Everyone knows someone who has or has died of cancer. There are so many different kinds of cancer, and so many potential causes, that it’s easy to get overwhelmed. When you consider the recent estimation that within the next forty years one in two men and one in three women will contract cancer, it’s even easier to throw up your hands and give in to the mysterious and terrifying threat that cancer poses.

Why bother reading the ingredients on every cleaning product in the house, why bother worrying about paint fumes, and preservatives and cell phones when new causes of cancer are being discovered every day? Even if you quit your job and moved to the woods you’d have to be careful not to bring DDT-containing bugspray and paraben-filled sunblock.

Dr. T. Colin Campbell, a foremost authority on the study of disease, has conducted over two decades of peer-reviewed research into the cause and prevention of cancer. His conclusion is simple: while a chemical may initiate the production of cancer, the damage will not spread as long as a person eats a plant-based diet, and avoids animal protein.

In his book The China Study, Dr. Campbell makes the point that, when it comes to cancer causing chemicals, the public is easily alarmed by scientific results that are not very significant. He gives the example of a study that found a 5%-10% higher incidence of cancer in rats fed astronomically high doses of NSAR, a chemical used to preserve meat. The study caused a huge public outcry and the industry was forced to cut down on its use of nitrite, the precursor to NSAR.

Dr. Campbell asks, “but what if researchers produced considerably more impressive scientific results that were far more substantial? What if there was a chemical that experimentally turned on cancer in 100% of the test animals and its relative absence limited cancer to 0% of the animals? Furthermore, what if this chemical were capable of acting in this way at routine levels of intake and not the extraordinary levels used in the NSAR experiments? Finding such a chemical would be the holy grail of cancer research.” (1)

Early on in his career, Dr. Campbell came across a study that suggested that animal protein fits this description of a chemical that promotes cancer in 100% of cases, at regular levels of intake. At the time, he was studying aflatoxin, a highly ranked carcinogen that occurs naturally in moldy peanuts. While reviewing the literature on the subject, Dr. Campbell read a study from India which found that among two groups of rats fed the same high dose of aflatoxin, every single member of the group which was fed a 20% animal protein diet contracted liver cancer, while every single member of the group which was fed a 5% animal protein diet did not contract cancer. (2)

He was suspicious of the results at first. In fact, a senior scientist scoffed at the study and said they must have mixed up the groups. All the work of nutritionists at the time was focused on finding ways to increase the availability of protein, and especially animal protein, in malnourished populations. Animal protein was considered necessary for human health, and Dr. Campbell and his colleagues believed that they were doing good work by finding ways to maximize the production of meat.

Still, he couldn’t simply turn his back on a study just because it contradicted everything he knew. The more closely he examined the results, the more he understood how important it was to understand the role of animal protein in cancer formation.

When he began his studies, very little was known about the different stages of cancer. Over the years, however, through his own research and that of his colleagues, he observed three different stages of cancer: initiation, promotion and progression. He compares these three stages to the process of growing a lawn. Initiation is when you plant the grass seeds. Promotion is when those seeds begin to grow, and progression is when the lawn grows so big that the grass starts to invade the driveway, the sidewalk and everything else around it.

It had already been established that chemicals such as NSAR or aflatoxin initiated cancer by damaging the DNA of a cell. However, Dr. Campbell demonstrated that this damage will only spread if animal protein is available. If a person modifies their diet to eliminate animal protein, cancer will not reach the stage of progression. Dr. Campbell concluded the first part of his research by observing that, “the initiation stage is far less important than the promotion stage of cancer. This is because we are very likely ‘dosed’ with a certain amount of carcinogens in our everyday lives, but whether they lead to full tumors depends on their promotion, or lack thereof.” (3)

Dr. Campbell’s findings are remarkable, practical and applicable to everyone on the planet. He is highly regarded among his peers, and his experience in the field is extensive. But still, his conclusions are not widely understood. Just this morning, I read an article that asked, “Why do we focus on the least important causes of cancer?” I clicked on it, expecting to find something about the importance of diet in cancer formation. I nodded in agreement through the beginning of the article, while the author wondered why we react with such alarm over individual chemicals while ignoring the underlying “natural” causes of cancer. In the end, however, I was surprised to read that one of the “naturally occurring” causes of cancer he was worried about wasn’t animal protein, but aflatoxin!

Certainly, trying to contain or eliminate aflatoxin, NSAR, DDT, parabens and all the other thousands of naturally occurring and man made carcinogens is a worthy goal. But in the meantime, we would be foolish to ignore Dr. Campbell’s prescription to inhibit whatever damage is already being done.


(1) T. Colin Campbell, The China Study: Startling Implications for Diet, Weight Loss and Long-Term Health (Dallas: Benbella Books, 2006), 46-47.
(2) Madhavan TV and Gopalan, C. "The effect of dietary protein on carcinogenesis of aflatoxin." Arch. Path. 85 (1968): 133-137.
(3) T. Colin Campbell, The China Study: Startling Implications for Diet, Weight Loss and Long-Term Health (Dallas: Benbella Books, 2006), 65.