A 60-year-old man comes to clinic following an episode of diverticulitis. He was treated with a course of amoxicillin clavulanate and improved. He asks, “What is the best way to prevent a recurrence?” Which answer would you give him?
A. Chronic antibiotics.
B. Avoid nuts and popcorn.
C. Regular laxative use.
D. High residue diet.
The classic teaching has been to advise patients who have had diverticulitis to avoid high-residue foods such as nuts, seeds, and popcorn. An additional classic teaching has been to advise patients with active diverticulitis to avoid solid foods and a higher-fiber diet during their acute illness.
Are these classic teachings right? Is there evidence to support these approaches?
The prevailing thought behind avoidance of high-residue foods causing diverticulitis flares was that indigestible nuts, seeds, corn, and popcorn could enter, block, or irritate a diverticulum, result in diverticulitis, and possibly increase the risk of perforation.1,2
In an article based on a survey of gastroenterologists, published in 1999, 68% recommended a low-residue diet for patients with diverticulitis, and half felt avoidance of seeds and nuts was of no value.3
Dr. Lisa L. Strate and colleagues studied a cohort of 47,288 men between the ages of 40 years and 75 years who were initially without any form of diverticular disease.4 These men were followed through food-frequency questionnaires over the course of 18 years. The main outcome was development of diverticulitis or diverticular bleeding. A total of 801 cases of diverticulitis occurred, as did 383 cases of diverticular bleeding.
There was an inverse correlation between nut and popcorn consumption and the development of diverticulitis. Comparing individuals with the highest nut and popcorn consumption with those with the lowest consumption yielded a hazard ratio of 0.8 for nuts (95% confidence interval, 0.63-1.01) and a hazard ratio of 0.72 for popcorn (95% CI, 0.56-0.92). These results were the opposite of the classic belief that eating nuts and popcorn increased the risk of diverticulitis.
There is no mention of avoidance of nuts or popcorn for the prevention of diverticulitis in the most recent practice parameters released by the American Society of Colon and Rectal Surgeons.5
High-residue diets including fiber may be beneficial in reducing further episodes of diverticulitis, although this remains somewhat controversial.
Several retrospective studies in patients with symptomatic diverticulosis and diverticulitis showed decreases in symptoms and decreased progression to more complicated disease.6,7,8,9 In a recent study of diet for patients hospitalized with acute diverticulitis, 256 patients were evaluated.10 A total of 65 patients received nothing by mouth (NPO), 89 received a clear liquid diet, 75 received a full liquid diet, and 27 received solid foods. Patients who received a full liquid diet (HR, 1.66; 95% CI, 1.19-2.33) or solid foods (HR, 2.39; 95% CI, 1.52-3.78) were more likely to be discharged than were patients who received a clear liquid diet (HR, 1.26; 95% CI, 1.52-3.78) or who were NPO (the reference group).
A diet high in fiber is recommended by the National Digestive Disease Information Clearinghouse patient portal and the American Society of Colon and Rectal Surgeons for patients with diverticular disease.5,11 But the Practice Parameters Committee of the American College of Gastroenterology did not believe that there is sufficient evidence of a significant role for fiber in preventing recurrent diverticulitis to make a recommendation.1,12
So, where does this leave us?
I think we can stop recommending that our patients with diverticular disease avoid seeds, popcorn, and nuts. Fiber is very likely helpful in decreasing the risk of development of diverticulosis and may be helpful in patients with established diverticular disease, without evidence of harm. For patients who are having an acute flare of diverticulitis, resuming a regular diet as soon as feasible is likely the best option.
Dr. Paauw is professor of medicine in the division of general internal medicine at the University of Washington, Seattle, and he serves as third-year medical student clerkship director at the University of Washington. Contact Dr. Paauw at dpaauw@uw.edu.
References
1. Nutr Clin Pract. 2011 Apr;26(2):137-42.
2. Am J Dig Dis. 1958 May;3(5):343-50.
3. Dis Colon Rectum. 1999 Apr;42(4):470-5.
4. JAMA. 2008 Aug 27;300(8):907-14.
5. Dis Colon Rectum. 2014 Mar;57(3):284-94.
6. Br Med J. 1972 Apr 15;2(5806):137-40.
7. Br J Surg. 1980 Feb;67(2):77-9.
8. Ann R Coll Surg Engl. 1985 May;67(3):173-4.
10. Int J Colorectal Dis. 2013 Sep;28(9):1287-93.
11. What I need to know about diverticular disease. National Digestive Diseases Information Clearinghouse.