What Causes Steatorrhea (Fatty Stool)?

Noticing oily, pale, or hard-to-flush stools? It could be more than just something you ate. Fat in your stool, known as steatorrhea, can signal trouble with how your body digests or absorbs fat. While it’s sometimes caused by diet, frequent episodes may point to issues with your pancreas, liver, or intestines. Understanding what fatty stool means can help you know when it’s time to seek medical advice.

What Does Fat In My Stool Mean?

Steatorrhea is the medical term for too much fat in your stool (poop). Steatorrhea is not a medical condition. Instead, it can be a symptom of many health conditions.

You may have an occasional fatty stool after eating too much dietary fat. But if you have repeated bouts of steatorrhea, it is a sign that something isn’t working properly in your digestive tract.

This can occur when the small intestine and its supporting organs, such as the pancreas and liver, have problems digesting or absorbing fats from food, resulting in excess fat being excreted in the stool.

The following changes in your stools may indicate steatorrhea:

Bulky stools
Pale color
Foul smell
Possible floating and difficult to flush

You may also notice oil separation or oily droplets in the toilet water.

Common Causes of Steatorrhea

Steatorrhea can be a symptom of many health conditions, indicating the complexity of the digestive system.

In healthy people, the digestion of fats occurs in the small intestine with the help of digestive enzymes such as pancreatic lipases and bile from the liver.

Decreased fat absorption, leading to fatty stools, can occur due to a problem with any of these organs.

Below are some of the health conditions that may present steatorrhea as a symptom.

High Fat and High Fiber Diet

Occasional steatorrhea is not a concern and can occur due to a diet high in fat, fiber, or potassium oxalate.

Examples of foods high in fat or containing difficult-to-digest fats and fibers include whole nuts, oily fish, spinach, fatty foods, red meat, coconut oil, palm oil, mineral oil, castor oil, butter, shortening, lard, whole wheat products, processed coffee creamers, and alcohol.

However, this is not an exhaustive list, and other high-fat or high-fiber foods can also cause occasional steatorrhea.

Maintaining a food diary can be a practical way to track the types of food that may cause digestive symptoms.

Exocrine Pancreatic Insufficiency

Pancreatic exocrine insufficiency refers to any pancreatic disease that prevents the pancreas from producing enough digestive enzymes.

Examples of such conditions include:

Gallstone pancreatitis
Chronic pancreatitis
Pancreatic cancer
Alcohol use disorder
Zollinger-Ellison syndrome (excess gastric acid)
Cystic fibrosis

Obstruction of the pancreatic duct can hinder the flow of pancreatic enzymes to the small intestine.

This blockage can prevent the small intestine from receiving the necessary digestive enzymes, resulting in an inability to properly break down and absorb fats.

Liver and Biliary Tract Diseases

Conditions that prevent the liver from making bile acid or the bile ducts from delivering bile to the small intestine can lead to steatorrhea. Examples of such conditions include cholestasis, primary sclerosing cholangitis, primary biliary cholangitis, cirrhosis, and liver failure.

Malabsorption Syndromes

Conditions that prevent the small intestine from performing its functions, such as fat breakdown or fat absorption, can lead to excessive fat in the stool.

Examples include celiac disease (or coeliac disease with UK spelling), small intestinal bacterial overgrowth (SIBO), Whipple’s disease, Crohn’s disease, short gut syndrome, amyloidosis, lymphoma, and giardiasis.

Endocrine Conditions

Neuroendocrine tumors, such as gastrinomas, which release the hormone gastrin, can cause stomach ulcers, diarrhea, and oily stools.

Which Drug Causes Steatorrhea?

The weight loss drug orlistat (Xenical, Alli) can cause steatorrhea, or fat in the stool.

Recognizing Symptoms

Steatorrhea can be challenging to recognize in the early stages. However, the stools typically appear:

Bulky
Greasy or oily poop
Loose
Smelly
Foaming
Light colored
Floating
Visible fat globules
Difficult to flush

Symptoms of fat malabsorption can include chronic diarrhea, abdominal pain or discomfort, bloating, and weight loss.

Nutritional Impacts

In severe cases, steatorrhea can lead to growth failure and delayed puberty in children.

It can also cause visible loss of subcutaneous fat and muscle wasting.

Additionally, people with steatorrhea are at risk of developing deficiencies in fat-soluble vitamins, including vitamin A, D, E, and K.

When to Seek Medical Attention

Seek medical attention if you notice repeated bouts of fatty stools that are bulky, foul-smelling, greasy, loose, and light or clay-colored. Fatty stools tend to float in the toilet bowl and are difficult to flush. Your steatorrhea symptoms may be due to worsening of a known medical problem, or they may be the first sign of a previously undiagnosed condition.

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Diagnosis of Steatorrhea

Medical History and Physical Examination

Your doctor will start by obtaining a detailed medical history and performing a physical exam to find out if you have steatorrhea and gather clues about the underlying cause.

Stool Sample Analysis

Your doctor may ask you to submit a single stool sample for laboratory evaluation to identify fat globules. This is a qualitative test for steatorrhea.

In addition, your healthcare provider may ask you to collect stool samples for a fecal fat analysis test, a quantitative test that measures the fat content in a 24- to 72-hour stool sample.

The result tells your doctor how much of the fat in your diet is getting absorbed in the small intestine and how much is being excreted from the body in stool.

Results of a quantitative fecal fat test are reported in grams per 24 hours (g/24 h).

In adults, normal levels are 2-7 grams per 24 hours, with fat making up less than 20% of the solid stool.

In babies, a normal result is less than 1 gram per 24 hours, with fat making up 30-50% in bottle-fed babies and 10-40% in breastfed babies.

Other Diagnostic Tests

To rule out a differential diagnosis and determine which digestive organ is causing steatorrhea, your healthcare professional may order a D-xylose test.

This test involves drinking a solution of a sugar called D-xylose and then providing a urine sample, sometimes also a blood sample.

If D-xylose is found in your urine, it means your small intestine is absorbing fats properly.

Your doctor will then look for problems in your pancreas, liver, or biliary system. If D-xylose is absent, it points to an intestinal problem.

Steatorrhea Treatment and Management

Treatment of steatorrhea depends on the underlying cause. In some patients, fatty stools can be alleviated by treating the underlying condition that causes the symptom.

Dietary Changes

If a high-fat diet is causing steatorrhea, your doctor may recommend avoiding specific foods, such as:

Whole nuts
Oily fish
Fatty foods
Red meat
Certain types of oil

If you have fat malabsorption, your doctor may recommend eating more healthy fats, such as:

Avocados
Olive oil
Nut butters
Oily fish (like mackerel, tuna, and salmon)

Medications

If the cause of your steatorrhea is exocrine pancreatic insufficiency, your doctor may prescribe pancreatic enzyme replacement therapy. If enough bile is not reaching your small intestine, they may prescribe a medicine called ursodeoxycholic acid (Ursodiol).

Dietary Supplements

In addition to treating the underlying cause of steatorrhea, you may need treatment for the complications of steatorrhea. For example, dietary supplements are used to treat deficiencies of fat-soluble vitamins. Food sources of fat-soluble vitamins include:

Vitamin A: Fish oil, butter
Vitamin D: Mushrooms, fatty fish
Vitamin E: Almonds, sunflower seeds, sunflower oil
Vitamin K: Green leafy vegetables like spinach and kale