rats." Weston A Price Blogs. Weston A Price Foundation, 22 Sep 2010. Web. 11 Jun 2012. <>.