Gas, Bloating and Colon Cancer

Deciphering Gastrointestinal Distress Signals

Man with stomachache
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Bloating after a Thanksgiving day feast or passing gas following a loaded bean burrito is probably normal, but gas and bloating also are symptoms of colon cancer. Therefore, pay attention to your gastrointestinal distress signals – this is how your body notifies you that something is amiss in your digestive tract and colon.

What Is Gas and Bloating?

In case you are counting, it is normal to pass gas up to 23 times per day.

Gas production is a normal byproduct of digestion. Excessive gas and bloating can either be a symptom of a gastrointestinal problem or a normal occurrence as food or drink moves through your digestive system. These symptoms are usually paired together – the released gases make you feel bloated or uncomfortable. The gas is the problem; the bloating is an outward symptom of the problem.

Gas is composed of odorless vapors such as nitrogen and oxygen. The good bacteria in your large intestine is responsible for the sulfurous odor – they release sulfur-containing gases during the final digestion of your food.

Treat the Cause, Then the Symptom

Gas and bloating have many causes aside from colon cancer. These symptoms can be a normal byproduct of the food you eat or a gastrointestinal SOS signal that you ingested bad foods. Consider many of the digestive disorders that list gas and bloating as a symptom:

Trigger Foods

Certain foods and drinks can trigger gas (and foul odors):

  • Onions
  • Soy products (tofu, soy milk)
  • Sprouts (alfalfa, mung, brussels)
  • Whole grains
  • Cucumbers
  • Dairy products (cheese, milk, butter)
  • Processed foods
  • Soluble and insoluble fibers
  • Cruciferous vegetables (cauliflower, broccoli)

Some of these foods can also add to the foul odor of your gas including asparagus, eggs, garlic and onions, fish and cruciferous vegetables.

Decreasing Your Gas

You can start a food diary to see if any of these foods (or others) are causing gas. Make a column for the foods you eat and another for any symptoms you have following the meal. Watch for trends of discomfort after certain foods, such as dairy, and report your findings to your doctor.

Alongside the foods that you digest, gas and bloating can be triggered through mechanical digestive problems (chewing, swallowing). The most common mechanical causes of gas and bloating include:

  • Smoking
  • Chewing gum
  • Eating too fast
  • Poor-fitting dentures
  • Drinking through a straw
  • Swallowing air

What goes in must come out – either through your upper digestive tract (burping) or through the lower (passing gas). The more air that you ingest, either through gas-causing foods, drinks or mechanically, the more air you will have to pass to decrease painful bloating.

Gas and Colon Cancer

As a sign of colon cancer, gas and bloating are late symptoms. An obstruction caused by a tumor could lead to bloating and the trapping of gas within the colon. If you have a family history of colon cancer, genetic polyp disorders or are concerned about your risk of colon cancer, talk to your doctor about scheduling a colon cancer screening exam.


If you are frequently having gas, bloating and discomfort (not a one-time deal after a big meal) your doctor may order some tests to find the cause. Your doctor may order:

  • X-rays of the abdomen
  • Upper gastrointestinal series (upper GI)

These tests, along with your personal and family medical history, will help the doctor find any digestive disorders (including cancer) that could be causing excessive gas and bloating.

Gas After Colon Surgery

If you have been treated for colon cancer with a bowel resection (colectomy) and received a colostomy, your doctor will put you on a low-residue diet for weeks following your operation. This diet involves eating foods that easily digestible and will not cause you excess discomfort with gas and bloating. Pay special attention to your bowel habits with a colostomy, as constipation or improper irrigation techniques could also lead to irritation of the colon and excessive gas.


National Digestive Disease Information Clearinghouse. (n.d.). What I Need to Know About Gas. 

Ohio State University Medical Center. (n.d.). Gas in the Digestive Tract