The Best Diet for Diverticulitis: Splitting Fact From Fiction With Over 25 Studies

This article was originally published on Diet Vs Disease.

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).

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

Note that each section in this article has a 'summary' box (like this one) to save time. Below this box is a contents menu to help you navigate directly to a particular section.

What is 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.

Diverticulitis vs Diverticulosis

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).

What is Diverticular Disease?

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).

Summary: Diverticulitis occurs when small pockets in the lining of the colon become irritated and inflamed. Diverticulosis is simply the presence of these small pockets. Diverticular disease refers to either condition.

Diverticulitis Symptoms

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.

Summary: Diverticulosis is usually symptom-free, however diverticulitis symptoms are typically severe and painful.

Treating Diverticulitis Flare-Ups and Using Antibiotics

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.

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

Summary: Acute flare-ups of diverticulitis are treated with a clear fluid and low-residue diet for several days to allow the gut time to heal. Antibiotics are definitely warranted in severe cases, but less so otherwise.

Diverticulitis and Probiotics

Probiotics are bacteria we eat for health benefits.

Studies show that a variety of different probiotic strains are effective in reducing symptoms of diverticulitis. Particularly those of Lactobacillus casei and Lactobacillus paracasei (7, 8, 9).

In this chart, you can see that a high-fiber diet plus the probiotic Flortec appeared especially useful for short-term abdominal pain (8):

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).

Probiotic Sources

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.

Summary: Research suggests a variety of probiotic strains are effective in managing diverticulitis symptoms. Both fermented foods and supplements are useful sources.

Is It Better to Follow a Low-Fiber or High-Fiber Diet?

Fiber is an indigestible carbohydrate we get from plant foods.

It was always thought that diverticulosis was caused by inadequate fiber intake. However, newer studies suggest it probably doesn’t prevent the diverticula forming in the first place (12, 13).

That said, it most likely does help prevent diverticula becoming symptomatic (diverticulitis).

One observational study found that those who ate 25 grams or more of fiber per day had a 41% lower risk of being hospitalized for diverticulitis compared to those who ate less than 14 grams per day (14).

Another study that followed more than 690,000 women without diverticular disease found that each additional 5 grams of fiber per day was associated with a 15% reduction in risk of diverticulitis (15).

Considering that fiber has numerous other known benefits for health, particularly in maintaining a healthy gut bacteria, it makes sense to recommend a high-fiber diet.

Unfortunately, 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).

Fiber supplements are an option, but whole food sources of fiber are best. This includes legumes, vegetables, fruits and nuts.

The only time a low-fiber diet is recommended is 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.

Summary: A high fiber diet is strongly associated with a reduced risk of developing diverticulitis. Considering the additional health benefits, and overall inadequate intake, more fiber is beneficial for most everyone.

Diverticulitis and Vitamin D

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 (including Crohn’s 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.

Summary: Low vitamin D levels are linked to increased risk of diverticulitis. Get screened for a deficiency with your doctor.

Are Nuts and Seeds Really Foods to Avoid with Diverticulitis?

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.

Summary: Nuts, seeds, corn, popcorn and fruits and vegetables with seeds may be safe to eat with diverticular disease, but the current scientific evidence clashes with patient reports. It might be a good idea to avoid seeds just in case.

What About Red Meat and Diverticulitis?

The idea that red meat intake increases diverticulitis risk is unproven.

It was formed on the back of observational studies that found vegetarians were much less likely to develop diverticular disease than the average person.

A recent study also found that a "Western" dietary pattern (including red meat, refined grains and high-fat dairy) was associated with an increased risk of diverticulitis versus a "prudent" diet high in fruits, vegetables and whole grains (22).

But the reason vegetarian and vegan diets are advantageous is because they're almost always higher in fiber than the typical Western diet. Additionally, non-meat eaters tend to be more health-conscious than the average person (23, 24, 25).

So it’s considerably more likely the benefits lie in eating more fiber, rather than cutting meat or animal foods.

That means you should follow whatever eating pattern will help you eat more vegetables, nuts and other high-fiber foods. If going vegetarian will help you achieve this, and is something you can do long-term, then do that.

Summary: The idea that red meat increases risk is unproven. Vegetarian diets appear protective because they are typically higher in fiber.

Can a Low FODMAP Diet Help Prevent Diverticulitis?

Newer research is finding that a low FODMAP diet may help prevent recurrence of diverticulitis.

In fact, researchers believe that a high-fiber diet with high FODMAPs may be linked with IBS symptoms. Because of this, they recommend a low FODMAP diet for people with diverticulitis as well (26).

Some high FODMAP foods to avoid include:

• Wheat
• Onions and garlic
• Certain fruits, such as apples, peaches and pears
• Certain vegetables, such as asparagus, Brussels sprouts and cauliflower
• Dairy foods
• Legumes

See this Beginner's Guide to the low FODMAP diet for food recommendations and recipe ideas.

Summary: New research shows that following a low FODMAP diet may help prevent recurrence of diverticulitis.

Diet Plan (Menu) For Diverticulitis and Diverticulosis

This is a sample 4-day meal plan or menu for diverticulitis based on recommendations outlined in this article.

But it's certainly also appropriate for the average person with diverticulosis who wants to minimize the risk of getting diverticulitis.

Note that I've modified this to be low FODMAP, as the new evidence strongly indicates minimizing problem FODMAPs is beneficial for diverticulitis patients. A full list of low FODMAP foods and drinks, plus their recommended portion sizes can be found here.

Portion sizes of low FODMAP foods is extremely important, so please make sure you are not exceeding the recommendations. You can also find additional low FODMAP recipe ideas here.

Day 1

• Breakfast: Quinoa Porridge with Berries and Cinnamon
• Lunch: Tuna salad with baby spinach, rocket, tomato and cucumber dressed with olive oil and apple cider vinegar
• Dinner: Tempeh stir fry with veggies (carrot/broccoli heads/Asian greens/veggies working well in stir fries)
• Snacks: Carrot sticks with cottage cheese

Day 2

• Breakfast: 2 eggs (made any way you prefer) on 2 x plain white gluten-free bread + 1 cup of spinach/aragula/rocket drizzled with olive oil and salt.
• Lunch: Last night’s leftovers
• Dinner: Baked or pan fried chicken with low FODMAP roasted veggies
• Snacks: 10 almonds/pecans/walnuts or 20 macadamias

Day 3

• Breakfast: Gluten-free bread topped with cottage cheese and smoked salmon
• Lunch: Low-FODMAP Tomato and Leek Frittata
• Dinner: Chicken/beef/fish (any quantity) +1 tbsp ketchup/BBQ sauce/mustard + 2 small boiled potatoes + ? cup broccoli.
• Snacks: 1 orange or 2 small kiwi fruit

Day 4

• Breakfast: ? cup of oats + 10 raspberries/strawberries/blueberries. Add water and microwave to make warm porridge, or just add lactose-free milk/almond milk for cereal
• Lunch: Low FODMAP Minestrone
• Dinner: Salmon baked in foil in the oven with sliced lime and chilli on top, served with 1/2 cup steamed zucchini and squash, and boiled basmati rice.
• Snacks: 2 rice cakes topped with peanut butter and 1/2 banana

Remember that you may also want to consider vitamin D and/or probiotic supplementation alongside a health eating pattern.

Summary: Treating Diverticulitis with Diet and Food

While a high-fiber eating pattern may not prevent diverticula from forming, it most likely helps prevent the occurrence or recurrence of diverticulitis.

That is, a diet rich in whole vegetables, legumes, fruit, and nuts.

So whichever eating pattern helps you to eat more of these foods – that you still see yourself following in 5 or 10 years - is a great choice.

That said, there is newer research to suggest that following a low FODMAP diet may be beneficial in preventing diverticulitis.

There is also good 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.

Joe is an online dietitian and nutritionist from Sydney. He specialises in weight loss and food intolerance at DietvsDisease.org, which now gets over 1 million readers per month.