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 five years .
This is a research-driven look at what diet changes may help treat diverticulitis, as well as some common myths about foods to avoid.
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 .
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 by researchers. But it appears to be a combination of numerous dietary habits, aging and genetic predisposition .
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.
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
- 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.
Diverticulitis and Antibiotics
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 .
This is where nutrition therapy comes into play.
Summary: 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 ofLactobacillus casei and Lactobacillus paracasei.
In this chart, you can see that a high-fiber diet plus the probiotic Flortec appeared especially useful for short-term abdominal pain :
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 .
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.
Diverticulitis and Fiber
Fiber is an indigestible carbohydrate we get from plant foods.
It was always thought diverticulosis was caused by inadequate fiber intake. However, newer studies suggest it probably doesn’t prevent the diverticula forming in the first place .
That said, it most likely does help prevent diverticula becoming symptomatic (diverticulitis).
One observational study found 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 .
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.
Considering that fiber has numerous other known benefits for the 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 .
Fiber supplements are an option, but whole food sources of fiber are best. This includes legumes, vegetables, fruits, nuts and seeds.
Summary: A high fiber diet is strongly associated with a reduced risk of developing diverticulitis. Considering the additional health benefits, and overall inadequate intake, additional 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, Irritable Bowel Disease (including Crohn’s disease) and diverticulitis .
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 .
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.
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 .
If anything, these foods are more likely to be protective of diverticulitis because they tend to be high in fiber.
Summary: Nuts, seeds, corn, and popcorn are safe to eat with diverticular disease.
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 average person.
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 .
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 to eat more vegetables, nuts, seeds 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.
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, nuts and seeds.
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.
There is 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 no evidence that cutting meat or nuts and seeds from your diet is beneficial. If anything, nuts and seeds are more likely protective.
Remember that diverticulitis is a disease influenced by many other factors too, including obesity, physical activity levels, and smoking status.