In the past, people with small pockets (diverticula) in the lining of the colon were told to avoid nuts, seeds, and popcorn. It was thought that these foods could lodge in diverticula and cause inflammation (diverticulitis). However, there is no evidence that these foods cause diverticulitis. Patients with diverticular disease are often advised to avoid nuts, corn, popcorn, and seeds to reduce the risk of complications.
However, there is little evidence to support this recommendation. As Cleveland Clinic points out, seeds are actually part of a high-fiber diet, which, once again, is recommended to reduce the risk of diverticulitis. A healthy, high-fiber diet is actually the best medicine against diverticulitis, and seeds and nuts certainly meet the requirements. Similarly, he added, there is no evidence that taking seeds, including the tiny seeds found in strawberries and blueberries, increases the risk of diverticulitis.
However, the consumption of strawberries and blueberries (fruits with small seeds) was not associated with diverticular complications. Since at least the 1950s, many doctors have advised patients with diverticular disease to restrict nuts, corn, popcorn, and even seeded vegetables such as tomatoes, on the theory that the non-digestible components of these foods would lodge in bags and cause symptoms. However, since there are no significant gender differences in the disorder, walnuts, corn, popcorn, and small seeds are likely to be safe for all individuals with diverticular disease and for those who want to avoid the occurrence of the condition. Surprisingly, the study revealed that those who ate more seeds and nuts actually had a lower risk of developing diverticular disease.
Surprisingly, despite the lack of evidence to support this dietary restriction, a study published about ten years ago revealed that 47% of colorectal surgeons advised patients with diverticular disease to avoid nuts and seeds. We used to think that a seed or a nut clogged the colon sac, and that's what caused it to swell or break. In addition, although they were unable to specifically measure seed intake, they did not observe a significant association between intake of blueberries and strawberries (which contain small seeds) and diverticular complications, so there should be no need to avoid the small-seed diet. So, if small hard granules of stool (mostly composed of non-digestible waste and bacterial mass) don't cause an infection, why would a small seed or nut cause a problem? However, people still try very hard to avoid seeds, nuts, and corn, which causes them a great deal of pain when it comes to meal options.