High-Fiber Diet

High-fiber diets are primarily effective for preventing diverticulitis and managing diverticulosis (the presence of diverticula without inflammation). The mechanism works through several pathways:

A high intake of dietary fiber is associated with increased stool bulk and reduced transit time and may require less pressure during defecation, and may therefore reduce the possibility for the mucosa to herniate through the weak areas in the colon. Dietary fibre intake and the risk of diverticular disease: a systematic review and meta-analysis of prospective studies - PMC Additionally, bacterial fermentation of dietary fiber produces short-chain fatty acids Dietary fibre intake and the risk of diverticular disease: a systematic review and meta-analysis of prospective studies - PMC which can have beneficial effects on colon health.

Fiber softens the stool and helps prevent constipation. It also can help decrease pressure in the colon and help prevent flare-ups of diverticulitis. Diverticular Disease and Diet | Patient Education | UCSF Health The fiber helps create softer, bulkier stools that move more easily through the colon, reducing the high pressure that can cause diverticula to form or become inflamed.

However, it's important to note that high-fiber diets are not recommended during acute diverticulitis flare-ups. During active inflammation, a low-fiber diet is typically prescribed to allow the digestive tract to rest and heal.

The implementation of a high-fiber diet for diverticular disease follows specific guidelines:

Fiber Goals: The Dietary Guidelines for Americans, 2020–2025, recommends a dietary fiber intake of 14 grams per 1,000 calories consumed. For example, for a 2,000-calorie diet, the fiber recommendation is 28 grams per day. Eating, Diet, & Nutrition for Diverticular Disease - NIDDK Eat 30-35 grams of fiber daily. Spread out the fiber throughout your meals.

Gradual Introduction: Cater says if your current diet is lower in fiber and heavier in refined flour, meat and cheese, it may take a while for your digestive system to get used to a change. Start out with a few substitutions, and gradually work your way up to including more and more high-fiber choices into your meal planning. Foods for Diverticulosis and Diverticulitis | Johns Hopkins Medicine

High-Fiber Food Sources: Cater says people with diverticulosis can benefit from eating fiber-rich foods, including: Whole grains, such as quinoa, bulgur, teff, barley, popcorn, oats, shredded wheat or bran cereals, and whole grain breads · Beans and legumes, including black beans, kidney beans, chickpeas and lentils · Vegetables such as greens (collard, kale, spinach), broccoli, cauliflower and carrots · Fruit, especially blackberries and raspberries, but also avocado, blueberries, strawberries, apples and pears (with the skin on), kiwi and oranges Foods for Diverticulosis and Diverticulitis | Johns Hopkins Medicine

Hydration Requirements: "Drinking enough water is essential for keeping your bowels healthy and functioning." How much water is enough? "The number of ounces I recommend is about half the person's body weight in pounds," she says. So, for example, a person who weighs 180 pounds would aim for about 90 ounces of water each day. Foods for Diverticulosis and Diverticulitis | Johns Hopkins Medicine

During Flare-ups: If you need hospital care for a serious bout of diverticulitis, you may be given fluids through a vein first. You also may need medicines such as antibiotics. Then you'll likely start with clear foods and liquids because these are easy to digest. Diverticulitis diet After recovery, your healthcare professional likely will have you slowly add low-fiber foods. This way of eating can help the digestive tract heal from a flare. Diverticulitis diet

The scientific evidence for high-fiber diets in diverticular disease prevention is substantial, though evidence for treatment of active diverticulitis is more limited:

Prevention Evidence: A major meta-analysis found that five prospective cohort studies with 19,282 cases and 865,829 participants were included in the analysis of dietary fibre and diverticular disease risk. The summary RR was 0.74 (95% CI 0.71–0.78, I2 = 0%) per 10 g/day. There was no evidence of a nonlinear association between dietary fibre intake and diverticular disease risk, pnonlinearity = 0.35, and there was a 23%, 41% and 58% reduction in risk for an intake of 20, 30, and 40 g/day, respectively, compared to 7.5 g/day. Dietary fibre intake and the risk of diverticular disease: a systematic review and meta-analysis of prospective studies - PMC

Treatment Evidence: However, for treating symptomatic uncomplicated diverticular disease (SUDD), nineteen studies were included, nine with dietary fiber and 10 with supplemental fiber, with a high heterogeneity concerning the quantity and quality of fibers employed... Up to now, high-quality evidence on the efficacy of fiber treatment for the reduction of symptoms in SUDD and for the prevention of acute diverticulitis, is lacking. MDPIPubMed Central

Contradictory Evidence: Notably, one significant study found contradictory results: Instead, the quartile with the highest fiber intake had a greater prevalence of diverticulosis than the lowest (prevalence ratio = 1.30; 95% confidence interval, 1.13–1.50). A High-Fiber Diet Does Not Protect Against Asymptomatic Diverticulosis - PMC This suggests the relationship between fiber and diverticulosis development may be more complex than previously thought.

Systematic Review Conclusions: Despite the lack of evidence, high-fibre diet as treatment for symptomatic diverticular disease, is been recommended in several guidelines. All of the evidence is based on two small sample size randomised clinical trials, with inconsistent results, or observational uncontrolled studies more than 20 years ago. A systematic review of high-fibre dietary therapy in diverticular disease - PMC