Irritable Bowel Syndrome (IBS)

Copyright Gabe Mirkin, M.D.

Republished by permission of the author.

When you complain of belly cramps and alternating constipation and diarrhea, your doctor does a lot of tests. When they are normal, he tells you that you have irritable bowel syndrome or diverticulitis(1). He should also tell you that you eat too much starch and refined carbohydrates.

Most food that you eat is absorbed in your upper intestinal tract, but some non-absorbable starch passes to your colon which is loaded with bacteria that ferment it to release large amounts of gas (2). If the gas can pass outside, it causes no symptoms. However, if anything obstructs the flow of gas, it accumulates behind the obstruction and blows up the tube-shaped colon like a balloon, stretching the colon to its limits and causing pain. Eating food that is low in fiber and high in starch causes hard stool that blocks gas, causing the colon to balloon and form outpouchings called diverticula that hurt. When enough gas accumulates, it blows out the hard stool which is followed by diarrhea. Then the process repeats itself to cause alternating constipation and diarrhea.

Most people who suffer from irritable bowel syndrome do not have a serious disease. Fewer than one in 20 suffers from ulcers, cancers or pancreatitis up to 30 years later (3). The treatment for irritable bowel syndrome is to eat lots of fruits, vegetables, whole grains and beans and avoid high-starch, low-fiber foods such as most bakery products and pastas. Whole grains, seeds, beans and vegetables keeps everything soft by filling with water and letting gas pass on its way. If that doesn't work, 5HT inhibitors such as Alosetron, Granisetron and Ondansetron may help (4).

The notion that people with diverticulitis need to avoid corn and other seeds (because they "may get stuck in the pockets") is outdated and has never been proven to be an actual concern. If your doctor has given you this instruction, ask him or her to show you data. A healthful diet for a person with diverticulosis includes lots of high-fiber foods.

1) SF Phillips. Irritable bowel syndrome: making sense of it all. Best Practice & Research in Clinical Gastroenterology, 1999, Vol 13, Iss 3, pp 489-503.
2) Lancet, October 10, 1998.
3) DM Owens er al. Arthritis and Rheumatism, 1995(Jan); 122:107.
4) MJG Farthing. Irritable bowel syndrome: new pharmaceutical approaches to treatment. Best Practice & Research in Clinical Gastroenterology, 1999, Vol 13, Iss 3, pp 461-471.

Checked 8/9/05

Dr Mirkin's reports and opinions are for information only, and are not intended to diagnose or prescribe. For your specific diagnosis and treatment, consult your doctor or health care provider.

Dr Mirkin is a graduate of Harvard University and Baylor University College of Medicine. He is one of a very few doctors board-certified in four specialties: Sports Medicine, Allergy and Immunology, Pediatrics and Pediatric Immunology. For more information visit URL: Dr Mirkin

My comment

During the first month, when building the habit of eating more fiber-rich foods, supplementation with psyllium husk will soften the contents of the bowel and encourage easier passage. One tablespoon in a glass of water is sufficient to begin the transition. This can be gradually increased to three times per day over the first few weeks. Psyllium husk is safe to use as a long-term supplement to fiber in foods.