Chapter 10. Colon Cancer

“Adopting a diet that is low in fat and high in fiber, fruits, and vegetables does not influence the risk of recurrence of colorectal adenomas.”
The New England Journal of Medicine [1]

Dietary Fiber: Naturally Grown Killer

Okay, so fiber isn’t good for constipation and it causes all kinds of nasty, but not yet deadly problems. But what about colon cancer? Aren’t we getting rid of one plague (fiber), to gain another (cancer)?

That’s an excellent and appropriate question. And I’m the last person to encourage you to play Russian roulette. So let’s check out the odds.

Colorectal cancer and dietary fiber

The question whether dietary fiber contributes to colorectal cancer has (at least for me) been answered time and again—yes, it absolutely does. But this isn’t what you’ve probably heard before, or are likely to accept on faith alone. So let’s review this issue in greater depth. Undoubtedly, it will come up again and again in your discussions with doctors, relatives, and peers, and you’ll need all the armor you can find to deflect the onslaught of ignorance, misinformation, and outright falsehoods.

The term colorectal cancer refers to cancers of the colon and the rectum. In general, surgery to remove colon cancer causes less damage than surgery for rectal cancer, because the latter almost always involves removing an entire important organ (the rectum), while with colon cancer, if there’s no metastasis, only a section of the colon is removed so that the normal defecation remains functional.

There are also three somewhat confusing terms used in relation to colorectal cancers: colorectal carcinoma, adenoma, and adenocarcinoma. Technically, carcinoma refers to malignant tumors, while adenoma to benign. That said, colorectal adenomas and carcinomas present physicians with similar risk profiles, hence you’ll frequently hear the term colorectal adenocarcinoma. In either case, surgery is required to remove the intestinal obstruction caused by the tumor, and to halt further spread of the cancer.

The actual nature of the tumor is established by a pathologist from the biopsy sample taken before the surgery, or from a post-surgical tissue sample. In general, when communicating with patients most doctors refer to carcinomas and adenomas interchangeably (colorectal cancer or adenocarcinoma,) because they themselves may not know the distinction until the pathology report.

In medical literature you may encounter yet another, even broader term that specialists use among themselves: a neoplasm. It simply means an abnormal growth of tissue mass, which is dif­ferent from regular tissue, and may be either benign or malig­nant. Anything abnormal—adenoma, carcinoma, sarcoma (connec­tive tissue malignancy) is therefore a neoplasm. The rest of this chapter uses the term colorectal cancer, which for clarity’s sake encompasses all other meanings and definitions.

It’s a well-established fact that most colorectal cancers are preceded by the formation of precancerous polyps—cellular growths that visibly protrude from the mucous lining of the large intestine. Therefore, anything that can cause temporary or permanent damage to the mucous lining is capable of causing the growth of po­lyps, that eventually may become tumors.

The terms polyp is actually an euphemism for tumor and neoplasm. Don’t kid yourself over the issue of early detection—you should be more concerned about preventing the polyps from developing in the first place, rather than hoping that regular colonoscopies will make you safe. Unless you remove the causes of these polyps, colonoscopies aren’t going to save, quite literally, your butt. Thinking otherwise is very profitable for medical sector, but in practical terms, this “prevention” approach is as asinine as putting out fires with gasoline.

So what should you do to prevent polyps?

Protect yourself from harm. The mucosa damage that precedes the appearance of polyps can be (a) mechanical (a cut or abrasion), (b) chemical (caused by an irritant, such as laxatives, fatty acids, bile, etc), (c) viral or bacterial, or (d) a combination of all these factors. Just as with any other organ, the mucosa react with inflammation to superficial injury, or with ulceration and bleeding if the exposure is long-lasting and unrelenting. Can this be from an exposure to fiber? Well, let’s think aloud:

• If a substance increases the stool’s size and volume five-to-six times and causes permanent stretching, diverticulosis, diverticulitis, hemorrhoids, and anal fissures, then this substance also has the potential to cause mechanical damage to the incomparably more delicate mucosa inside the large intestine, and stimulate the growth of precancerous polyps.
• If a substance causes bacterial fermentation inside the large intestine, leading to the production of highly irritating fatty acids, which may cause diarrhea and ulcerative colitis, or even itching in the anus, then this substance can also cause chemical damage of the mucosa, leading to the formation of polyps.

So what is this substance that can cause both mechanical and chemical damage of the intestinal mucosa? There is only one such substance in the daily diet of most Westerners—dietary fiber that reaches the gut undigested.

• Can it be meat? No, it can’t, because meat, any kind of meat, digests completely inside the functioning stomach, and never reaches the large intestine.
• Can it be saturated fat? No, it can’t, because saturated fats get digested and absorbed almost completely inside the functional small intestine, and never reach the large intestine.
• Can it be digestible carbohydrates? No, not directly, because digestible carbohydrates too, never reach the large intestine—they digest completely inside the healthy small intestine, and get absorbed there as well. Indirectly—well, it’s a different story.

It’s apparent that nothing but indigestible dietary fiber, whatever the source, can cause mechanical damage either directly or indirectly, by means of the by-products of bacterial fermentation.

But there’s a bit more to it. The majority of indigestible fiber comes in the nice wrapping of digestible carbohydrates—those proverbial fruits, vegetables, breads, pasta, and cereals, whose ten to fifteen servings you’re supposed to consume daily to stay healthy: