Crappy recommendations

Doctors should stop telling their patients with diverticular disease to avoid nuts, seeds, corn, and popcorn. Even though this has been our practice for nearly a century, there has never been any sound evidence that such dietary precautions would result in fewer complications from diverticula. In fact, we now have some fairly sound evidence that those recommendations are completely off course: a large study involving 47,228 men over an 18-year period demonstrated that higher rates of popcorn and nut consumption led to lower rates of diverticulitis. Yet large numbers of physicians and other health care providers still provide outdated recommendations for their patients.

The concept that nuts, seeds, and kernels could cause problems with diverticulosis came about in the early 1900s. Prior to that time, diverticular disease of the colon was a rare condition.  The Industrial Revolution greatly reduced the fiber content of the Western diet as a result of milling and refining grains on an increasing scale. After 20 or 30 years of this, diverticulosis rates started climbing dramatically. Surgeons saw more and more cases of diverticular perforation, one of the more critical complications of diverticular disease. They encountered these patients with an obvious intraabdominal catastrophe, and had to operate on them to try to save their lives.  At surgery, they identified a hole in the colon with a little outpouching, the diverticulum, often with a kernel or seed stuck in it.  This observation led surgeons to conclude that the wedged item was somehow responsible for the calamity.

So the word went out that patients with diverticular disease should avoid these food items like the plague. A low-residue diet became the standard recommendation for diverticulosis patients. This concept persisted through the 1960s and 1970s when investigators were determining that diverticula developed from increased intraluminal pressure which, in turn, was a major consequence of low fiber diet. The recommendations for a low-residue diet were 180 degrees in the wrong direction.

Even though there is now solid evidence that the previous recommendations were absolutely misguided, it would take a paradigm shift for everyone in medicine to start handing out the correct recommendations.