Understanding How to Prevent Diverticular Disease

By Frederick Gandolfo MD,

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.

  Filed under: Blog
  Comments: Comments Off on Understanding How to Prevent Diverticular Disease

VIDEO: See how a gastroenterologist does the colonoscopy prep!

By Frederick Gandolfo MD,

In this video, Dr. Gandolfo will show you what NOT to do if you want to have an easier colonoscopy prep experience. He will also share five tips to help you handle the pre-colonoscopy clean-out like a champ!

If you want more information about colonoscopy, be sure to download our free ebook today! It will answer any question you can think of about colonoscopy, even questions you didn’t know you had!

Click the picture of the book below to get it delivered to your inbox!

  Filed under: Colon cancer, colonoscopy, Video
  Comments: Comments Off on VIDEO: See how a gastroenterologist does the colonoscopy prep!

Video: How to prevent colorectal cancer!

By Frederick Gandolfo MD,

March is Colorectal Cancer Awareness Month, but this video holds true all year!

Dr. Gandolfo will review the basics about colon cancer here: What it is, how to prevent it with diet and lifestyle, and how to get screened for this common and deadly disease.

  Filed under: Colon cancer, colonoscopy, Video
  Comments: Comments Off on Video: How to prevent colorectal cancer!

Get Dr. Gandolfo’s free ebook today!

By Frederick Gandolfo MD,

If you’ve got questions about colonoscopy, this is the book you need to read!

Everything You Need To Know Before Your First Colonoscopy is packed with everything you could ever want to know about having a colonoscopy! I will take you step-by-step through the procedure, and answer all of the common questions that I usually get from patients about the test.

Here is the table of contents from the book:

Want a copy of the ebook delivered right now? Enter your email address below, then go check your inbox. Once you click the link to confirm your email address, you will receive the book by email immediately!

Yes, send me the ebook!

* indicates required

Your email will never be shared or sold. It will be used to occasionally send you new articles as I publish them on my informational blog Retroflexions.

  Filed under: Colon cancer, colonoscopy
  Comments: Comments Off on Get Dr. Gandolfo’s free ebook today!

Everyone should know these key facts about colorectal cancer

By Frederick Gandolfo MD,

March is Colorectal Cancer Awareness Month, so I made this infographic to highlight the key facts that everyone should know about colorectal cancer!

For much more about this and other important health topics, please visit my informational site Retroflexions.com!

  Filed under: Blog, Colon cancer
  Comments: Comments Off on Everyone should know these key facts about colorectal cancer

Help! The colonoscopy prep isn’t working! What can I do?

By Frederick Gandolfo MD,

This is an excerpt from a longer article I wrote on Retroflexions.com. You can read the full article here, or you can cut to the chase and just read the important points below…

Bowel prep, or that stuff you need to drink to get cleaned out for your colonoscopy, is never something that one looks forward to doing. You knew that drinking the prep was a necessary evil to ensure a high-quality colonoscopy, but what do you do if you followed all the instructions but the prep simply didn’t work?

If you’re reading this while in the midst of a potentially failed bowel prep don’t despair! There are many ways to salvage a bowel prep and still have a safe, high-quality colonoscopy the next day. It all depends on what time you take action; If you wait until 2 hours before the procedure is scheduled than yes, it’s probably too late to do much. However, if you’re already having issues the night before you can totally recover from this and be fine. This is what I usually recommend, based on the issue at hand:

“I drank the first dose of the prep and nothing happened.” I usually tell patients to wait several hours before panicking. If you have waited 6 hours and there is no bowel activity whatsoever then at that point I would recommend taking either 10 mg of bisacodyl by mouth, or giving yourself an enema. If you’ve done all that and still nothing happens, then it’s probably time to call your doctor and ask for suggestions.

“I drank the first dose of the prep but vomited most of it up.” Unfortunately, you will need more prep then. This usually requires a phone call to the doctor explaining the issue and often an alternative prep is recommended. In selected patients, I would usually recommend Miralax prep or using magnesium citrate instead–both of which can be purchased over the counter.

“I can’t drink the first dose of the prep because it tastes horrible! Yuck!” Try putting the prep in the refrigerator and making it as cold as you can tolerate. Much of the taste disappears when you really chill the prep. You can also call your doctor to see if an alternative prep is an option for you. Ultimately this is also a case of mind-over-matter…it’s unpleasant but sometimes you just have to do it anyway!

“I drank both doses of the prep and my bowels are still not clear” This is a common issues with some bowel preps. It really depends on what time this happens. If you did all the prep the night before, then there is plenty of time to follow the prep with a bottle of magnesium citrate and a large volume of clear liquids. If you notice that you are not clear the morning of the procedure, you can still drink magnesium citrate but really need to finish drinking it about 4-5 hours before the procedure is scheduled to start. This gives it enough time to have an effect, and also keeps you well within the 2 hours safety window for ingestion of clear liquids with respect to receiving anesthesia. However, if the procedure time is close (2-3 hours away)  and you’re still not clear, then the only real option is to give yourself an enema or two. You can always reschedule the procedure if you have to, but realize that you already completed the bowel prep and will therefore have to do the entire prep again if you need to reschedule!

Happy prepping!

  Filed under: colonoscopy
  Comments: Comments Off on Help! The colonoscopy prep isn’t working! What can I do?

Fermented dairy products like kefir may reduce the risk of colon cancer!

By Frederick Gandolfo MD,

Fermented dairy sounds rather disgusting, as the name suggests something akin to spoiled milk, but in reality most fermented milk products are actually quite delicious! Fermented dairy products are foods like yogurt, cheese, sour cream, and kefir among others. The process of fermentation is usually done by bacteria such as Lactobacillus species, and results in a product that is more shelf-stable than milk, while retaining all of the protein and other substances that give milk its healthy reputation. Fermented dairy has been enjoyed by people dating back to about 10,000 B.C., so that trendy kefir stuff you are now seeing at the local food store is really nothing new…

Please click here to read the full article on my informational site ‘Retroflexions.’ 

  Filed under: Blog, Nutrition
  Comments: Comments Off on Fermented dairy products like kefir may reduce the risk of colon cancer!

American Cancer Society recommends colorectal cancer screening to begin at age 45

By Frederick Gandolfo MD,

On May 30, 2018, the American Cancer Society (ACS) released new guidelines regarding colorectal cancer screening for the average-risk individual. The big news is that they now recommend that screening for colorectal cancer begin at age 45 rather than age 50. This reduction in the starting age was in reaction to recent data showing that colon cancer is increasing in younger Americans for unclear reasons. By screening people at a younger age, the hope is that we can detect and prevent colon cancer in more people.

The ACS states that 20% of new cases of colorectal cancer occur in the younger-than-55 crowd. Furthermore, despite a general downward trend in colorectal cancer in the over-50 population, the risk is actually rising slightly in the subgroup of people aged 50-54. These are the cases of cancer the new guidelines are trying to prevent. The ACS is pragmatic in acknowledging that people don’t typically sign up for a colonoscopy exactly on their fiftieth birthday…in fact many wait a few years or more after age 50 to get screened. By pushing the starting age up by 5 years there will likely be a benefit to these patients who would otherwise be late to the colonoscopy party.

The consequences of these recommendations are potentially huge. If these guidelines are followed, an estimated twenty million additional people are now eligible for colon cancer screening. However, the ACS does not specify any one best choice for colorectal cancer screening and states that colonoscopy, stool DNA testing (Cologuard), virtual colonoscopy, and stool testing for occult blood with Guaiac-based tests or FIT testing are all equivalent. I think that by now we know that all tests are not really equivalent, with colonoscopy being the gold-standard test, but with millions of people not getting any type of screening at all, any test is better than nothing.

“My thirties are going great! And in a few short years, I’ll need my first colonoscopy!”

A few caveats about these new recommendations:

  • The ACS states that the recommendation to start screening at age 45 is a qualified recommendation, meaning that there are clear benefits of screening at this younger age but there is less certainty about the exact risk-to-benefit ratio of the recommendation. This is opposed to a strong recommendation, which means the benefit is clear and almost everyone should do it. (Beginning screening at age 50 remains a strong recommendation from the ACS.)
  • Other guideline-producing organizations such as the US Preventive Services Task Force (USPSTF) have not changed their recommendations for colorectal screening, which still remain at age 50 to start.
  • Just because the American Cancer Society changed the recommendation to age 45, doesn’t mean that insurance companies are going to cover the testing! This is perhaps the most interesting part of these new guidelines…who is going to pay for this?
  • Starting screening earlier is definitely going to pick up and prevent more cancers than starting later, however is 45 the best age to start? Surely starting at 44 would pick up even more cancers! I bet starting at 40 would pick up even more than that! What I’m trying to illustrate is how there can be a slippery-slope with these type of recommendations: You will always find more cases of colorectal cancer if you start looking for it in younger and younger people. At what point do the risks of screening more and more people start to outweigh the benefits? Only time and more research will help answer this question.
  • What about the truly early-onset colorectal cancer patients? These are patients diagnosed in their twenties and thirties…how do we detect them before they develop the disease? I doubt anyone will recommend starting routine screening colonoscopies at age 18! This very young onset colorectal cancer may just behave differently than the typical sporadic colon cancer that develops later in life. We need to develop different ways of finding the young patients at risk, and determine why the risk is rising in the younger population.

  Filed under: Blog, Colon cancer
  Comments: Comments Off on American Cancer Society recommends colorectal cancer screening to begin at age 45

A Gastroenterologist Cheats on the Colonoscopy Prep

By Frederick Gandolfo MD,

toilet paper

I’ll just start out by letting you know that I had mixed feelings about posting this. Not because I’m embarrassed to publicly discuss my colonoscopy experience (weirdly enough, I am OK with that part), but because I don’t want to be responsible for people interpreting what I’m about to disclose far too liberally and ruining their pre-colonoscopy cleanout. So please read on, but don’t push the limits too much. Failing to achieve a good bowel prep will require you to repeat the exam and prep again, and nobody wants that to happen!

For the past year or so I have been having minor IBS-type symptoms on and off, mostly related to stress or periods of poor diet. As a gastroenterologist, I started getting into my own head and worrying that I had some rare or catastrophic disease (the availability heuristic is real!) Part of me knew that if the test was normal, I would probably feel better just with that knowledge alone. I’d also be lying if I said that I wasn’t just a little curious about the whole process too. I either talk to people about colonoscopies or perform them for most of my waking hours; shouldn’t I also have some first-hand experience to reference for my patients?

So I scheduled a colonoscopy and requested Suprep bowel prep. I choose Suprep because it is what I usually give out to patients…I’ve noticed that most people seem to complain the least about the taste of Suprep when compared to most other preps. That’s not to say that the other preps are inferior…I use them interchangeably. However, I wasn’t about to get two or three more colonoscopies just to test out all the preps, so the Suprep experience is what you get to hear about!

suprepI was given the usual instructions for split-dose bowel prep: 1) Clear liquids only the entire day prior to the procedure; 2) Take the first dose of prep at 5 PM and the second dose of prep 5 hours before the procedure start time; 3) Nothing to eat or drink after the second dose of prep. Pretty standard stuff, these are the instructions I usually give to my patients. Following this will lead to a good or excellent bowel prep in the vast majority of people. But what if I told you that I did something different but still achieved an excellent clean-out?

toasterI cheated on the prep. I ate solid food the day before. Now before anybody gets too excited, I ate a very limited and small amount of food, but it made a huge difference in the ability to tolerate the entire process. The following is my “justification” for my cheating, other than the obvious reason of “I was hungry.” I wake up around 5:00 AM or earlier every day. I usually wake up starving and if I don’t eat something within an hour or so of waking I usually feel weak and like my head is spinning. I’ve been this way as far as I can remember, even back in elementary school. I had a long day ahead of me at work, and knew that without some calories in me I would crash in the mid-morning while doing procedures and not be able to function well. “It’s for the patients,” is what I told myself. I almost believed it, too!

So that morning I ate a good-sized bowl of plain vanilla yogurt (no toppings, nuts, fruit, etc.) I also had a few pieces of white toast with butter. We usually don’t have white bread in the house, but we were lucky to have an unseeded loaf of Italian bread from the night before that I toasted in the toaster and buttered up. For lunch, I had a huge gelato without any nuts or toppings. Throughout the day I drank black coffee and plenty of clear liquids.

ice creamI got home around 6PM that day (a little later that the recommended 5PM start time) and began drinking the prep. I mixed the first part of the prep with water as recommended and took a sip. Thinking that I’d be really slick, I used a straw to try and bypass my taste buds. “Not terrible,” I thought to myself, relieved that this process wasn’t going to be as bad as many patients made it sound. The prep tasted like a mixture of seawater, dish soap, and grape cough syrup…yum! A few sips later and I was rethinking this whole thing…the cumulative effect of drinking the prep made each sip taste grosser than the last. After drinking about one-quarter of the first 16 ounces of the stuff, I put the container in the fridge and took a 10-minute break to pace around the house and rethink my strategy.

Going back to the prep in the fridge, I took a few more sips through the straw. Why was it taking so long to drink this stuff? If this were water I could have drank the whole thing in five minutes. I think the straw is actually slowing the process down. I ditched the straw and was able to drink the prep much faster. A few gulps later I was half-way done with the first round. I put the container back in the fridge since the colder the prep was the less bad it tasted. It’s now about 6:20 PM and I suddenly felt a strange grumbling in my lower abdomen.

I was surprised at how fast this stuff works! I figured it would take an hour or so to have any effect, or at least give me some warning first. I was wrong on both counts! With 8 oz. of the nasty stuff down so-far, I was lucky that my bathroom was only a few steps away! Immediate watery diarrhea was the result. The thing I wasn’t expecting was the total lack of pain, cramps, or any discomfort whatsoever. It was as someone just opened the faucet, then closed it again. Magic!

I finished the rest of that evening’s prep over the following 20-30 minutes in between several other sprints to the bathroom. The prep was definitely easier to drink when cold straight out of the fridge. It was about 7PM and the bowel movements were coming fast and furious now. I also noticed that I was incredibly thirsty all of a sudden. I chugged 32 ounces of room temperature Gatorade in about five minutes flat. I wanted more, but only had tomorrow’s ration in the house. Therefore I drank a glass or two of water. By 9PM, all was quiet. I mixed tomorrow morning’s prep and put it in the fridge to chill overnight. I woke from sleep around 1AM for one more small bowel movement, but it was no big deal. I actually got decent sleep.

The next morning, I woke up at my usual time of 5AM. I drank 2 cups of black coffee as soon as I woke up. This was followed by another 16 oz. of Suprep over the next 45 minutes. I would gulp down about 4 oz. at a time, then rest for 10-15 minutes and repeat until done. This time, the bowel movements started immediately after taking the first bit of the prep and were mainly yellowish water. Another 32 oz. of Gatorade down the hatch and the process was complete. The last 2-3 bowel movements were literally clear water, like as clear as the water that comes out of the faucet. Cool, I did it!

Now would be a good time to talk about a study from a few years back. Thinking that improving the tolerance of the prep would remove one of the classic barriers for some people to do colonoscopy as well as decrease the number of broken appointments and inadequate preps, researchers randomized patients into two groups: One group received a clear liquid diet the entire day prior, and the other was able to eat a light breakfast and lunch with several food restrictions the day prior. Both groups then completed the standard bowel prep. The study showed exactly what we would expect: The people who starved all day were miserable, the people who ate a little were less miserable, and the quality of the bowel preps achieved were the same between the groups! The most interesting finding was that the group of patients who were restricted to only having clear liquids cancelled their appointments more than twice as frequently as the patients that were allowed to eat just a little. Hunger is a powerful force to compete with!

Now before you eat a bacon cheeseburger with fries, corn on the cob, and a salad the day before your colonoscopy, it’s very important to understand that these subjects (and yours truly) ate a very limited diet the day before the colonoscopy. Fibrous foods such as any fruits or vegetables are not allowed. Seeds, nuts, whole grains, fresh or dried herbs/seasonings, popcorn, and the like are definitely not allowed. Corn is probably the worst thing one can eat the day before having a colonoscopy!

no cornWhat kind of foods are OK to eat the day before the colonoscopy? Low residue foods (low roughage) are ideal; these are processed flours (white bread, etc.), white rice, pasta, yogurt, gelato, and related snacks, eggs, lean meats, and other foods. A light breakfast is fine. A light snack around lunch time is OK too, but after that it’s clear liquids only. That means “dinner” is clears only: You don’t want food and bowel prep in your stomach at the same time, trust me.

So back to the title of this article: A gastroenterologist cheats on the colonoscopy prep and wins! Did I really cheat? I guess not, since it seems that research backs up what I did! But did I win? Can you ever call getting a colonoscopy “winning?” I guess it depends on the findings. I did, however, have an excellent bowel prep!


  Filed under: Blog, colonoscopy
  Comments: Comments Off on A Gastroenterologist Cheats on the Colonoscopy Prep

What Causes Colon Polyps?

By Frederick Gandolfo MD,


When it comes to colon cancer prevention, the polyp is the key player to know. Colon polyps, called adenomas, are precancerous growths originating from the inner lining of the colon wall. There are other types of polyps in the colon which are not considered precancerous, but for our purposes in this article we will consider the terms colon polyp and adenoma to be one and the same.

Polyps are important to know about because they are the precursors to colon cancer. That is, virtually all cases of colon cancer began many years earlier as a small polyp growing in the colon. For the average person, it takes many years for these small polyps to appear on the scene, which is why we don’t usually recommend colonoscopy until a person is 50 years old. However, it’s not totally uncommon to find significant-sized polyps in younger people in their 30s or 40s (and even in their 20s!) From the time a polyp starts growing, it is thought to take more than 10 years for the polyp to grow into cancer…and not all adenomatous polyps grow larger or turn into cancer at all. However, many polyps will continue to have cellular changes such as mutations that will promote growth of the polyp and eventually transformation into colon cancer.

By understanding what causes colon polyps, we can understand what causes colon cancer. Here are some risks factors for getting colon cancer/polyps that an individual cannot change:

  • Age: The risk tends to go up as one gets older.
  • Sex: Men seem to have a slightly higher chance of having polyps when compared to women.
  • Family history: A close relative with polyps or colon cancer makes your risk go higher.
  • Race: Black men and women have the highest risk of developing colon cancer.

However, roughly half of all cases of colon cancer (and by extension, colon polyps) are a result of modifiable risk factors. These are the things that you can control. If we know what these risk factors are, maybe we can make better choices for ourselves and our families. The following is a list of the known risk factors for developing colon cancer/polyps:

    • Alcohol: Alcohol use is closely tied to colon cancer risk. Unfortunately, even for “social” drinkers, the risk goes up by about 10% if you only drink less than 1 drink per day. If you have 2-4 drinks per day, the risk increases by 23%!


    • Red meat: Beef, veal, lamb and pork (despite the advertisements) are considered red meats. Regular consumption of about 100 grams of red meat per day (about the amount found in 2 regular-sized McDonald’s hamburgers) can increase the risk of colorectal cancer by 17%. I like the idea of “everything in moderation” so let’s aim to only eat red meat about once per week.
    • Processed meat: This seems to be a real bad one…processed meat is often also red meat and is defined as meat that has been salted, cured, smoked, fermented, or treated with other processes to improve flavor or preserve the meat. Processed meat is bacon, sausages, hot dogs, cured ham, etc. The risk of colorectal cancer goes up by 18% for those who eat just 50 grams per day of processed meat (this is half the amount of red meat needed for the same risk).

processed meat

    • Lack of dietary fiber: Eating fiber is good for your colon for many reasons, and transmits a decreased risk of colon cancer as well. An extra 10 grams of fiber in the diet can drop colon cancer risk by 10%, but don’t stop there: Men should get 38 grams of fiber per day, and women are recommended to eat 25 grams per day. An apple has about 4 grams of fiber in it, so that’s a lot of apples to eat every day! Alternatively, you should eat a variety of plant-based foods and take in fiber with each meal and snack.


    • Smoking: This seems obvious. Smoking causes all kinds of cancer. It also increases the risk of colon polyps and colorectal cancer. Smoking is not a great way to stay healthy.
    • Obesity: Being overweight or obese increases the risk of colon cancer. This is independent of physical activity. That is, the excess weight itself seems to be tied to cancer risk, likely due to changes in inflammatory and growth signaling molecules, among other factors.
    • Lack of exercise: Interestingly, staying physically active can reduce the risk of colon cancer by a whopping 25%! The minimum amount of exercise recommended for this purpose is about 2.5 hours per week of moderate exercise, or 75 minutes per week of intense exercise, but more is better. Again, the reasons for this are somewhat unclear but likely rooted in positive changes in insulin resistance, growth factors, inflammatory factors, and who knows what other things that are modified by exercise. We weren’t born to sit around, going from couch to car to chair and back again…we were born to move, so do something active on a regular basis!


  • Coffee: Well this should really read “lack of coffee” because coffee seems to be somewhat protective against developing polyps and colon cancer! There are not many high-quality studies on this topic, but what is out there suggests a 25% decrease in colorectal cancer with coffee consumption, possibly due to the antioxidants found in coffee.
  • Calcium: This is controversial. On one hand it seems that high consumption of dairy products like milk is associated with a lower risk of colorectal cancer. At best, supplementing calcium seems to have no effect on cancer risk for better or worse. However a very recent study suggests an increased risk of adenomatous polyps from taking both calcium and vitamin D supplements in combination, so more research will be needed to figure out the exact role of calcium, vitamin D, and the combination of both for colon cancer prevention.

And let’s not forget the final factor that leads to colon polyps and cancer in many individuals:

  • Bad luck: Unfortunately some people just have bad luck. We doctors don’t understand everything! This is why it’s still important to get screened for colorectal cancer at the appropriate age even if you don’t have any family history or symptoms, and are a thin, non-smoking, vegan, fitness-guru teetotaler!

  Filed under: Blog, Colon cancer
  Comments: Comments Off on What Causes Colon Polyps?