Diverticulosis

Control Diverticulosis With a High-Fiber Diet

Diverticulosis, which strikes roughly half the population over the age of 65, can be controlled and possibly prevented with a high-fiber diet.

If you have diverticulosis, you are not alone. The disorder is rare below the age of 35, but increases in incidence with age, so that by the age of 65, approximately one of every two people has it. By age 85, the incidence increases to 65 percent. Although regarded as a consequence of the aging process, diverticulosis should not be placed in the category of gray hair or wrinkles. It may be prevented, as well as treated, through natural dietary means.

Definition

The term diverticulosis is derived from the word diverticulum which is a sac-like projection from the cavity of a tubular organ. Although diverticula occur in a number of organs, they are most commonly encountered in the gastrointestinal tract. By far the most frequent site of involvement is the large bowel, especially the sigmoid colon, the area just above the rectum. The term diverticulosis, therefore, has become synonymous with diverticulosis of the colon.

Development

Although the exact cause of diverticulosis is unknown, two factors are critical to the development of the disease.

First, the colon wall must contain points of weakness to allow the development of the sac-like protrusions.

The second factor in the development of colonic diverticulosis relates to the degree of pressure within the cavity of the colon, known as the intraluminal pressure. The colon, particularly the sigmoid colon, is a very active segment of the bowel. It moves either in a forward, or propulsive, motion, or in a spastic, or contractive, motion. The propulsive motion is considered normal and healthy and has little effect on the intraluminal pressure, but the overactivity of the spastic motion of the colon causes an increase in intraluminal pressure.

The volume and bulk of the colonic contents have an important influence on fecal transit time and intraluminal pressure. In the presence of high volume and bulk, the pressure within the colon is diffused, and tension on the colonic wall is reduced. Transit time through the colon is hastened and the propulsive action of the colon can efficently fulfill its function of moving the bowel contents to the rectum without an increase in pressure. If, on the other hand, bowel bulk is low, transit time is slowed, and the colon uses the pressure-building spastic type of contractions in an effort to move its contents toward the rectum and evacuation.

The significance of bowel bulk has focused attention on the role of diet in the development of diverticulosis. The importance of dietary factors has been supported by epidemiological and experimental data. Interestingly, diverticulosis was virtually unknown prior to the 20th century, and all studies indicate that its prevalence is increasing, especially in the urban areas of Western countries. An increasing incidence also is occurring in population groups that have moved from rural or less-developed regions to industrialized centers. The low incidence of diverticulosis in the less-developed countries of Africa may be explained in part by the high fiber content of the diet in those areas.

The increasing incidence of diverticulosis in the Western world has coincided with food refinement processes that have removed a large portion of the fiber and bulk from foods. The net result of this "refinement" is that reduced fecal bulk enters the colon, and, even with the absorption of water that takes place, is inadequate to distend the colon and stimulate its normal propulsive motor action. Instead, propulsive activity is replaced by spastic contractile activity as the colon attempts to empty its contents, resulting in an undesirable increase in the tension on the wall of the colon.

Studies of pressure within the colon have shown striking differences between patients with diverticulosis and healthy controls. Higher pressures are noted in the diverticulosis patients, particularly in response to the ingestion of food, to emotional stimuli, and to certain drugs, particularly those in the opiate group.

Clinical Manifestations

Most patients with diverticulosis are symptom-free; frequently, the diagnosis is unsuspected and made during the course of an examination for another purpose. However, as a result of the abnormal spasm of the sigmoid colon, some patients may have recurrent left lower quadrant abdominal pain. Constipation or alternating diarrhea and constipation may accompany the pain. Patients with these symptoms are classified as having "painful diverticular disease." The symptoms are difficult to distinguish from irritable bowel syndrome, and some authorities assert that the presence of diverticulosis is coincidental.

The potential complications of diverticulosis include bleeding, infection and perforation.

Diverticulosis is a common cause of lower gastrointestinal bleeding in patients over 50. The bleeding varies in intensity from mild to severe and usually stops spontaneously.

Diverticulitis is a term indicating infection of a diverticulum and is the most common complication of diverticulosis.

Management of Diverticulosis

No drug is consistently effective for uncomplicated diverticulosis. Although antispasmodics may decrease bowel spasm, they can produce undesirable side effects as well as a slowing of colonic transit time.

The evidence of the benefits of a high-fiber diet along with our increasing knowledge of the basic mechanisms for the development of diverticulosis, have resulted in a dramatic reversal in the recommended dietary treatment of the disease. Whereas formerly doctors emphasized the importance of a low-residue, low-roughage diet, the reverse is now true and they recommend a diet high in fiber.

Whether or not a high-fiber diet can prevent the development of diverticulosis is another question. In favor of such preventive therapy are the observations made by Burkitt and others of the very low incidence of diverticulosis in Africans with an extremely high fiber intake. Another positive piece of evidence favoring the prophylactic use of a high-fiber diet is that vegetarians, who have a significantly higher mean fiber intake than non-vegetarians, have a lower incidence of diverticulosis.

Doctors also debate the need to treat a patient with diverticulosis who is symptom-free. Those against routine treatment point out that only a small percentage of diverticulosis patients develop symptoms or complications of the disease. Some studies, however, have shown that patients who have followed a high-fiber diet have fewer complications from their diverticular disease. In addition, these patients will benefit by the other favorable actions of a high fiber intake like lowering of serum cholesterol, possible protection against colon cancer, increase of fecal excretion of fat, improvement in the diabetic state, and suppression of appetite.

High-fiber dietary treatment should be initiated in the patients with diverticulosis who have symptoms either in the form of painful diverticular disease or as a result of complications. Studies have demonstrated that such treatment will improve symptoms and prevent further attacks. Taylor and Duthie in a study conducted in England, demonstrated that one month of treatment with bran in patients with diverticulosis increased stool weight, and a further six months of treatment maintained the increase in weight and hastened bowel transit time, thereby requiring less time for the stool to pass through the colon, and significantly decreased the number and intensity of colonic spasms. Sixty percent of their patients became free of symptoms within one month, and another 15 percent was symptom-free over the next six months of treatment. They also found a decrease in abnormalities of the electrical activity of the colon.

Diverticulosis patients should be aware that effects of fiber on bowel function may require three to four weeks to appear. Amounts of fiber should be increased gradually to achieve a response. Patients who use wheat bran for the first time may complain of abdominal cramping along with a sensation of fullness and flatulence, especially if the initial amount is large.

The average daily consumption of dietary fiber in the United States is less than 25 grams. In less-developed countries such as Africa and Mexico, the intake may be as high as 60 to 90 grams per day. For therapeutic purposes, the aim should be to increase intake by about 20 grams of fiber per day, utilizing dietary sources.

Fruits, vegetables, grains and nuts are valuable sources of fiber. Cereals provide a particularly practical, convenient and concentrated source of dietary fiber in the form of wheat or oat bran. One-half cup of bran provides an average of 10 grams of dietary fiber. Remember that the word "bran" on a cereal label does not necessarily ensure an adequate fiber supply since the bran content in cereal varies. Coarse bran is much superior to fine bran as a source of fiber.

Despite the best efforts of a physician or dietician to encourage a patient to use food sources of fiber, fiber supplements may be necessary. A wide variety of products provide supplementation for food sources. Many of these contain psyllium, derived from the seed of the plantago plant. Other products use methylcellulose or bran. Because fiber supplements swell with water after ingestion and cause satiety, they are best used before meals in the obese and after meals for thinner patients.

The great advantage of fiber supplements is that they help the body to respond in a natural way. Because they enhance the body's natural response and are not absorbed, they are ideal for a patient with diverticulosis. They are also very helpful for the patient with functional constipation and in some patients with irritable bowel syndrome.

Fiber supplements are readily available in health food stores. The package labeling should always be consulted since supplements vary greatly in sodium and caloric content and some additional ingredients.

REFERENCES:

[1]Almy, T.P. "Dietary Fiber: Current Role in Therapy and Preventive Medicine." Drug Therapy, 14: 51-59, 1984. [2]Almy, T.P., and Howell, D.A. "Diverticular Disease of the Colon." New England Journal of Medicine, 302:324-332, 1980. [3]Anderson, J.W. "Fiber and Health: An Overview." American Journal of Gastroenterology, 81:892-897, 1986. [4]Burkitt, D. "Fiber as Protective Against Gastrointestinal Diseases." American Journal of Gastroenterology, 79:249-252, 1984. [5]Fleischner, F.G. "Diverticular Disease of the Colon: New Observations and Revised Concepts." Gastroenterology, 60:316-324, 1971. [6]Kirwan, W.O. and Smith, A.N., McConnell, A.A., et al. "Action of Different Bran Preparations on Colonic Function." British Medical Journal, 4:187-189, 1974. [7]Painter, N.S. "The Aetiology of Diverticulosis of the Colon with Special Reference to the Action of Certain Drugs on the Behaviour of the Colon." Royal College of Surgeons of England, 34:98-119, 1964. [8]Taylor I., Duthi, H.I. "Bran Tablets and Diverticular Disease," British Medical Journal, 988-990, 1976. [9]Yang, P. "Dietary Fiber: Its Role in the Pathogenesis and Treatment of Constipation." Practical Gastroenterology, 28-32, 1986.

Ralph M. Myerson, M.D., F.A.C.P., is a clinical professor of medicine at the Medical College of Pennsylvania, and a regular contributor to Better Nutrition.

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