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Understanding How to Prevent Diverticular Disease

man holding stomach in pain

Diverticular disease is the term that covers both diverticulosis and diverticulitis. While almost everyone has heard these terms, many people still mix up the difference between diverticulosis and diverticulitis. Furthermore, there is a lot of misinformation out there regarding these common conditions, so it’s time to review what is new in the world of diverticular disease!

Let’s start with some basics: The tiny pockets that occur on the outside of the colon that we call diverticula are actually better described as pseudodiverticula (false diverticula) due to the fact that they only contain the inner two layers of the colon wall, called the mucosa and submucosa.

These inner two layers that form the lining of the bowel become pseudodiverticula by herniating through small natural weak points in the muscle layer of the colon. The weak points exist as natural openings where small blood vessels called vasa recta penetrate the bowel wall to feed blood to the inner layers of the colon. For various reasons that we will cover below, the inner mucosal and submucosal layers of the colon can pop through these openings and luckily will become contained by the outermost layer of the colon (called serosa) to form a small pocket, now called a diverticula.

Since pseudodiverticula is a mouthful, people just refer to these pockets as diverticula. The condition of simply having these small pockets is called diverticulosis.

Diverticulosis is typically asymptomatic, but can also cause several symptoms. Minor symptoms of constipation and chronic left lower abdominal discomfort may be related to diverticulosis and are thought to be caused by altered colon motility (loss of normal movement), narrowing of the colon, loss of compliance (lack of “stretchiness”) of the left side of the colon, and mild inflammation of the bowel in the affected area. The symptoms of diverticulosis often overlap with symptoms of a condition called irritable bowel syndrome (IBS).

The more severe complications of diverticulosis are diverticular bleeding and diverticulitis.

Diverticular bleeding is typically painless and may present as massive bleeding. Fresh red blood is usually passed from the rectum as one of the small penetrating vasa recta arteries ruptures and bleeds into the bowel lumen (inside the colon). Diverticular bleeding often results in hospitalization, and may require blood transfusion and/or procedures to control bleeding such as colonoscopy, angiography with embolization, and even surgery if the bleeding does not stop. Fortunately, most cases of diverticular bleeding are self-limited, that is, the bleeding stops on its own and the treatment mainly consists of supportive care.

Diverticulitis is the term used to describe inflammation of a diverticula and the surrounding segment of colon. This is typically quite a painful process and is often associated with a fever, sometimes constipation, and decreased appetite. The abdominal pain from acute diverticulitis is often present in the mid lower abdomen, the left lower abdomen, or a combination of both of these sites.

Laboratory testing in acute diverticulitis will often reveal an elevated white blood cell count and elevated inflammatory markers such as C-reactive protein (CRP). A CT scan of the abdomen and pelvis is the diagnostic test of choice, and will reveal a thickened and inflamed bowel wall, often with inflammatory changes extending outside the bowel wall into the surrounding fatty tissues, and possibly with evidence of “microperforation” or other complications. Treatment typically involves antibiotics, bowel rest or a limited diet, and local management of any complications (such as draining an abscess). Eventually surgical resection may be needed in cases of complicated or recurrent diverticulitis.

Now that we have reviewed the basics, I would like to cover some of the common questions that I get asked by patients about diverticular disease.

How did I get diverticulosis?

Diverticulosis is often though of as a disease of Western society, and is associated with several diet and lifestyle factors. Most notably, diverticular disease is associated with a low-fiber diet, a diet high in processed foods and red meat, a sedentary lifestyle, obesity, and smoking.

However, diverticular disease also has a genetic component. It is likely that genetic factors and lifestyle factors both play a role in developing diverticular disease.

Age is also a factor: The older you become, the higher the likelihood that you will develop diverticulosis!

Is there a special diet to follow for diverticulosis?

Yes! To prevent diverticulosis, you should eat a high-fiber diet of mostly plants, whole grains, and legumes. A high-fiber diet means about 30 grams of fiber a day for women, and about 35 grams of fiber a day for men, but more is better (to a point).

However, a high-fiber diet is not the whole picture! It is also important to eat anti-inflammatory foods such as seeds, nuts, fish, and olive oil! Diverticular disease is an inflammatory process, and foods like red meat, processed meat (bacon etc.), and processed carbs (sweets, snack foods, fast foods, etc.) are pro-inflammatory and can cause issues like diverticulitis to occur more frequently.

Can I eat seeds and nuts if I have diverticulosis?

Yes you can! It is not necessary to avoid seed and nuts if you have diverticular disease. Probably the best evidence we have that seeds, nuts, corn, and popcorn do not cause complications in patients with diverticular disease comes from a study published in JAMA in 2008 showing that not only was intake of nuts, seeds, popcorn, and corn NOT associated with developing diverticulitis, but in fact the opposite was true. Eating more seeds, nuts, corn, and popcorn actually seemed to be associated with LESS of a chance of developing diverticulitis! These foods are thought to be somewhat anti-inflammatory, and therefore may protect against diverticulitis.

What other lifestyle factors should I consider if I have diverticulosis?

The big four things to consider with diverticular disease (and every other disease) are smoking, alcohol use, obesity, and exercise.

Smoking: Bad in every way and increases inflammation throughout the body. Smoking is associated with diverticulitis. Smoking is also associated with poor wound healing after surgery. Don’t do it! (If you’re serious about quitting, ask your primary care doctor for help.)

Alcohol: Not great for your colon and can sometimes cause inflammation in the bowel. To be enjoyed sparingly.

Obesity: Associated with total-body inflammation and correlated with diverticular disease. Increases risk of surgery if needed for diverticular disease. (If you suffer from obesity, the best time to start working on your weight was 10 years ago, and the second best time is today! Check out my simple starter plan here.)

Exercise: Aside from the role of exercise in weight loss, exercise also promotes a healthy colon, and can help keep your other healthy lifestyle changes in check by creating a positive-feedback cycle. Try to do a little exercise every day, or at least four days a week!

Does diverticulosis ever go away?

No, not really. Once the pockets are there, they don’t regress and disappear. They’re similar to wrinkles in that way. However, the goals are to prevent new diverticula from forming and to prevent the pockets that are there already from worsening or developing complications such as diverticulitis.

Following a healthy diet and lifestyle is still important, even if it won’t turn back time and remove the diverticula from your colon! In fact, it is estimated that you can reduce your risk of developing diverticulitis by up to 75% by following the basic diet and lifestyle advice above!

New knowledge about diverticular disease

“Old School”“New Knowledge”
Diverticulosis is caused by constipationDiverticulosis may be associated with constipation but no causative role has been established
Diverticulosis is caused by a lack of dietary fiberDiverticulosis is related to a low-fiber Western diet, but fiber may not be the most important factor
Seeds and nuts are dangerous and should be avoided!Eat as many seeds and nuts as you want. The more the better actually!
Diverticular disease affects elderly people onlyDiverticular disease is common in young people (especially men) and the prevalence is rising!
Diverticular disease just happens to people randomlyThere is a strong genetic predisposition to diverticular disease. It might be your parents fault!
Diverticular disease is due to small pockets herniating through the colon wall, a purely mechanical process due to high pressures in the colonDiverticular disease is an inflammatory condition, and there are chronic cellular changes found throughout the entire colon wall
Lifestyle and diet are not associated with diverticular diseaseThe Western diet and lifestyle (obesity, smoking, high red meat intake, alcohol use, and physical inactivity) dramatically increases the risk of diverticular disease!


Diverticulosis and diverticulitis are very common diseases. Many people have mild cases of diverticular disease and never need medical attention, but there are several common complications of diverticulosis that do require medical attention and can be quite dangerous.

Overall, the paradigm is shifting and we are beginning to think of diverticular disease as a type of inflammatory condition with a genetic predisposition, rather that purely a mechanical problem related to constipation and high pressures in the colon.

Following a healthy diet and lifestyle can dramatically reduce your risk of suffering complications from diverticular disease, so make sure to eat your vegetables, limit processed foods and red meat, get a little exercise every day, stop smoking, and work on maintaining a normal body weight.

Can you eat seeds, nuts, and popcorn if you have diverticulosis? Can diet prevent diverticulitis?


Diverticulitis is a common and sometimes serious problem that affects several hundred thousand people each year. Diverticulitis is the condition where small outpouchings or “pockets” in the wall of the large intestine called diverticula become inflamed and infected, and typically presents as a constant lower abdominal pain, associated with fever or chills, and often bloating or constipation symptoms. Despite becoming even more common in recent years, not much is understood about why diverticulitis occurs.

Diet has long been implicated in the formation of these diverticula which can eventually become inflamed leading to diverticulitis (the condition of just having the pockets without an associated infection/inflammation is called diverticulosis). We know that diverticular disease is rare in countries where fiber intake is high, and we know that when populations change to a more westernized diet (poor in fiber/rich in protein, fat and processed sugars) the rate of diverticular disease rises accordingly. So if fiber is protective against developing diverticular disease in the first place, does it stand to reason that supplementing fiber when one already has diverticulosis will help prevent future complications?

The answer to the above question is unknown, but because fiber is a mostly harmless supplement and has other health benefits, we often recommend fiber supplementation to patients after they are diagnosed with diverticulosis or diverticulitis. But what about the common advice of avoiding seeds, nuts, corn, and popcorn that is readily doled out by some doctors and most family members/friends as soon as they hear the words diverticulosis or diverticulitis? One can reason that it makes common sense to try to avoid having sharp, hard, indigestible seeds getting stuck in a diverticulum and causing an abrasion or perforation which may lead to infection and other nastiness. But does this recommendation have any valid scientific reasoning behind it?

While I’m not sure when or where this recommendation started, it probably belongs more under the category of “old wives’ tale” rather than scientific fact. Let me explain my reasoning for this:

It is very commonly observed during colonoscopy that patients with diverticulosis are found to have a small ball of stool impacted in each and every diverticulum. Presumably, this is the natural state of affairs in the colon of the patient with diverticulosis. So if small hard pellets of stool (mostly composed of indigestible waste and bacterial mass) do not cause an infection, why would a small seed or nut cause a problem? Nevertheless, people still take great pains to avoid seeds, nuts, and corn, causing themselves a fair amount of grief when it comes to meal options. Is this all worth it?

I would reason that it is not necessary to avoid seed and nuts if you have diverticular disease. Probably the best evidence we have that seeds, nuts, corn, and popcorn do not cause complications in patients with diverticular disease comes from a study published in JAMA in 2008 showing that not only was intake of nuts, seeds, popcorn, and corn NOT associated with developing diverticulitis, but in fact the opposite was true. Eating more seeds, nuts, corn, and popcorn actually seemed to be associated with LESS of a chance of developing diverticulitis! These foods are thought to be somewhat anti-inflammatory, and therefore may protect against diverticulitis.

So what is the ideal diet to prevent development of diverticular disease? I think it is pretty obvious that a high-fiber diet is king in preventing the development of diverticulosis. But what if you are late to the high-fiber party but still want to make some changes to prevent that next attack of diverticulitis? Starting a high-fiber diet later in life may still help to reduce the progression of more diverticula, but unfortunately there is no way to reverse the existing diverticula (besides surgical resection of the diseased segment of colon). However, there are still diet changes you can make that might help.

It seems that diets high in red meat are also associated with the development of diverticulitis. This is independent of the effect of fiber, as red-meat eaters develop diverticulitis more often than their vegetarian counterparts even after controlling for fiber intake between the groups. What is more interesting is that researchers found that the recent diet for the past 1-4 years before developing diverticulitis seemed to shape the risk more than the lifelong diet habits. That means that changing to a high-fiber, low-red-meat diet now can still lessen your chance of developing diverticulitis in the near future. But look at the bright side–at least you can eat all the seeds, nuts, corn, and popcorn you want!