Undigested Food in Stool: Should I Be Worried?

Medically reviewed by Michele Cho-Dorado, MD on November 2, 2017Written by Rachel Nall, RN, BSN, CCRN on November 2, 2017

 

The body eliminates wastes — mainly digested food materials — through your stool. However, sometimes you may notice that some foods appear intact and unchanged in your stool.

While this isn’t usually a cause for concern, there may be some circumstances when a person with undigested food in their stool should see their doctor.

What causes undigested food in stool?

The most common cause of undigested food in stool is fibrous food. While the body can break down most foods, fiber remains largely undigested. However, eating fiber can be beneficial, because it adds bulk to the stool.

Stool that’s bulkier stimulates the walls of the intestines to move. This helps propel food material forward for digestion. Examples of high-fiber food particles that often remain largely undigested include:

  • beans
  • corn
  • grains, such as quinoa
  • peas
  • seeds, like sunflower seeds, flax seeds, or sesame seeds
  • skins of vegetables, such as bell peppers or tomatoes

Corn is an especially common culprit for undigested food in stool. This is because corn has an outer shell of a compound called cellulose. Your body doesn’t contain enzymes that specifically break down cellulose. However, your body can break down the food components that are inside corn.

If you see what appears to be whole corn kernels in your stool, chances are you’re only seeing the outer shell of the corn.

Should I be concerned?

Seeing these particles in your stool isn’t usually a cause for concern. Some people may be worried they aren’t getting enough nutrients in the diet, though. However, the body is not meant to break down all fiber forms.

Eating slower and chewing food more carefully can make less food particles appear in your stool. Food that’s chewed more thoroughly and in smaller pieces makes it easier for your digestive enzymes to break down the food.

Another option is to steam foods, especially vegetables. By making the foods softer, they’re easier for the body to break down and maximize nutrient absorption.

Typically, it takes about one to three days for food material to pass through your digestive tract and exit via your stool. If you notice the food particles in your stool much sooner, this could indicate that stool is passing more quickly than usual.

Stool should be easy to pass. It shouldn’t feel hard or dry. While the appearance of stool can vary from person to person, the general appearance of stool should be soft and brown in color.

When to see your doctor

While undigested food in stool isn’t something to worry about for the most part, there are some exceptions. The presence of undigested food could indicate food is passing too quickly through the digestive tract and not being properly digested. See your doctor if you experience any of these symptoms:

  • changes in bowel habits, such as loss of bowel control
  • persistent diarrhea
  • unexplained weight loss
  • blood in the stool

These symptoms could indicate an underlying condition. Some conditions include:

  • Celiac disease. The body can’t properly break down gluten, a protein found in many foods, especially bread products.
  • Crohn’s disease. This is a form of inflammatory bowel disease, where a person experiences significant inflammation in their digestive tract.
  • Pancreatic insufficiency. The pancreas may not be making enough enzymes to properly break down food particles.
  • Irritable bowel syndrome (IBS). This condition may be caused by an overly sensitive colon.
  • Lactose intolerance. In this condition, your body doesn’t have enough of the lactase enzyme to digest lactose, a carbohydrate lactose.

These are just a few examples of conditions associated with the presence of undigested food.

Next steps

If a doctor is concerned about the presence of undigested food in the stool as well as other symptoms, they may order a stool test. This test involves collecting a sample of stool and sending it to a laboratory for evaluation. The test may look for the presence of blood, fat, or undigested food materials.

Sometimes a doctor may order blood testing to test for low blood counts due to gastrointestinal bleeding or the presence of nutritional deficiencies. If a person is especially nutritionally deficient, this could indicate the presence of a food allergy or intolerance.

The bottom line

In the absence of other digestive-related symptoms, undigested food particles in the stool is usually not a cause for concern. Talk to your doctor if you develop symptoms that concern you.

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