Food – Large Intestines

This month we will look at the anatomy and function of the large intestine (colon), two common colon problems and what we can do to prevent these problems.

The large intestine is much different in size, appearance, and function from the small intestine. The colon is approximately 2.5 inches in diameter, is 5–6 feet long, is located in the abdomen and surrounds the small intestines on three sides. It is divided into six sections. The ascending colon lies on the right side of the abdomen and moves upward toward the waistline. The transverse colon moves across the upper abdomen from the right side to the left side. The descending colon moves downward to the lower abdomen on the left side. The sigmoid colon is “S” shaped and moves into the pelvis. It connects to the rectum and ends in the anal canal from which our waste products exit the body.

The main functions of the colon are to absorb water from the food mass from the small intestine and to eliminate the remaining waste from the body. Two other functions of the colon relate to the bacterial flora within the colon. The bacterial flora interacts with the fiber in the colon, causing fermentation, release of irritating acids, and formation of gas. In addition to this, the bacterial flora makes B-complex vitamins and most of the vitamin K required by the liver.

Constipation is the most common gastrointestinal complaint in the United States, resulting in about 2 million annual visits to the doctor. Most people, however, treat themselves to the tune of $725 million spent by Americans on laxatives each year. Approximately 17% of Americans, one in six, suffer with constipation, and 30% to 40% of Americans over 65 cite constipation as a problem.

Constipation means different things to different people, but common criteria for constipation is if you have two or more of the following for at least 3 months:

Straining during a bowel movement more than 25% of the time.

Hard stools more than 25% of the time.

Incomplete evacuation more than 25% of the time.

Two or fewer bowel movements in a week. Note: the more common and healthful bowel pattern is one movement a day, but this pattern is seen in less than 50% of people.

Constipation is a symptom, not a disease. Understanding its causes, prevention, and treatment will help most people find relief. A poor diet, low in fiber, is often the cause. Inadequate intake of water also contributes to constipation, as does a sedentary lifestyle. Most constipation is temporary and not serious.

Colon cancer, a prevalent disease of the large intestines, is very serious. In 2008, it is estimated that over 100,000 new cases of colon cancer will be diagnosed with nearly 50,000 deaths. Numerous factors contribute to colon cancer, many of which we can prevent or avoid. Associated with increased incidence is alcohol consumption, diabetes, a diet high in fat and low in fiber, lack of exercise, obesity, more than 2 meals a day, and smoking. Incidence is also increased with age over 50, a close family history of colon cancer, and presence of polyps.