Diverticulitis: What It Is, Why It Happens, and How to Prevent It
Diverticulitis is one of those diagnoses that tends to surprise patients — in part because many people don't know they have diverticulosis (the underlying condition) until they end up in the emergency department with severe abdominal pain.
Understanding diverticular disease — what it is, who gets it, and most importantly, how to reduce your risk — is worthwhile for anyone over 40.
Diverticulosis: The Foundation of the Problem
Diverticulosis refers to the presence of small pouches — diverticula — that develop in the wall of the colon. They form at weak spots in the colon wall, typically where blood vessels penetrate the muscle layer. Diverticulosis is extremely common in Western countries: it affects roughly 35% of adults under 50, 50% of adults over 60, and nearly 70% of adults over 80.
Most people with diverticulosis have no symptoms and don't know they have it. It is often discovered incidentally during a colonoscopy performed for other reasons. By itself, diverticulosis doesn't require treatment.
When Diverticulosis Becomes Diverticulitis
Diverticulitis occurs when one or more diverticula become inflamed or infected — typically when fecal matter or bacteria become trapped in the pouches. The result is often sudden, significant left lower abdominal pain (though right-sided pain is also possible), fever, nausea, and changes in bowel habits.
Most cases of uncomplicated diverticulitis are managed with antibiotics and dietary modification (clear liquids initially, then low-fiber until the inflammation resolves, then a gradual return to a high-fiber diet). Complicated diverticulitis — involving abscess, perforation, fistula, or obstruction — may require hospitalization, IV antibiotics, drainage procedures, or surgery.
What Causes Diverticulitis?
The exact mechanism is still debated, but diverticulitis is associated with low dietary fiber intake, physical inactivity, obesity, red meat consumption, and certain medications (NSAIDs, steroids, opioids). A low-fiber diet leads to harder stools, increased pressure in the colon during bowel movements, and the development of diverticula over time.
Prevention Strategies
While you can't reverse existing diverticulosis, you can significantly reduce your risk of diverticulitis:
Eat a high-fiber diet: Aim for 25–35 grams of fiber per day from vegetables, fruits, legumes, and whole grains
Stay well hydrated: Adequate water intake keeps stool soft and reduces colonic pressure
Exercise regularly: Physical activity reduces constipation and has been associated with lower diverticulitis risk
Maintain a healthy weight: Obesity is an independent risk factor for diverticular complications
Limit red and processed meat: Associated with higher diverticulitis incidence
Avoid NSAIDs and steroids when possible: These medications are associated with diverticular complications
Old Advice That's No Longer Recommended
For years, patients with diverticulosis were told to avoid nuts, seeds, popcorn, and corn — the theory being that these particles could lodge in diverticula and trigger inflammation. Multiple large studies have found no evidence that this is true. These restrictions are no longer recommended and may actually be counterproductive by discouraging a high-fiber diet.
What About Colonoscopy After Diverticulitis?
After a confirmed episode of diverticulitis, colonoscopy is generally recommended 6–8 weeks after resolution to rule out colorectal cancer (which can sometimes mimic diverticulitis on imaging) and to assess the colon. Our gastroenterologists will guide you through the appropriate timing and follow-up.
📅 Questions about diverticular disease or due for a colonoscopy? Call (908) 851-2770 or book online.
Medical Disclaimer: This blog post is intended for general informational and educational purposes only and does not constitute medical advice.
