You know everything you’ve heard about how constipation and a low-fiber, high-fat and meat-rich diet raises a person’s risk of developing diverticulosis? It may be all wrong, according a new study.
In diverticulosis, out-pouchings form in the wall of the colon. Colonic contents — you know what we’re talking about — can get stuck in these knuckle-size cul-de-sacs. If the tissue becomes inflamed, the condition is called diverticulitis. In the worst cases, an abscess can form or the wall can rupture, causing death.
About one-third of American adults are believed to have diverticulosis. A fraction of them — estimates range from 10 to 40 percent — go on to develop symptoms, often just pain, sometimes the more serious complications.
In a study in the journal Gastroenterology, Anne F. Peery, a physician at the University of North Carolina School of Medicine, looked at the relationship between what 2,100 people said they ate and what their colons looked like on routine colonoscopy.
People were asked how frequently they consumed 124 food items in the year before the procedure. Those reporting the highest fiber intake were 30 percent more likely to have diverticulosis than those reporting low fiber. People reporting more than 15 bowel movements a week were nearly twice as likely to have the problem as those having less than one bowel movement a day. The researchers found no relationship between diverticulosis and meat or fat intake or physical activity.
This is just the opposite of what physicians are taught.
The prevailing theory is that a dearth of fiber leads to constipation, which forces the colon to contract with greater force. Over time, that leads to the outpouchings.
“We may have to rethink the mechanism for why we develop diverticular disease,” Peery said. She and her colleagues are looking for other groups to study.
The relationship between diet and “diverticular disease” — the term encompasses the condition in all its manifestations — was proposed by English surgeon Denis P. Burkitt in 1971 in a famous paper in the Lancet medical journal. He wrote that in 20 years as a medical missionary in Africa, he’d never seen a case of diverticulitis.
Many subsequent studies, however, had methodological problems that made the findings questionable. Some good studies, however, found a protective effect from high-fiber intake.
For example, researchers at the University of Oxford followed 47,000 people — one-third of them vegetarians — in England and Scotland. The probability of being admitted to the hospital for diverticulitis, or dying from the disease, was slightly lower in the vegetarians (3 percent) than in the meat eaters (4.4 percent). People reporting the highest-fiber diets had the lowest risk.