By John Messmer, MD

Diverticuli are little pockets or pouches that form outside our large intestines. They are almost never seen in rural African and Asian people, but are quite common in the West—about a third of 50-year-old Americans and half of Americans over 80 have diverticular disease. It is most likely caused by insufficient fiber in our diets.

Processed foods in the American diet

Fiber or "roughage" is the part of the food we eat that cannot be broken down and absorbed. It includes structural parts of fruits and vegetables and the husks of grains. For a long time, grains were processed to remove the husk or bran fiber to make white flour and white rice. Partly this was done because people developed a taste for soft white bread and other flour-based products, and partly to remove the high fat "germ" or the seed part of the grain which could turn rancid in storage. As Americans looked for convenience, many people turned to processed foods and away from the fresh vegetables and fruits that could provide adequate fiber.

What causes a diverticulum?

The colon moves food residue from the junction with the small intestine on the right side, up and over to the left, and down to the rectum where it is stored for defecation. If the contents are soft and easy to move, the colon need only squeeze gently to move things through. When the contents are hard, much pressure is generated by the colon in order to keep it moving.

Squeezing under high pressure pushes the inner lining between the muscles of the intestinal wall much like Play-Doh pushes between your fingers if you squeeze it hard. After a while, the inner lining remains pushed out, forming a pocket or diverticulum. High fiber diets trap water and provide substance to the intestinal contents making the material easier to move and less likely to squeeze between the intestine's muscle fibers.

The reason this is bad is that these little pockets get irritated and inflamed and that can lead to infection and bleeding. Infected diverticuli can become an abscess which might rupture, spilling infection into the abdomen—a potentially lethal problem. Diverticuli also can bleed profusely and treatment is often tricky. Someone on an anticoagulant can bleed to death.

For more information on the treatment and prevention of diverticulosis see the following article from TheDietChannel: Dealing with Diverticulosis and Diverticulitis.

What is the recommended amount of fibre in your diet?

Amazingly, all this is due to inadequate fiber in the diet. To get the proper amount of fiber, about 25 to 35 grams per day, try to include vegetables, fruits, legumes, nuts, seeds, and whole grains in your daily diet. Here are some ways to add fiber to your diet:

• Vegetables - broccoli, corn, Brussels sprouts, eggplant, and greens are higher in fiber.
• Fruits - Berries, nuts, seeds, figs, raisins, prunes, cherries, and bananas are also good sources of fiber.
• Beans - kidney, lima, pinto, peas, and lentils have as much as 14-16 grams per cup.
• High fiber cereal - look for at least 4-6 grams of fiber per serving. If you have not developed a taste for these whole grain and bran type cereals, mix a high fiber brand with your favorite cereal.
• Eat:
• • brown rice instead of white rice
  • yams or sweet potatoes
  • baked potatoes (but to a lesser degree)
  • whole grain baked goods
  • whole wheat pasta.

Fiber supplements are also acceptable, particularly for someone trying to avoid overeating. Supplements made from Psyllium seed are available in several forms and artificial fiber supplements are also available.

Benefits and drawbacks to increased fiber intake

There is one drawback to increasing fiber in the short term. Intestinal bacteria break down the fiber into gases that some may find disturbing. However, if fiber consumption is increased gradually, this will be less of a problem. This same bacterial action might have health benefits to slow absorption of sugar and to reduce cholesterol.

An added benefit is that a high fiber diet tends to make us feel full so we eat fewer calories. Since the intestine works more efficiently, constipation is avoided and reduced pressures reduce the risk of hemorrhoids. It has not been proven that fiber reduces the risk of colon cancer, but it is less common in non-Western people whose diets are higher in vegetables and fruits.