Topic summary contributed by volunteer(s): Linda

Colon cancer is the second-leading cause of cancer death in the United States, behind lung cancer.  At least 70% of colon cancer cases are avoidable. Numerous studies suggest that a plant-based diet may be beneficial in the prevention, treatment, and even reversal of cancer.

What may contribute to colon cancer?

Heterocyclic amines, carcinogens created by cooking muscle tissue, are associated with colon cancer, as are dangerous compounds called nitrosamines found in cured meats. Too much iron in the body, especially the type of iron that comes from meat, may also increase the risk of colon cancer. Animal protein consumption is associated with an increase in a cancer-promoting growth hormone called IGF-1. High saturated fat from animal products stimulates elevated levels of bile acids, which have been shown to be cancer-causing. When animal protein putrefies in the colon, ammonia is produced, which is associated with cancer risk. Poultry and other animal products contain viruses that are known to cause cancer in animals and may be passed to humans. Additionally, dioxins in fish and eggs may contribute to colon cancer risk.

What may help prevent colon cancer?

The rarity of colon cancer in Africans is attributable to very low animal-product consumption. The significantly lower pH in the colon resulting from a plant-based diet helps lower the risk of colon cancer. Specific protective foods include beans, berries (including Indian gooseberries and organic strawberries), broccoli, black beans, a number of herbal varieties of tea, carob, coffee, apples, turmeric, cranberries, sweet potatoes, nuts, and lemon rind and seeds. Vitamin D may also play a role in preventing colon cancer. The kind of “resistant starch” that comes from plant foods like cooked beans, peas, lentils, and raw oatmeal—can block the accumulation of potentially harmful byproducts of animal-protein metabolism in the colon. 

Stool size may be an important factor in colon cancer prevention. A plant-based diet produces the healthiest stools, and leads to consistently larger bowel movements.

For substantiation of any statements of fact from the peer-reviewed medical literature, please see the associated videos below.

Image Credit: Internet Archive Book Images / Flickr. This image has been modified.