Subscribe to the Magazine for free.
Subscribe for free to keep reading, If you are already subscribed, enter your email address to log back in.
Thanks for subscribing!
Oops! Something went wrong while submitting the form.
Are you a healthcare practitioner?
Thanks for subscribing!
Oops! Something went wrong while submitting the form.

3 Functional Medicine Labs That Can Help Individualize Nutrition Options for Patients With Diverticulitis

Medically reviewed by 
3 Functional Medicine Labs That Can Help Individualize Nutrition Options for Patients With Diverticulitis

A diverticulum is a small pocket formed by the outward bulging of the colon's inner lining. Diverticulosis is the presence of diverticula in the colon. Its prevalence increases with age, affecting 10% of 40-year-olds and at least 60% of people older than 60. (1, 2)

Diverticulitis affects 10-25% of people with diverticulosis at least once. Approximately 130,000 hospitalizations occur annually in the United States due to complications of diverticular disease. Between 1998 and 2005, there was a 26% increase in hospitalizations for acute diverticulitis and a 38% increase in elective operations related to diverticular disease. (1, 2)

Dietary habits play a role in modulating the risk of developing diverticular complications. Keep reading to learn more about diverticulitis and dietary-based approaches that can be implemented to treat and prevent it.


What Is Diverticulitis?

Diverticulitis occurs when diverticula become inflamed or, in some cases, infected. Many people with diverticulosis may never experience symptoms or complications of diverticulosis. Diverticulitis occurs most commonly in men younger than 50 and women aged 50-70. (2)

Diverticulitis is classified as acute or chronic and as complicated or uncomplicated. Acute diverticulitis comes on suddenly and goes away quickly with treatment. However, some people may have recurring flares and develop chronic inflammation within the diverticula. Most diverticulitis cases are uncomplicated, meaning secondary problems do not occur from inflammation or infection. In complicated diverticulitis, severe and chronic inflammation may cause scarring, abscess, fistula, bowel obstruction, or perforation of the affected portion of the colon. Regardless of its classification, diverticulitis requires medical attention and treatment. Mild diverticulitis can be treated with rest, dietary changes, and antibiotics. Severe or recurring diverticulitis may require surgical intervention. (3, 5)

What Causes Diverticulitis?

Diverticula develop when naturally weak places in the colon give way under pressure, causing pouches to protrude through the colon wall. Chronic constipation is a significant contributing factor to the development of diverticulosis. Diverticulitis occurs incidentally, typically when food particles, bacteria, or stool get trapped in the diverticula, causing inflammation or infection. Studies have also suggested that a high active load of cytomegalovirus (CMV) in the colon contributes to intestinal inflammation and diverticulitis. (4, 5)

Risk factors are shared between diverticulosis and diverticulitis. These include genetics, lifestyle factors, and the use of certain medications. Consuming low-fiber, high-fat, and red meat diets is a significant risk factor for developing diverticular disease and complications. Obesity, smoking, and a lack of physical activity also increase the potential for diverticulitis and diverticular bleeding. Exposure to nonsteroidal anti-inflammatory drugs (NSAIDs), steroids, and opioids is associated with diverticulitis. (2, 4)

Symptoms of Diverticulitis

Patients with uncomplicated diverticulitis typically present with left lower abdominal pain. It is important to note that patients of Asian descent present predominantly with right-sided abdominal pain. The pain can be constant or intermittent; it is severe and comes on suddenly, and the intensity may change over time. Patients also commonly present with changes in bowel habits (more commonly constipation than diarrhea), fever, chills, nausea, and vomiting. (3, 4)

A physical examination will reveal tenderness to palpation over the area of the inflamed intestine. Abdominal rigidity, guarding, rebound tenderness, hypoactive bowel sounds, and a palpable intestinal mass may also be noted. (2)

Diverticulitis Diet

A low-fiber diet is recommended during a diverticulitis flare to reduce traffic through the intestines and allow to gut to rest and repair. A two-to-three-day clear liquid diet, including water, tea, broths, and juices without pulp, is often recommended for patients. As a patient feels better, low-fiber and easily digestible foods can be added to the diet. The BRAT and low-residue diets are classic low-fiber diets recommended during periods of digestive rest. Foods emphasized during a low-fiber diet include canned or cooked fruits and vegetables without skin or seeds, lean proteins, milk, yogurt, and white bread, rice, and pastas.

In contrast, a high-fiber, anti-inflammatory diet in combination with a high intake of water is essential in preventing constipation, diverticulosis, and diverticulitis. Studies show that diets rich in fruits, vegetables, and whole grains (i.e., fiber-rich foods) are associated with reductions in diverticulitis risk and hospitalization due to diverticular disease; whereas, a high intake of red meat and processed foods is associated with an increased risk of diverticulitis.

It has been long believed that popcorn and nuts increase the risk of diverticulitis. However, this myth has been debunked by recent research. The Health Professionals Follow-Up Study (HPFS) followed 47,228 men aged 40-75 from 1986 to 2004. It concluded there was no association between nut, corn, or popcorn consumption and the risk of diverticular bleeding and diverticulitis.

Patients should be recommended to at least 25-30 grams of fiber daily. Eating whole grains, beans, legumes, vegetables, whole fruits, nuts, and seeds can help you to meet this goal. The following table lists examples of high-fiber foods and their respective amount of fiber per serving (6).

Functional Medicine Labs That Can Help Individualize Nutrition Options for Patients With Diverticulitis

Acute diverticulitis can be made clinically based on physical examination and patient history; but, because a clinical diagnosis can be inaccurate in up to 68% of cases, laboratory tests and imaging help make an accurate diagnosis. Computerized tomography (CT scan) of the abdomen and pelvis is the imaging modality of choice for acute diverticulitis, but abdominal ultrasound and magnetic resonance imaging (MRI) may be considered. (2)

The following tests can also help functional medicine providers confirm the diagnosis and individualize treatment options for patients with or at risk for diverticulitis.

Inflammatory Markers

Laboratory tests commonly show signs of inflammation per elevations in fecal leukocytes (white blood cells) and serum acute phase reactants, such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).

Comprehensive Stool Test

Comprehensive stool tests can screen for additional inflammatory markers indicative of inflammation specific to the gastrointestinal tract. Fecal calprotectin is elevated in acute diverticulitis and can be used to monitor treatment efficacy (6). A comprehensive evaluation of the gut microbiome screens for sources of bacterial, viral, fungal, and parasitic infection and dysbiosis that can contribute to diverticulitis.

Food Sensitivity Testing

Food allergies and sensitivities can perpetuate intestinal inflammation. Identifying and removing food triggers from the diet can benefit the patient during the treatment of acute diverticulitis and prevent recurrent disease. While elimination-rechallenge diets are one way to do this, blood panels that measure immune responses against food proteins can assist in the timely identification and elimination of problem foods from the diet.



Diverticulosis is common in Western populations, attributed to Western low-fiber dietary patterns. Advanced age and constipation weaken the intestinal walls and predispose to the formation of diverticula. Although less common than diverticulosis, diverticulitis is a diverticular disease complication requiring medical attention to treat acute inflammation and infection within these colonic outpouchings.

Functional medicine testing can assist in assessing the extent of intestinal inflammation when diverticulitis occurs and other gastrointestinal factors, such as the gut microfloral balance and food sensitivities, that can contribute to an increased risk of complicated diverticulitis.

Fortunately, dietary changes can profoundly impact mediating diverticulitis risk and aiding in successful treatment when an acute flare occurs. Diets rich in high-fiber, anti-inflammatory foods are key in supporting healthy bowel movements, a healthy gut microbiome, and reducing intestinal inflammation.

The information provided is not intended to be a substitute for professional medical advice. Always consult with your doctor or other qualified healthcare provider before taking any dietary supplement or making any changes to your diet or exercise routine.
Learn More
No items found.

Lab Tests in This Article

No items found.


1. Weinberg, J. L. (2023, March 17). A Functional Medicine Approach to Diverticular Disease. Rupa Health.

2. Linzay, C.D., & Pandit, S. (2022, August 8). Acute Diverticulitis. National Library of Medicine; StatPearls Publishing.

3. Mayo Clinic. (2020). Diverticulitis. Mayo Clinic.

4. NIDDK. (2019, December 5). Symptoms & Causes of Diverticular Disease. National Institute of Diabetes and Digestive and Kidney Diseases.

5. Cleveland Clinic. (2023, April 10). Diverticulitis. Cleveland Clinic.

6. Dietary Guidelines for Americans. (n.d.). Food Sources of Dietary Fiber | Dietary Guidelines for Americans.

Subscribe to the Magazine for free. to keep reading!
Subscribe for free to keep reading, If you are already subscribed, enter your email address to log back in.
Thanks for subscribing!
Oops! Something went wrong while submitting the form.
Are you a healthcare practitioner?
Thanks for subscribing!
Oops! Something went wrong while submitting the form.