So far, there is a belief that eating nuts, seeds, and corn increases the risk of diverticulitis. Often clinicians forbid patients with diverticular disease to eat these foods. However, this belief is not supported by medical evidence.

Does Eating Beans, Nuts, Seeds and Corn Increase the Risk of Diverticulitis?
Eating Peanut
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What is Diverticular Disease?

Diverticular is a protrusion on the intestinal wall that forms a colon sac, which is only covered by a thin surface layer on that part of the colon. The protrusion of the diverticular sac covered by a thin wall is commonly referred to as a false diverticular or pseudodiverticular. In contrast, the diverticular found in the colon is called a true diverticular, which is usually congenital.

The diverticular disease is divided into several divisions based on certain criteria such as:
  1. Diverticulosis is a condition where one or more diverticles are found in the colon.
  2. Diverticula is a condition where many diverticles are found.
  3. Pre diverticular is a condition where the diverticula pouch protrudes but has not passed the colon wall.
  4. Peridiverticulitis is a sign of inflammation found through the diverticula.
  5. Diverticulitis is a condition when the colonic diverticles break down. It causes inflammation and infection of the colon and surrounding tissues and can be characterized by free fluid in the peritoneal cavity.

The diverticulum can have various complications, such as diverticulitis and diverticular bleeding. Approximately 10–35% of patients with diverticular disease report complications, so patients often seek dietary and lifestyle recommendations to reduce the risk of these complications.

The Theory Behind the Ban on Nuts and Seeds

Previously, clinicians often recommended diverticular disease patients not to eat nuts, seeds, corn. The basis for this advice is the assumption that these foods easily enter the diverticulum sac. They cause mucosal abrasion or obstruction and can cause inflammation or bleeding (intraluminal trauma).

However, the actual biological mechanisms behind diverticulitis and other complications of diverticular disease are not well known. Apart from intraluminal trauma, increased colonic pressure, impaired colon wall integrity, and colonic flora changes may play a role. To date, there is no medical evidence to suggest that nuts, seeds, corn are risk factors.

Medical Evidence Breaking the Prohibition of Consuming Nuts and Seeds

Strate et al. conducted a large prospective cohort study. Over 18 years to study the association of nuts, corn consumption with diverticulitis risk. This study involved 47228 men (with a medical background) aged 40–75 years to complete medical and diet questionnaires independently.

At study entry, all participants did not have diverticulosis or inflammatory bowel disease. However, during the 18 years of the study, 801 cases of diverticulitis and 383 cases of diverticular bleeding were found. The researchers found that participants who ate nuts and popcorn more frequently (at least 2 servings/week) did not have an increased risk of diverticulitis compared to participants who consumed <1 serving/month.

Consumption of nuts and popcorn in that study was associated with reduced diverticulitis risk. However, consumption of corn was reported neither to increase nor decrease the diverticulitis risk. These three foods (beans, corn, popcorn) were also not associated with diverticular bleeding.

That study had also shown that peanut consumption reduces diverticulitis recurrence (38 lower recurrences in every 1000 people every five years). Popcorn consumption also results in 53 lower recurrences in every 1000 people every five years. However, the results regarding the protective effects of nuts and popcorn are still low quality and need further investigation. The fact that has been proven at this time is the consumption of nuts, corn, and popcorn does not increase the risk of diverticulitis.

The Recommended Diets for Patients with Diverticular Disease 

What is the recommended diet for diverticulitis?
Many guidelines currently recommend the consumption of a high-fiber diet for patients with diverticular disease. The American Gastroenterological Association Institute guidelines propose a fiber-rich diet for patients with a history of acute diverticulitis and do not prohibit the consumption of whole grains, nuts, corn.

Some studies still show dubious results about the benefits of fiber-rich foods in preventing diverticulitis, in which the consumption of fibrous foods is not reported to be associated with a reduced risk of diverticulitis. However, several other studies show that fiber foods play a positive role in diverticulitis. Since the consumption of fibrous foods is generally beneficial for gastrointestinal health, its consumption is still recommended.

What Are Diverticulosis Diet Foods to Avoid?
Diets that need to be avoided by diverticular disease patients are diets high in refined carbohydrates, high-fat dairy products, and red meat. A prospective cohort study of 46,295 men showed that this diet increases the risk of diverticulitis. In contrast, a diet rich in vegetables, fruit, and whole grains may reduce diverticulitis risk.