The old warning about nuts, seeds and popcorn in diverticulosis lacks evidence
People with small pouches in the colon wall were long told to avoid nuts, popcorn and seeds. The US digestive diseases institute says no scientific data back that rule, and one study found nuts and popcorn made no difference either way. Most people with the pouches never even know they have them.
Diverticulosis means having several small outpouchings of the colon lining pushing through weak spots in the muscular wall, without inflammation. It is strikingly common in Western countries: roughly half of people over 60 and about 70 per cent of those over 80 have it. It is rare before 40 and uncommon in Asia and Africa. Pouches usually form in the sigmoid colon, where pressure runs high, and in the United States they appear mostly on the left side, while in Asia the right side is more often affected. They are often discovered by chance during a colonoscopy or CT scan.
The best-known explanation is fibre. Building on Thomas Cleave's work, Neil Painter and Adam Smith argued that small, fibre-poor stools force the colon's muscles to squeeze hard, and that years of high pressure push the lining out where blood vessels pierce the wall. The US National Institutes of Health calls this the leading theory but notes it remains unproven. Twin studies suggest about 40 per cent of the tendency is inherited, and other ideas involve nerve cells that coordinate gut movement, the microbiome and inflammation. Connective tissue disorders such as Ehlers-Danlos syndrome also raise the odds.
Complications are less frequent than once thought. A 2013 study found that only about 4 per cent of people with pouches go on to develop diverticulitis, the inflamed form, far below the traditional estimate of 10 to 25 per cent. Diverticular bleeding is nonetheless the commonest cause of sudden bleeding from the lower gut, although around 80 per cent of episodes stop on their own. Complications are more frequent in people taking anti-inflammatory painkillers or aspirin.
There is no blood test for the condition. Contrast CT is the preferred scan during an acute flare, while colonoscopy, which also rules out cancer, is usually scheduled four to six weeks afterwards because it can perforate an inflamed bowel. The Academy of Nutrition and Dietetics recommends 20 to 35 grams of fibre daily to prevent constipation. In the United States the condition costs an estimated 2.5 billion dollars a year in health care.
Source: Diverticulosis
