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Cologuard® vs. Colonoscopy: Which test is better?

Doctor about to perform colonoscopy

In the US, colorectal cancer is currently the second leading cause of cancer deaths in men and women combined. Virtually all health professionals agree that screening average-risk people starting at age 45 for colorectal cancer is the best way to prevent this disease. There are a few highly effective tools available for colorectal cancer screening: This article will focus on the two most popular tests, colonoscopy and the Cologuard test.

Most people are familiar with colonoscopy, but in case you’re not…colonoscopy is a safe 15-20 minute outpatient procedure that is done using sedation (so it’s painless) that entails using a flexible scope inserted in the rectum (the end part of the colon) and carefully advanced to the cecum (the other end of the colon) to inspect the entire colon lining for the presence of polyps, tumors, and other abnormalities. A polyp is a “precancerous” growth that is common and if not removed can slowly grow and eventually may turn into colon cancer. During a colonoscopy, the doctor can both find polyps and remove these polyps at the same time. Therefore colonoscopy can both diagnose cancer and polyps, but more importantly colonoscopy can prevent colorectal cancer from occurring in the first place by removing precancerous polyps years before they would have otherwise become cancer. A normal colonoscopy typically does not need to be repeated for 10 years. If polyps are found and removed, a colonoscopy will be recommended sooner, to make sure any new polyps that grow will be found and removed before having a chance to turn into colon cancer. Colonoscopy is considered the gold-standard colon cancer prevention test and is the preferred test by most medical societies.

Image of colonoscopy with polyp removal.

Cologuard® is a non-invasive, commercially-available screening test for colorectal cancer. The test is ordered by a doctor (typically a primary care provider) and mailed to the patient’s house. When the urge to have a bowel movement strikes, the patient places the Cologuard collection device over the toilet and makes a deposit. There are a few simple preparation steps such as adding in a small amount of liquid that the company provides, and then the entire container of poop is mailed back to the company in the provided packaging. The Cologuard test looks for blood and certain DNA mutations in the stool to determine if a test is positive or negative. A week or so later the doctor gets a report indicating the result. If the test is negative, it only “protects” the patient for 3 years.

So which test is better, colonoscopy or Cologuard?

Well, it really depends on what the goals are…

As a general philosophy, it’s much more effective to prevent a disease from occurring rather than waiting for the disease to occur, then reacting to it. When the disease in question is colon cancer, preventing it starts with healthy diet and lifestyle as well as screening the population at large for polyps, the precancerous growths that cause colon cancer. To have a colonoscopy and remove a significant polyp is akin to stopping a future cancer from occurring in the first place. When effective preventive tests like colonoscopy exist, to wait until a patient has developed cancer and then treating the cancer is like waiting until you have been in a car accident to then put on your seatbelt…it’s too late. Although there are excellent treatments available for colorectal cancer nowadays, including surgery and chemotherapy, treating cancer is not the goal of screening. The goal of screening is to not develop cancer of the colon in the first place!

Typically, when an effective prevention technique exists (like removing precancerous polyps during colonoscopy) the earlier we can screen for colon cancer the better. This is why colonoscopy is the preferred test for younger healthier people starting at age 45. Save a 45-50 year old from colon cancer and you will potentially give that person 30-40+ years of life having not developed colon cancer. Saving a 79 year old from colon cancer is still a commendable goal, however the average 79 year old typically won’t have as many quality years left “in the tank” compared to the average 45 year old.

So why does this philosophical stuff matter when it comes to picking a colorectal screening test? Well, understanding what these tests do helps you understand how to apply the proper test to your individual goal.

If this article is already too long and you just want the bottom line, here it is: Colonoscopy is the superior test for most people, especially “younger” people (age 45-mid 70s). It can both detect and (more importantly) prevent colorectal cancer. It is semi-invasive and less convenient when compared to Cologuard testing. Cologuard is an easier test but plagued by false negatives and false positives. Cologuard does not necessarily prevent cancer, it only detects cancer after cancer has occurred, or at best detects large polyps that are close to becoming cancer. Cologuard should be considered for older patients (age 75+), for patients that may not have the best overall health, or for patients who have specific reasons why they cannot have a colonoscopy.

OK, you asked for it! Here are more details, starting with the Cologuard test:

The study that determined the characteristics of the Cologuard test basically performed the test on almost 10,000 patients at average-risk of colon cancer, and then had the patients undergo colonoscopy as the gold-standard test. The results of the Cologuard test were not available to the patients or the endoscopist at the time of the colonoscopy. The major results of this study showed that the Cologuard test had a sensitivity (the amount of times it picked up colorectal cancer when cancer was indeed present) of 92%. It was far less sensitive for picking up advanced precancerous polyps, at only 42%. It turns out that sensitivity is the main thing we care about in a screening test: we want the test to miss none of the patients who have the disease. A perfect screening test would have a sensitivity of 100%, meaning that if 100 people have colon cancer and have the test, all 100 people will get a “positive” test result, meaning no false negative tests.

Sensitivity isn’t everything however…we also want a test that gives a negative result when someone does not have the disease in question. That is, if you take a group of 100 people that do not have colorectal cancer, a perfectly specific test will have 100 “negative” results, meaning no false positive tests.

What does a positive Cologuard test mean?

First and foremost, a positive result on the Cologuard test means that you need to have a colonoscopy. Not a virtual colonoscopy, or another stool test, or another scan of some sort…you need a real optical colonoscopy. Luckily, only about 4% of people with a positive Cologuard test will have cancer found on colonoscopy. 51% will have a precancerous polyp. The rest (45%) will have nothing found on colonoscopy. So to simplify even further, just a little more than half of people with positive results will have something abnormal (cancer or a polyp) found on colonoscopy.

What does a negative Cologuard test mean?

A negative test means that there is a less than one-percent chance of having cancer found on colonoscopy. However, about 34% of people with negative tests still have precancerous polyps found on colonoscopy, with the remainder (66%) of people with negative Cologuard results having truly negative colonoscopies.

What is immediately apparent from these numbers is that Cologuard rarely misses cancer. However, if we count polyps as a significant finding, there are plenty of false-positive results (45%) and plenty of false-negatives too (34%).

A word on how health insurance companies view Cologuard

While not important to the medical reasoning behind choosing colonoscopy or Cologuard, for some people it is important to note the finances of each test. Either colonoscopy or Cologuard can be considered a screening test, and is typically covered by health insurance plans without an out-of-pocket cost. However, if a Cologuard test is positive (remember that 45% false positive rate discussed above), the insurance company now views the necessary colonoscopy as a diagnostic colonoscopy, not a screening colonoscopy. Diagnostic tests often have an out-of-pocket responsibility for the patient and in the case of a colonoscopy this can be in the thousands of dollars range. This is something rarely discussed when ordering a Cologuard test in the primary care setting, but that we often need to educate patients about when it’s time to book their colonoscopy to follow up a positive Cologuard test.

What about colonoscopy? Are there any downsides?

In good hands, colonoscopy is an excellent test—it’s the best test we have in the fight against colon cancer. However, no test is perfect and colonoscopy is no exception. Even though colonoscopy is the gold-standard test, here are some of the negative things to know about colonoscopy.

Colonoscopy requires a bowel preparation, meaning you have to take either a liquid prep or pill prep to clean out the colon the day before. It’s not painful, but prepping for a colonoscopy is far from a good time. Colonoscopy has small but real risks, such as bleeding, infection, perforation of the bowel, and anesthesia problems. However these risks are very rare, and in with a skilled team the risk of a serious complication is far less than 1 in 1,000 procedures. Colonoscopy also has a miss rate for polyps and even cancer. It is very hard to define an actual number of missed lesions because it’s difficult to perform a study on the gold-standard test (colonoscopy) as there is no better test to compare it to. That being said, colonoscopy can miss small polyps around 20% of the time, and can even miss cancer a few percent of the time. The devil is in the details however: Missing a significant lesion during an outpatient screening colonoscopy in a properly prepped patient (meaning the patient did the bowel cleanse effectively) with a doctor that performs high-quality colonoscopy (meaning the doctor spends adequate time and uses excellent technique to find and remove polyps) is quite a rare event and is something that is difficult to study given variations in quality practice between doctors even in the same community or hospital system.

Here is a quick pros and cons table to help clarify all of the above

Measure Colonoscopy Cologuard®
Prevention of colon cancer? Yes Not really
Repeat a normal test every 10 years 3 years
Overall convenience Bowel prep and 1 day off work No prep but have to handle stool
Overall invasiveness Moderately invasive Not invasive
Accuracy Very accurate Not very accurate
Biggest upside of the test Better cancer prevention and accuracy Easy and can do it at home
Biggest downside of the test Bowel prep and less than 0.1% chance of complications Lots of false positives that will require a colonoscopy anyway

How do I choose between colonoscopy and Cologuard in my practice?

I typically reserve Cologuard testing for patients that just need to know if they have cancer right now, and are not in good condition to undergo colonoscopy due to other major health issues. A patient that has not been screened recently who is approaching 80 years old, and who has one or more major cardiovascular or pulmonary issues is a good candidate for Cologuard testing. For pretty much everyone else, colonoscopy is by far the better test.


Imperiale TF, Ransohoff DF, Itzkowitz SH, et al. Multitarget stool DNA testing for colorectal-cancer screening. N Engl J Med 2014;370:1287-97.

Cologuard website:

Cologuard is a registered trademark of Exact Sciences Corporation.

Fatty liver disease and the FibroScan® test

FibroScan schematic

Fatty liver disease is very common and can lead to serious health problems if ignored. Here is how to calculate your risk of having complications from a fatty liver, and how to find out if you would benefit from FibroScan testing.

What is fatty liver?

Fatty liver is a very common condition in the US, with an estimated prevalence of 40% of the population. Also known as hepatic steatosis, this condition is characterized by the presence of excess fat storage in the liver. If the liver holds on to enough excess fat, it can become enlarged, inflamed, and lead to more severe liver problem in the future. Recently, fatty liver was renamed to steatotic liver disease (SLD) to avoid the stigma associated with the word “fatty” but this change in nomenclature will take many years to catch on and most people will continue to refer to this condition as fatty liver disease for the foreseeable future.

What causes fatty liver?

Most cases of fatty liver are related to a condition called nonalcoholic fatty liver disease (NAFLD) which was also recently renamed to metabolic dysfunction-associated steatotic liver disease (MASLD), but excess alcohol use is another common cause of fatty liver disease, as are many other liver conditions.

Who gets fatty liver?

Risk factors for developing fatty liver disease include diabetes, obesity, having other metabolic diseases such as high blood pressure, high cholesterol, or high triglycerides, or drinking excess alcohol (more than 2-3 drinks a day for men, or more than 1-2 drinks a day for women). Overall the metabolic dysfunction that leads to fatty liver is characterized by insulin resistance, low or dysfunctional muscle mass, and the inability to properly dispose of (meaning burn or store properly in liver or muscle) excess calories taken in from food sources.

Now let’s look at the main risk factors for fatty liver disease in more detail:

Diabetes: About 70% of patients with type 2 diabetes have fatty liver. Diabetics are the highest risk group of people to develop fatty liver.

Obesity: Living with obesity is a risk for fatty liver also. The easiest way to define obesity is to use the body mass index, or BMI, with a BMI greater than 30 defining obesity. Being overweight, meaning your BMI is between 25 and 30, is also a risk factor for fatty liver, especially if you have other metabolic risk factors.

Alcohol: Alcohol use is a major cause of fatty liver disease, as well as alcoholic hepatitis and cirrhosis. The type of drink doesn’t matter, as a standard serving of beer (12 oz), wine (5 oz), and liquor (1.5 oz) all contain the same amount and type of alcohol. What really matters is the amount of alcohol consumed weekly, and the time (months to years) that this consumption goes on for. To illustrate this point with some real numbers, men < 65 years old are at risk of alcoholic liver disease by drinking more than 14 drinks per week, or more than 4 drinks per occasion, and women or people >65 years old are at risk by drinking more than 7 drinks per week, or more than 3 drinks per occasion. If these numbers seem low, that should drive home the point that alcohol is a toxin to the liver and should be significantly limited or better yet completely eliminated from the diet. Some people are more susceptible to the damaging effects of alcohol than others: In fact, cirrhosis can occur in up to 30% of people who consume only 2-3 drinks per day for many years.

Are there symptoms of fatty liver disease?

Often thought of as an asymptomatic condition, fatty liver disease actually does have several associated symptoms:

Abdominal pain: Typical pain from fatty liver is mild, dull, nagging and located in the right upper abdomen. Sometimes the pain is felt in the right flank and/or in the back too. The pain can be worse with bending forward, and is sometimes more noticeable in the evenings.

Fatigue: Since it’s an inflammatory condition, fatty liver can cause a feeling of generalized fatigue.

Pruritis: This is the fancy term for itchy skin. It’s typically mild or nonexistent  in most people with fatty liver, but occasionally itchy skin becomes a problem with advanced fatty liver disease.

Metabolic dysfunction: While not technically a symptom, metabolic dysfunction is often the root cause behind the common complaints of the feeling of inability to lose weight, bloating, low energy, poor sleep, and so-called “brain fog” that often is associated with underlying insulin resistance and poor metabolic health. The onset of fatty liver is often one of the first measurable signs that something is very wrong.

Why is fatty liver dangerous?

By itself, having fatty liver alone increases your risk of several other non-liver related conditions, most notably heart disease, stroke, cancer, and also increases all-cause mortality (the risk of death in general). In non-diabetics, having fatty liver greatly increases the chance of developing diabetes in the future by contributing to a condition known as insulin resistance.

However, in some people with fatty liver disease, the liver cells become chronically inflamed. Blood tests may show elevated liver numbers (AST and ALT) because the damaged liver cells are leaking their enzymes into the blood. When liver inflammation from fatty liver occurs, it is called nonalcoholic steatohepatitis, also known as NASH (this condition was also renamed recently to metabolic-dysfunction associated steatohepatitis, or MASH).

Left alone for a few years, people with inflamed fatty livers can slowly develop scar tissue in the liver called fibrosis. This scarring is the body’s attempt to repair the chronic inflammation from the inflamed liver cells. However unlike inflammation from a wound or surgery which typically gets better as time passes, the inflammation from NASH is ongoing, causing the body to lay down scar tissue in the liver for years and years. The end result of this process of progressive fibrosis of the liver is cirrhosis, or end-stage scarring in the liver that causes permanent dysfunction of the liver.

How do I know if I have fatty liver or liver fibrosis?

Despite the above symptoms, most people with fatty liver disease or liver fibrosis are walking around living their lives without a clue that there is liver damage happening behind the scenes.

Occasional blood testing to measure the liver enzymes is a decent way to evaluate for fatty liver disease. However, many patients with fatty liver disease and even patients with advanced liver damage may have completely normal liver function tests. An abdominal ultrasound, CT scan, or MRI can often suggest fatty liver too. However none of these methods are very accurate in identifying patients with advanced fatty liver disease, and liver biopsy remains the gold standard test for diagnosis of fatty liver, liver fibrosis, and cirrhosis. However liver biopsy is invasive, sometimes painful, costly, and has significant risks like bleeding.

A more sophisticated test for fatty liver disease and liver fibrosis is called FibroScan. A FibroScan test is a type of ultrasound test that measures the physical properties of the liver to determine liver fat content and liver stiffness. FibroScan can be thought of as a non-invasive liver biopsy and it samples a larger area of liver tissue when compared with a traditional needle biopsy.

How does FibroScan work?

Fibroscan is painless, non-invasive, and takes about 5-10 minutes to perform. It is similar to a traditional ultrasound as it uses a small ultrasound probe to locate the liver, but instead of taking images of the liver, FibroScan is used to measure certain properties of the liver tissue instead.

FibroScan measures liver steatosis, meaning how much fat is contained in the liver. So instead of a traditional ultrasound or CT scan that just states (for example) mild fatty liver, or severe hepatic steatosis, FibroScan will produce a numerical value that corresponds to the amount of steatosis (fat) in the liver. This number is more accurate than just estimating the severity based on traditional imaging, and can be used to follow a patient’s progress as time goes on. When the steatosis number goes up, the fatty liver is becoming more severe. If the patient is successful in treating their fatty liver, we can watch the steatosis number improve which is proof that the disease is improving.

More importantly, FibroScan allows the measurement of liver fibrosis. This is the value that we truly care about, as fibrosis (liver scarring) is what ultimately correlates with all the bad outcomes of liver disease. If a patient is developing fibrosis, we need to take more drastic action to prevent the fibrosis from progressing into liver cirrhosis over the next few years. FibroScan measures fibrosis by calculating liver stiffness. To do this, the ultrasound probe will send a small pulsed vibration (it feels like a mild tap on the body) through the liver, and measure how fast the liver moves after this small vibration. The vibration wave will pass very quickly through a stiff liver, which means the liver tissue is fibrotic. The vibration wave will pass more slowly through healthy and pliable liver tissue, meaning no fibrosis is present.

Here is an analogy for how the FibroScan measures liver stiffness: Think of tapping your knuckle on a stiff surface like your kitchen table…the force travels rapidly across the table and if someone puts their ear to the other side of the table they would hear the tap almost instantly as it is transmitted through the table. Now try this same experiment on your couch cushion. This is a pliable (not stiff) surface, and the force of your tapping knuckles will be dissipated by the movement of the couch cushion and barely audible to a person with their ear on the couch. That’s how FibroScan works to measure liver stiffness and calculate liver fibrosis.

FibroScan being performed on patient

Who should get a FibroScan test?

There are several indications for FibroScan. Since fatty liver disease is severely underdiagnosed in the population (meaning many people are walking around with significant liver disease and don’t know about it), many of the major medical societies have recently changed their guidelines to push for early detection and treatment of fatty liver disease.

Before we get into the details, we need to review something called the FIB-4 score. This simple non-invasive scoring system was derived to help see who is at risk of more advanced liver disease (fibrosis). It requires only a few values available from routine blood tests: platelet count, AST, and ALT. You can calculate your FIB-4 score below.

  • If your FIB-4 score is low (less than 1.3), you have a low risk of liver fibrosis.
  • If your FIB-4 score is high (greater than or equal to 1.3), you are at higher risk of liver fibrosis and more testing is needed.

So who should check their FIB-4 score?

Patients who are obese: In patients with obesity (BMI>30), and the presence of two or more metabolic risk factors (high blood pressure, high triglycerides, low HDL cholesterol, prediabetes), the FIB-4 score should be used to determine who needs further testing with FibroScan.

Patients with type 2 diabetes: All type 2 diabetics should be screened using the FIB-4 score, even without having other risk factors like obesity or metabolic syndrome.

If you are in one of the two groups above, and your FIB-4 score is greater than or equal to 1.3, you should get a FibroScan for further assessment of your liver.

Who else should get FibroScan testing?

Patients with elevated liver function tests (LFTs): If your liver tests are significantly elevated, you should have a complete evaluation to determine why this is the case. This typically involves further blood testing, ultrasound imaging, and often a FibroScan.

Patients with abnormal liver imaging: If you already have signs of fatty liver, fibrosis, or other signs of liver disease on imaging, you should consider FibroScan testing to better clarify your risk of developing more advanced liver disease.

Patients who consume a significant amount of alcohol: If you are worried about your drinking, or consume more than 21 drinks per week for a man, or 14 drinks per week for a woman, you should consider FibroScan testing to determine if you have fatty liver disease, fibrosis, or cirrhosis.


Fatty liver disease is very common and is a major risk factor for developing more severe liver diseases like fibrosis and cirrhosis. Most patients with diabetes, and many patients with obesity and other associated metabolic health problems have fatty liver disease. Alcohol is also a strong risk factor for developing liver disease. You can check the two most important measures of your liver health (steatosis and fibrosis) with a quick non-invasive FibroScan test.

Precision Digestive Care is the first practice in the Huntington area to offer FibroScan testing. This test is covered by most insurance plans. If you are in need of a FibroScan test, please contact us to schedule.

VIDEO: Colonoscopy prep with pills only! All about Sutab!

Doctor holding Sutab pill

The colonoscopy prep experience is by far the worst part of the whole procedure. For years, patients have been asking “Isn’t there a better way to do the prep?”

Well, now there is! There is a prescription bowel prep called Sutab that I have been using for the past two years for most of my colonoscopy patients. Sutab comes in a kit which includes 24 pills and a container to measure the water, and it couldn’t be any easier to take. Most of my patients that have used the older liquid preps in the past are pleasantly surprised after using Sutab for the first time!

Here is a short video I made showing you how to use Sutab. I also cover the diet you should follow to make sure your “clean out” is as clean as possible, and how to handle the common side effect of all bowel preps…nausea.

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.

VIDEO: See how a gastroenterologist does the colonoscopy prep!

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!

Get Dr. Gandolfo’s free ebook today!

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:

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

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!

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