Paying attention to the colon
Think of eating and digesting as a series of dramatic actions, a storm of activity, going on inside your gastrointestinal tract. Food is positioned by the tongue so it can be chewed into something that will fit into the esophagus. Muscles in that 10-inch tube contract in a symmetrical downward action, called peristalsis, to propel the food into the stomach.
There the food is awash in a caustic concoction of gastric juices — corrosive stomach acids that break down everything they touch, and highly targeted enzymes that attack specific substances. Powerful stomach muscles churn the food until it is a creamy liquid, which moves through the pyloric valve into the small intestine. Here the food particles get even smaller, as a potent mix of juices from the pancreas, liver, and gallbladder go to work. The food continues forward, again through peristalsis, as vital vitamins and nutrients begin to move into the blood vessels. The blood then carries these nutrients throughout the body to repair cells and tissue.
What is left, mostly liquid, moves into the colon. Here the water is absorbed. Bacteria tackle the remaining material as the colon moves it forward, again with peristaltic action, compacts it, and delivers it to the rectum where it is stored until it’s time for the muscles in the rectum to expel this waist, now called stool, out of your body.
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The size of the intestines that produce all this lively activity can vary with the individual. The Cleveland Clinic puts the small intestine at approximately 22 feet, and the colon or large intestine at about 6 feet. Though shorter in length, the colon is much larger in diameter and surrounds the coils of the small intestine. It has four parts — the ascending colon, the transverse colon, the descending colon, and the sigmoid colon (see the diagram).
No part of the gastrointestinal tract is more important than another, and we need each part to work well to be healthy, but this 6-foot muscular tube called the colon, whose job is elimination, is crucial to our health and comfort. There are many things that can go wrong.
The condition we hear the most about is
colon cancer
. This afflicts more than 100,000 Americans each year. It starts with small noncancerous polyps, which over time can become cancerous. Regular colonoscopies (where a long tube with a tiny light and camera at its tip is used to check the colon interior) are vital for detecting and removing these polyps before they become malignant. It is not clear what causes colon cancer, but genetics seem to play a part.
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Irritable bowel syndrome, or IBS,
is a common disorder of the colon. Symptoms include cramping, abdominal pain, bloating, gas, and also diarrhea and constipation. It is a chronic condition and must be managed by diet, lifestyle changes, and reduction of stress. IBS is not known to cause changes in bowel tissue or increase the risk of colon cancer.
IBS should not be confused with
inflammatory bowel disease, or IBD
, which is an umbrella term for
Crohn’s disease
, an inflammatory condition affecting the colon and intestines, and
ulcerative colitis
, an inflammation of the colon and rectum. The symptoms of Crohn’s are abdominal pain and diarrhea, sometimes bloody. Bloody diarrhea is also a symptom of ulcerative colitis.
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Diverticulosis
is the presence of pea-sized diverticula or pockets in the lining of the bowel. They are common and harmless and affect 10 percent of the world’s population age 50 and younger, and 50 percent of all people by the time they reach 80. However, when diverticula grow, the intestinal walls weaken, and
diverticulitis
develops, which can cause blockage, inflammation, bacterial infection, and rectal bleeding.
Diarrhea
is maybe the most common condition of the bowels, but it also can be a symptom of a number of other conditions. Its most common causes are a virus, bacteria, or a parasite.
Several months ago,
Well Now
featured a discussion of the brain-gut axis and explored the connection between the microbiome — the billions of bacteria in the gastrointestinal tract, most of which have not yet been identified — and the brain. Through millions of neurons in the walls of the intestines, these bacteria communicate with the neurons in the brain in a process still not understood. We often hear people say they sense things with their “gut.” There seems to be no question that the activity down there can affect the way we think and feel.
Remember the famous words of Scrooge in Dickens’
Christmas Carol
when he used food-related malaise to explain the appearance of Marley’s ghost — “You may be an undigested bit of beef, a blot of mustard, a crumb of cheese, a fragment of underdone potato. There’s more of gravy than of grave about you, whatever you are!”
Whether we are considering the peristaltic action of digestion or the still-not-understood connection between activities in the gut and images in the brain, it is clear that keeping the colon healthy is vital to our gastrointestinal tract, for our overall well-being, and even as it relates to our cognition. For there may be more of gravy in our attitudes than
we realize.
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