Diverticulitis is a condition characterized by severe abdominal pain and inflammation—sometimes with infection—due to blocked pouches in the colon. It leads to over 200,000 annual hospitalizations and almost twice that many emergency department visits in the United States. Surprisingly, over 50 percent of Americans aged 60 and above, and over 60 percent of those aged 80 and above, have pouches called diverticula in their colons, a condition known as diverticulosis. Less than 5 percent of those with diverticulosis develop diverticulitis.

Diverticulitis increased by 50 percent in the United States from 2000 to 2007, particularly in younger people, with this surge linked to factors like obesity, diet, and physical inactivity.

This prevalence underscores the significance of recent evidence challenging the conventional approaches to diverticulitis and questioning the standard use of antibiotics, surgery, and dietary guidance.

Diverticulitis arises when diverticula become inflamed or infected. Common signs of diverticulitis include:

• Abnormally high number of white blood cells
• Elevated C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR)
• Computed tomography (CT) scan showing inflammation and thickening of the fatty tissue around the colon or bowel wall and inflamed or infected pouches in the colon, characteristic findings of diverticulitis that do not typically indicate another condition
• Blood in the stool
• Fever
• Rapid heart rate
• Low blood pressure
• Abdominal or rectal tenderness

Symptoms, which can vary widely, include:

• Abdominal pain, typically in the lower left, but more often the upper right for those of Asian descent
• Abdominal distension
• Loss of appetite
• Nausea or vomiting
• Constipation or diarrhea
• Painful or difficult urination
• Cramping

Acute diverticulitis is serious and can be life-threatening, so prompt medical attention is crucial.

For years, experts linked diverticular disease to a low-fiber diet, which can lead to hard stools and increased colon pressure, potentially damaging the colon’s wall. Understanding this sets the stage for exploring two key theories proposed to explain the onset of diverticulitis across different age groups.

The “traumatic theory” suggests that in older people, high pressure in the colon can create weak spots that get damaged by hard stool impaction in the diverticula, leading to inflammation and bacterial overgrowth. This idea aligns with the thought that not eating enough fiber can lead to hard stool that needs more pressure to move. However, evidence supporting this theory is lacking. In fact, no conclusive link has been established between diverticulitis and stool form, straining, or feelings of incomplete bowel movements. The role of fiber in the diet in preventing diverticulitis is still unknown.

Additionally, the role of the gut microbiome in diverticular disease remains unclear. Some studies have found differences in specific microbes in the gut of people with diverticular disease, but these findings are limited and inconsistent. Consequently, a cause-and-effect relationship between the microbiome and diverticulitis remains elusive.

As standard treatment shifts away from the routine use of antibiotics, it could affect how often diverticulitis recurs, considering the impact antibiotics can have on the balance of gut bacteria. Further research is needed to understand the connection between the microbiome and diverticulitis fully.

What Happens in Your Body?

Once we know what might cause diverticulitis, it is important to see how it affects the body. Diverticula form in weak parts of the colon, maybe according to one of the abovementioned theories. When these diverticula get inflamed, a chain reaction starts in the body. The inflammation leads to swelling and irritation in the affected area, causing pain, tenderness, and discomfort.

If the inflammation continues, it can lead to complications like abscesses or perforations in the diverticula, which can cause stool leakage into the abdominal cavity. This causes peritonitis, a serious infection with swelling of the abdominal lining. Swelling can also narrow the path stool takes through the intestines, leading to obstruction and increased pressure, restricting bowel movements. Damage to the intestinal wall can create fistulas or abnormal connections to other organs or tissues, such as the skin or bladder.

Diverticulitis is part of a broader spectrum of diverticular disease that ranges from diverticulosis to diverticulitis, with various conditions in between. Each type has its own set of symptoms and requires different treatment approaches. Knowing these types makes it easier to understand why practitioners might want to exclude certain conditions when evaluating symptoms.

Most people with diverticulosis will not show symptoms. However, about 25 percent experience an episode of symptomatic diverticulosis, and less than 5 percent have an episode of acute diverticulitis. Symptomatic diverticulosis can be classified into three types:

1. Symptomatic uncomplicated diverticular disease (SUDD): This involves chronic symptoms like abdominal pain without acute inflammation. Some consider SUDD to be a chronic type of diverticulosis.
2. Segmental colitis associated with diverticulosis (SCAD): This form of colitis affects areas of the colon with diverticula. However, unlike diverticulitis, SCAD primarily affects the colon between the diverticula and not the diverticula themselves. Patients with SCAD often have chronic diarrhea, abdominal pain, and sometimes blood in the stool.
3. Diverticulitis: This is when the diverticula become inflamed or infected, leading to symptoms like those described below. Diverticulitis can be acute, with sudden and severe symptoms; recurrent, with repeated episodes of acute diverticulitis; or chronic, where symptoms persist over time due to ongoing inflammation or repeated episodes.

Acute diverticulitis can be further divided into the following categories:

• Uncomplicated diverticulitis, which involves a sudden onset of symptoms and inflammation without severe complications such as abscesses or perforations. Symptoms can often be managed conservatively with dietary modifications and, if necessary, antibiotics.
• Complicated diverticulitis, which involves more severe symptoms and complications, like those discussed below. Complicated diverticulitis often requires more intensive management, possibly including hospitalization or surgery.

The chances of developing diverticulitis depend on factors like sex, age, race, and lifestyle.

The following factors have been identified as contributors to risk:

• Diet: Though the evidence is not strong, a high-fiber diet may help prevent diverticulitis. Vegetarians have an approximately 30 percent less risk of diverticulitis.
• Sex: It is more common in men than women until around age 60, when it becomes about equally common between the sexes. Males and younger individuals are more prone to having repeat episodes, but women are more prone to hospitalization.
• Race: People of European descent are more likely to be hospitalized for diverticulitis.
• Body mass index (BMI): Obesity, waist circumference, and waist-to-hip ratio are positively associated with the risk of diverticulitis. In fact, obesity, defined as a BMI above 30, has been shown to increase the risk of diverticulitis by up to 80 percent.
• Lack of exercise: Being physically inactive can increase the risk of diverticulitis. Regular vigorous exercise lowered the chances of diverticulitis and bleeding from diverticula in men by 25 percent and 46 percent, respectively.
• Smoking: Smoking is a risk factor for diverticulitis, likely due to its detrimental effects on colonic health and function. A Swedish mammography cohort study found the risk of hospitalization from diverticular disease was 24 percent higher for smokers than for nonsmokers.
• Alcohol: Some studies have found that heavy drinking increases the risk of diverticulitis, particularly diverticular bleeding.
• Medications: Certain medications, like NSAIDs, acetaminophen, aspirin, opiates, corticosteroids, and other drugs that suppress the immune system, may raise the risk of diverticulitis and perforations.
• Structure of the colon: Changes in the structure of the colon, especially the health and strength of its wall, can increase the chances of developing diverticulitis.
• Motility: Colonic motility is how the colon moves and works. Disordered motility has been linked to a higher risk. Furthermore, disturbances in how the nerves and muscles communicate in the gut in diverticulitis affect motility.
• Vitamin D levels: Low vitamin D levels and ultraviolet light exposure have been associated with an increased risk.
• Genetics: Studies with twins show that genetics have a part in causing diverticulitis, accounting for about 40 percent to 53 percent of the risk. While this suggests a genetic predisposition, it does not ensure the development of the disease. Diet and lifestyle can affect how genes work, so this factor may be somewhat modifiable.
• Age: The risk of diverticulitis increases with age, rising markedly after age 40, and it increases more in women after age 60.

Moreover, individuals with weakened immune systems may be at a higher risk of developing acute diverticulitis. The frail and malnourished also face increased risks of complications and death.

If your practitioner suspects you have diverticulitis, he or she will check your abdomen for tenderness, listen to its sounds with a stethoscope, and conduct other tests like checking your heart rate, blood pressure, and temperature. He or she might also perform a rectal or pelvic exam.

To further direct diagnosis, your practitioner may order various tests to identify signs of infection or inflammation and rule out other conditions. These tests include:

• Complete blood count (CBC): This checks for an increased white blood cell count, signaling infection or inflammation.
• Other tests: These may include liver enzymes to assess liver function, erythrocyte sedimentation rate (ESR) to measure inflammation, and C-reactive protein (CRP) as another marker of inflammation. A stool test or urinalysis may help diagnose or rule out other conditions.
• Pregnancy test: For women of childbearing age, a pregnancy test may be ordered to rule out pregnancy as a cause of symptoms and to guide safe imaging decisions.
• Imaging tests: A CT scan is commonly used to diagnose diverticulitis and assess its severity. Ultrasound and MRI are alternatives, especially useful during pregnancy or when avoiding contrast dye.

After completing the necessary tests, a colonoscopy may be ordered if further evaluation is needed. During a colonoscopy, diverticulosis is often found. Current guidelines advise scheduling a colonoscopy within six to eight weeks after a flare-up, especially if you have not had one recently. Your gastroenterologist may recommend it regardless to confirm the diagnosis and ensure there are no other issues, like colon cancer, especially if you did not get a CT scan.

Inflamed diverticula can lead to serious complications in about 25 percent of first episodes, but this risk decreases with subsequent episodes. Complications often require prompt medical attention and include:

• Bleeding: When a blood vessel ruptures, causing bleeding. Up to 5 percent of patients may have bleeding, which usually stops on its own. About 20 percent of these cases need medical or surgical intervention to be controlled.
• Perforation: A small hole or tear forms in the colon, causing bowel contents, including bacteria, either to leak into an area contained by other tissues or leak freely into the abdominal cavity.
• Abscess: Pus collects in an inflamed area. Up to 30 percent of diverticulitis flares can involve abscesses. If antibiotics fail to work, surgery or drainage may be needed.
• Peritonitis: This is inflammation of the membrane lining the abdomen caused by a colon perforation.
• Bowel obstruction: This is narrowing or blockage in the colon due to an abscess, swelling, or scar tissue. A partial obstruction may resolve on its own, but a complete blockage will require surgery.
• Fistula: An abnormal connection between organs or tissues, like between the colon and bladder, can cause symptoms such as urinary tract infections or passing gas or stool through the urine. Surgery to remove the fistula and affected part of the colon is usually required.
• Pylephlebitis: In this rare complication of abdominal infections, infected blood clots develop in the abdomen.

Getting diverticulitis again is not seen as a complication, but up to 35 percent of people who did not have surgery the first time might get it again. Ongoing pain and discomfort, the possible need to take antibiotics again, and the inconvenience it brings are valid concerns. Fortunately, getting diverticulitis again does not raise the risk of complications.

Treatment approaches for diverticulitis have evolved over time. In the past, antibiotics, pain control, and diet changes were standard treatments for acute diverticulitis, and elective surgery was common after the second acute episode. However, recent evidence suggests a more conservative approach for acute uncomplicated cases. Treatment may include the following.

1. Antibiotics

For acute uncomplicated cases of diverticulitis, studies show that antibiotics do not speed up recovery, reduce the need for surgery, or prevent complications. Therefore, practitioners might only prescribe antibiotics to patients with weakened immune systems, those with a sepsis infection, or for other reasons based on individual situations.

When antibiotics are necessary, the American Gastroenterology Association recommends either a combination of oral fluoroquinolone (Cipro, Levaquin) and metronidazole (Flagyl) or oral amoxicillin-clavulanate (Augmentin). However, it is important to note that fluoroquinolones carry boxed warnings due to serious side effects, including tendon rupture, nerve damage, and mental health disturbances. Therefore, its use should be considered cautiously.

Rifaximin, an alternative antibiotic for uncomplicated diverticulitis, primarily acts within the gut due to minimal absorption into the bloodstream. It targets bacterial overgrowth, improves stool quality, and promotes beneficial gut bacteria with anti-inflammatory effects, all while minimizing harmful bacteria.

Most people with uncomplicated diverticulitis can get better at home. However, if you have a severe case, you might need to be admitted to the hospital for IV antibiotics and close monitoring.

2. Pain and Symptom Management

Evidence has not established the effectiveness of mesalamine for preventing recurrence, but it may be prescribed to reduce inflammation. Acetaminophen is often recommended over NSAIDs due to fewer side effects. Anticholinergic drugs (dicyclomine, hyoscyamine, or oxybutynin) may help reduce cramping.

3. Drainage and Surgery

For abscesses or peritonitis, a small tube is inserted through the skin to drain infected fluid, guided by imaging like CT scans, ultrasound, or fluoroscopy.

It is important to recognize that while surgery can often be beneficial, it doesn’t guarantee the prevention of future episodes or complete symptom relief. Therefore, patients should carefully consider the potential risks and benefits before deciding on surgery.

4. Diet

Diet plays a crucial role in treating and managing diverticulitis, but finding the perfect diet can be challenging due to the complexity of nutrition science. It is difficult to control other variables that may influence outcomes, and self-reporting of what study participants eat may not be accurate or honest. Additionally, the quality of food, including the kind of fats eaten and the diet of the animals providing the meat, can vary greatly and is difficult to control in studies.

One example that shows how study results can be influenced is the source of red meat. Meat from grass-fed cattle has less total fat and more anti-inflammatory omega-3 fatty acids than meat from grain-fed cattle. Conversely, meat from grain-fed cattle contains more omega-6 fatty acids, which can promote inflammation when consumed in excess.

Despite these challenges, we can still draw upon some consistent findings from a 2020 review to guide our dietary choices:

• A high-fiber diet is important for overall gut health, even though evidence for its ability to prevent or treat diverticulitis is inconsistent.
• The Western diet, high in red meat (unprocessed beef, lamb, and pork), refined grains, and fatty dairy, may increase the risk of acute diverticulitis.
• An inflammatory diet, such as the Western diet, can raise the risk by about 30 percent.
• Not everyone benefits from strict diets and resting their bowels after an attack, so it’s important to get personalized advice.
• Trying a low-FODMAP diet, known for helping with irritable bowel syndrome (IBS) symptoms, might also work for managing diverticulitis. FODMAPs are short-chain sugars in foods that the intestine does not absorb well.
• Avoiding nuts, corn, and seeds is not warranted (unless they are a personal trigger) because they are beneficial.

A Clear-Liquid Diet

When researchers compared restricted and unrestricted diets, they found no difference regarding recovery from diverticulitis. However, tolerance and triggers vary greatly by individual. After a flare-up, sticking to clear liquids for a few days may be necessary to help reduce irritation and allow your colon to heal.

Instead, opt for simple and natural clear liquids, such as:

• Water
• Plain coconut water
• Bone broth or other clear broth
• Pulp-free juice
• Pulp-free ice pops
• Gelatin made with juice, tea, or water
• Electrolyte drinks

You can make your own nourishing gelatin using this simple rule-of-thumb recipe:

1. Dissolve 1 tablespoon of unflavored gelatin in 2 tablespoons of cold water.
2. Heat 1 cup of fruit juice to a boil, then combine with the gelatin mixture, stirring until fully dissolved.
3. Pour into a mold or container and refrigerate until set.

For homemade ice pops, you can use the same gelatin mixture; just allow it to cool slightly, pour it into ice pop molds, and freeze until solid.

These homemade options provide a soothing, hydrating treat to enjoy during your recovery. Once you start feeling better, you can slowly begin eating fiber again. Try to eat about 14 grams of fiber for every 1,000 calories, as recommended by the 2020–2025 Dietary Guidelines for Americans.

Some people may find it challenging to transition back to a high-fiber diet. It is important to consider this to avoid triggering another flare-up. However, it is also important not to get stuck in an unhealthy low-fiber phase. If you’re having trouble, talk to a qualified nutrition professional to figure out the best way to do it for you.

The Functional Medicine Approach

Conventional medicine can often be more effective in treating acute diverticulitis cases than promoting prevention. This is where functional medicine may be able to help.

Research on functional medicine is limited due to its relative novelty, the complexity of investigating personalized treatments in clinical trials, and the scarcity of research funding for non-drug treatments. Although specific research on functional medicine and diverticulitis is lacking, some studies suggest the practice can be helpful in other chronic inflammatory conditions such as Type 2 diabetes, obesity, inflammatory arthritis (rheumatoid and psoriatic), and inflammatory bowel disease (IBD).

Living with diverticulitis can significantly affect a person’s mindset and overall quality of life, but there is a lack of evidence that mindset alone can influence the condition’s development. Although there is limited specific research on the direct effects of mindset on diverticulitis, one study showed that patients with a history of diverticulitis have a higher chance of developing mood disorders such as anxiety and depression. This lends credence to the notion that conditions of the mind and conditions of the body interact with one another.

To help keep your gut healthy, it can be beneficial to have a positive mindset. This might mean finding ways to manage stress, practicing mindfulness, and reaching out to friends and family for support.

Eating right, staying active, maintaining a healthy weight, managing stress, and staying hydrated are natural steps toward managing diverticulitis and reducing inflammation. Below are a few examples of anti-inflammatory and pro-inflammatory foods to help guide your dietary choices.

Here are some other natural ways to tackle diverticulitis. Check with your prescriber or pharmacist about interactions with your medications or herbs.

• Keep a food diary to spot triggers.
• Try specific herbs in your cooking or tea. Herbs like chamomile, pennyroyal, fennel, lavender, marjoram, and dill may help calm your stomach and stop it from cramping. Other herbs are anti-inflammatory and antimicrobial, like allspice, bay leaves, black pepper, cardamom, celery, chili, cinnamon, clove, coriander, fennel, fenugreek, celery, dill, nutmeg, poppy, saffron, star anise, and turmeric.
• Skip fizzy or carbonated drinks, which can cause gas and bloating, increasing pressure.
• If coffee or caffeinated tea bothers you, switch to something gentler. Avoiding coffee might also be a good idea if you have diarrhea from antibiotics because it can stimulate bowel movements in some people.
• Choose natural sources of fiber like ground flax or psyllium husk without added sugars or artificial additives.
• Consider using digestive aids. Laboratory studies suggest digestive enzymes or bitters such as gentian root may help your body break down food better, potentially easing symptoms and promoting overall gut health.
• Consider incorporating fermented foods or probiotics into your diet. Some health care practitioners and researchers believe a case can be made for using probiotics due to their ability to regulate the microbiome and because they can be beneficial in treating other gastrointestinal conditions. However, quality research regarding the efficacy of probiotics in treating diverticulitis is scant, so more research must be done to draw firm conclusions.

To prevent diverticulitis, you can take steps to reduce inflammation, manage risk factors, and lead a healthy lifestyle. While factors like age and genetics cannot be changed, there are other things you can control.

Research has shown that following a low-risk lifestyle can decrease the chances of developing diverticulitis by at least 50 percent. This lifestyle includes:

• Eating less red meat
• Consuming a fiber-rich diet
• Exercising regularly
• Maintaining a healthy weight
• Avoiding smoking

Limiting alcohol consumption is also advisable, not just for diverticulitis but for overall gut health, as alcohol can lead to dehydration, slow intestinal motility, and leaky gut.