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Learn About the Digestive Tract 

Your digestive tract, which may also be called the “gastrointestinal tract” or “GI tract,” is the route your food follows once you put it in your mouth.

The GI tract is where the food you eat is turned into the energy your body needs to do the things you want to do. It starts with your mouth, teeth and tongue.

Once you swallow, the food goes down your esophagus and into the stomach where it is turned into mush. From your stomach, the food mush moves into the small intestine where the pancreas and liver help digest the food further so your body can use the energy.

The last part of the GI tract is the large intestine, rectum and anus — this is where the unusable bits of food you ate move out of your body.

We give you a more detailed tour of this route below (in Beyond the Basics).

Myth Busters 

  • “Not taking enzymes is a good way to treat constipation, because your stools get looser when you don’t take enzymes.”

    NOT TRUE! Not taking your enzymes puts you at INCREASED RISK of having constipation or a bowel obstruction. If you are getting constipated or straining to move your bowels, keep taking your enzymes but add fiber to your diet and get some medicine to keep your stools loose and bulky.

  • “I have bowel movements every day, so I can’t be constipated.” 

    NOT TRUE! People with CF who are constipated almost always have bowel movements every day, often more than once a day.

  • “My doctor told me I have a working pancreas (pancreatic sufficient) so I have a normal GI tract.”

    NOT TRUE! You may still be prone to constipation and you should eat a high-fiber diet. You may need medication on occasion. Also, your pancreas is still sensitive to injury, so binge drinking of alcohol can change you from someone with a working pancreas to someone whose pancreas doesn’t work right.

Beyond the Basics: A Tour of Your Digestive Tract 

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Basics of the Pancreas

The pancreas is an organ that lies behind your stomach, is shaped like a small fish, and is crucial for proper digestion.

The normal pancreas:

•  Makes special chemicals called "pancreatic enzymes" to digest food as it moves from the stomach into the intestines.
•  Makes the body's natural antacid called bicarbonate to mix with food coming from your stomach into the intestines.
•  Squirts fluid into the intestines to help flush food along its path through the digestive tract.
•  Makes important hormones, including insulin.

About 90 percent of people with CF have a pancreas that doesn't make enough enzymes to digest food. Undigested food in your intestines can cause pain.

Everyone with CF (including people who don't need enzymes) has a pancreas that does not make enough bicarbonate to neutralize stomach acid. This can contribute to pain.

Once you chew and swallow, your food goes down the esophagus and into the stomach. The stomach makes acid, which helps break down the food. Next, the food moves into the small intestine where the body starts taking the nutrients and vitamins out of the food.


To extract these nutrients, the body needs the help of the pancreas, an organ attached to the small intestine by a tube. The pancreas makes fluid — actually, a lot of fluid — that mixes with the food.

One part of that fluid is a product that neutralizes the acid from the stomach. It is called “bicarbonate.” Also in that fluid are chemicals called “pancreatic enzymes” that mix with the carbohydrates, proteins and fats in the food to break them into small bits the body can take in.

Pancreatic enzymes are very important in getting the nutrients, calories and vitamins into our bodies; they are the heart of good nutrition and health.

In addition to playing these important roles in the digestive process, the pancreas also is a maker of important hormones, including insulin. Insulin works in your blood stream, not in your intestines. Insulin helps move the sugar and fuel from the blood into the cells so they can do their work.

For many people with CF, the pancreas doesn’t produce enough insulin or the body doesn’t let insulin do its job, leading to CF-related diabetes (CFRD).

One way to simplify this is to think of the pancreas as two separate organs — one is a digestive organ that makes pancreatic enzymes for the intestines, the other is a hormone organ that makes insulin for the body. 


The next organ on our tour is the liver, which, among its many functions, makes a fluid called “bile” that helps the body absorb fat. Bile travels through small tubes in the liver and is stored in the gallbladder, which can empty the bile into the small intestine.

For some people with CF, bile gets thick and flows very slowly. It can even get so thick that it forms stones in the gallbladder, which is sometimes removed. You can still have normal digestion if your gallbladder has been removed.

As the mixture of food, pancreatic fluid, bile and pancreatic enzymes is moved along the small intestine, the important nutrients make their way into the body through the walls of the intestines.

Large Intestines

After the small intestine comes the large intestine. A few nutrients are taken in by the large intestine, but its more important function is to keep the balance of fluid just right in the mass of what remains of the digested food.

The very end of the large intestine is called the “rectum.” This is where the mass of fully digested food leaves your body in the form of "poop," or bowel movement. (There are a lot of other names for poop, but we will not go over them here!) As you probably know by now, your care team will usually ask you about your bowel movements.

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Updated 07/20/12