Diverticulitis is an extremely unpleasant digestive disease.

Those diagnosed know it’s worth taking measures to avoid future episodes. Unfortunately, 1 in 5 will have another flare-up within 5 years (1).

Research has accelerated a lot in the past decade, with the latest indicating triggers are thought to involve certain diet and lifestyle factors, alterations in the gut microbiome, genetics, and more (27, 28).

This article is a research-driven look at what diet changes may help treat diverticulitis, as well as some common myths about what foods to avoid with diverticulitis.

Diverticulitis occurs when small pockets in the wall of the large intestine (colon) become inflamed or infected.

These small pockets or sacs – called diverticula – are formed when the muscles of the colon become too weak in certain areas. This causes them to push outward and form a “pocket,” which is common in the lower part of the colon.

Diverticulitis becomes extremely painful during a flare-up. Even immediate surgery can be required to treat a severe case.

Diverticulosis refers to having diverticula that have not yet become infected and painful.

This means diverticulosis always occurs before diverticulitis.

‘Osis’ refers to a medical condition, while ‘itis’ typically refers to inflammation or infection.

The risk of diverticulosis increases as we grow older, to about 70% of people aged 80 and above. Fortunately, it only progresses to diverticulitis about 4% of the time (2, 3).

Together, diverticulitis and diverticulosis are often referred to as diverticular disease.

The cause of this disease is complex and still poorly understood. Researchers suspect it to be a combination of numerous dietary habits, aging and genetic predisposition (4).

Most are unaware they have diverticulosis until it becomes infected and painful (diverticulitis).

Symptoms can vary between individuals, but the most common are:

● Ongoing constipation
● Ongoing diarrhea

● Tender abdomen

● Cramping or bloating

● Fever

● Extremely painful bowel movements

● Blood in stool

● Nausea and vomiting.

Diagnosis is based on a history of symptoms in addition to some medical tests.

This can include blood tests, a colonoscopy or radiology as determined by your doctor.

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Diverticulitis typically occurs as a painful “flare-up” with sharp pain and digestive symptoms.

It’s not uncommon for treatment to require a hospital admission, where the diet is heavily modified to allow the digestive tract some time to heal and inflammation to subside.

This includes a clear fluids diet for several days followed by a short-term “low-residue” or low-fiber diet and eventually progressing to normal foods.

In severe cases of diverticulitis, surgery and regular antibiotic use are required to overcome the infection. However, recent research suggests that aggressive antibiotic treatment is overused, particularly in less severe cases (5, 6).

This is why diet and nutrition are incredibly important for managing this disease, not only during a flare-up but afterwards as well.

Below you can see a diagram of what the latest research indicates are the causes of diverticulitis (27).

The remainder of this article focuses on long-term dietary management of diverticulitis.

Probiotics have also been successfully combined with the anti-inflammatory drug Mesalamine to help reduce symptoms of diverticulitis. However, it’s uncertain if they reduce the risk of recurrence (10, 11).

The best food sources of probiotics are fermented foods, such as yogurt, quark, Yakult, sauerkraut, kefir, kimchi, tempeh, and miso.

Probiotic supplements are also a great option, but recommended strains and dosage have yet to be determined. Always buy probiotic supplements (as with any supplement) from a reputable and trusted source.

Considering that fiber intake has other known health benefits, such as promoting regularity of bowel movements and maintaining a healthy gut bacteria, it makes sense to recommend a high-fiber diverticulitis diet.

Additionally, today most people only consume half of the recommended amount. Women should aim to get at least 25 grams per day, while the average man should have at least 38 grams per day (16, 17).

However, with that said, there is no reliable evidence that a high-fiber diet improves symptoms or prevents complications in diagnosed cases of diverticulitis.

A recent review of 19 studies (9 looking at dietary fiber, 10 at fiber supplements) was unable to make any firm conclusions because each study varied so greatly in how they were conducted, the type and amount of fiber used, among other things (27).

The authors’ conclusions were:

So there is no definite answer, which helps explain why the Danish and Polish guidelines recommend fiber supplements, whereas the Italian guidelines argue somewhat the opposite (28).

Basically fiber supplements are an option, as is a high-fiber diet, but unfortunately a bit of trial and error is the only way to see what sits better with you. Many people report doing better on a low fiber diverticulitis diet, which overlaps heavily with a low FODMAP diet (more on that below).

And as mentioned above, a low-fiber diet is definitely recommended following a flare-up. After a few days on a clear fluids diet, you can progress to boiled and soft foods, including cooked fruits and vegetables (without skins), as you slowly increase your fiber intake.

Tap the blue button below to download our FODMAP “Eat This, Not That” list as well as additional resources for diverticular disease (it’s free!)

Vitamin D is a critical nutrient for human health, best known as the “sunshine vitamin.”

There is increasing evidence that our vitamin D status may influence risk of gastrointestinal diseases such as Irritable Bowel Syndrome, Inflammatory Bowel Disease and diverticulitis (18).

A recent study in those with diverticulosis found those with the lowest vitamin D levels were significantly more likely to experience a diverticulitis flare up (19).

So it’s important to have your vitamin D levels checked with your doctor, particularly if you don’t get much regular sunlight exposure.

Unfortunately, natural food sources of vitamin D are not very useful if you have a deficiency. This is one of the few instances where supplementation is far superior to food.

A simple search for “foods to avoid with diverticulitis” or “what not to eat for diverticulitis” will show you nuts and seeds, corn and popcorn.

You will also find recommendations to avoid seeds in fruits and vegetables like tomatoes, zucchini, cucumbers, strawberries and raspberries.

In fact, for years we’ve been taught these foods can literally get stuck in diverticula, causing irritation and eventually diverticulitis.

But this theory has never been proven, and research actually shows no link.

A large study in 47,228 men found no associations with nut, corn, or popcorn consumption and diverticulitis, after 18 years of follow-up (20, 21).

In saying that, anecdotal evidence (patient reports) consistently suggests that seeds are an issue, such as sesame seeds on a bread roll.

So evidence is really a mixed bag, it might be better to err on the side of caution and avoid seeds at least. I wish I could give a more concrete recommendation but there really is no consensus at this stage.

There is no doubt that fiber is good for you, and that a high-fiber eating pattern may help prevent diverticulitis occurring in the first place

However, there is very little evidence it helps minimize symptoms in those who have already been diagnosed.

In fact, newer research suggests that following a low FODMAP diet may be the most beneficial in preventing diverticulitis from recurring (as demonstrated above).

There is also some evidence that probiotics (particularly some strains of lactobacilli) are useful for treating symptoms. However, researchers are unsure they help prevent recurrence.

Also consider vitamin D supplementation if you have low levels.

Lastly, there is little evidence that cutting meat or nuts and seeds from your diet is beneficial. If anything, nuts are more likely protective, while seeds are still a bit of a mystery.

Still, each person’s experience is different. You may find that certain foods worsen your symptoms and are best avoided.

Remember that diverticulitis is a disease influenced by many other factors too, including obesity, stress, physical activity levels and smoking status.

I hope this article cleared up some of the confusion for you. Please contact us if you would like any further help.

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