What is malabsorption syndrome?

Key points

  1. Malabsorption syndrome occurs when something prevents the bowel from absorbing important nutrients and fluids, including proteins, fats, and vitamins.
  2. Malabsorption can be caused by conditions such as celiac disease, Crohn’s disease, lactose intolerance, and intestinal damage.
  3. Risk factors include a family history of malabsorption or cystic fibrosis, excessive alcohol consumption, and travel to the Caribbean or Southeast Asia.

Malabsorption syndrome refers to a number of disorders in which the intestine can’t adequately absorb certain nutrients into the bloodstream. It can impede the absorption of macronutrients (proteins, carbohydrates, and fats), micronutrients (vitamins and minerals), or both.

Causes of malabsorption syndrome

Proteins, carbohydrates, fats, and most fluids are absorbed in the small intestine. Malabsorption syndrome occurs when something prevents the bowel from absorbing important nutrients and fluids. The problem may be caused by inflammation, an injury to the lining of the intestine, or an intrinsic disease, one that originates within the body. Sometimes the condition may be the result of the body’s failure to produce enzymes needed to digest certain foods or to adequately mix the food with the enzymes and acid produced by the stomach. 

Factors that may affect the digestion of food and cause malabsorption syndrome include:

  • prolonged antibiotic use
  • other conditions such as celiac disease, Crohn’s disease, chronic pancreatitis, or cystic fibrosis
  • lactase deficiency, or lactose intolerance, which is fairly common in people of African or Asian descent and happens when the body lacks the enzyme needed to digest lactose, a sugar present in milk 
  • congenital, or birth defects, such as biliary atresia, which is when the bile ducts don’t develop normally and may become blocked and prevent the flow of bile from the liver
  • diseases of the gallbladder, liver, or pancreas
  • damage to the intestine from infection, inflammation, trauma, or surgery
  • parasitic diseases
  • radiation therapy, which may injure the mucosal lining of the bowel

There are some fairly uncommon disorders that result in malabsorption. One possibility is short bowel syndrome. This condition may be a birth defect or the result of surgery. The surface area of the bowel decreases, and this hinders the bowel’s ability to absorb nutrients.

Another disorder that may lead to malabsorption is tropical sprue. This condition is most common in the Caribbean, India, and other parts of Southeast Asia. Its symptoms may include anemia, diarrhea, sore tongue, and weight loss. The condition may be related to environmental factors, such as toxins in food, infection, or parasites.

Learn more: Tropical sprue »

An even rarer possibility is Whipple disease, which usually affects middle-aged men. The condition is caused by a bacterial infection. A key symptom is often abdominal pain or cramps. Additional symptoms include:

  • chronic fever
  • darkening of skin pigment
  • diarrhea
  • joint pain
  • weight loss

Recognizing the signs and symptoms of malabsorption syndrome

Symptoms of malabsorption syndrome are caused by the passage of unabsorbed nutrients through the digestive tract. They will be different depending on the specific nutrient or nutrients that are not properly absorbed. Other symptoms are caused by a deficiency of that nutrient in the body:

  • If you are unable to absorb fats, you may have light-colored, foul-smelling stools that are soft and bulky. Stools are difficult to flush and may float or stick to the sides of the toilet bowl.
  • If you are unable to absorb protein, you may experience dry hair, hair loss, or fluid retention. Fluid retention is also known as edema.
  • If you are unable to absorb certain sugars, you may have bloating, flatulence, or explosive diarrhea.
  • If you are unable to absorb certain vitamins, you may have anemia, malnutrition, low blood pressure, weight loss, and muscle wasting.

Children with malabsorption syndrome may purposefully avoid certain foods. They may also fail to grow properly. Their weight or rate of weight gain may be significantly below that of other children of a similar age and gender.

Risk factors

Risk factors for malabsorption include:

  • excessive alcohol consumption
  • a family history of cystic fibrosis or malabsorption
  • intestinal surgery
  • use of certain medications, including laxatives or mineral oil
  • travel to the Caribbean, India, and other parts of Southeast Asia

Diagnosing malabsorption syndrome

A doctor may suspect malabsorption syndrome if the patient suffers chronic diarrhea, nutrient deficiencies, or has significant weight loss despite eating a healthy diet. Laboratory tests are used to confirm the diagnosis. These tests may include:

Stool tests

Stool tests can measure fat in stool samples. These tests are the most reliable because fat in the stool is usually present in this disorder.

Blood tests

These tests measure the level of specific nutrients such as vitamin B-12, vitamin D, folate, iron, calcium, carotene, phosphorus, albumin, and protein in your blood. A deficiency in one of these vitamins may not necessarily mean that you have malabsorption syndrome. It can mean that you are not choosing foods with healthy levels of nutrients. Normal levels of these nutrients suggest that malabsorption is not the problem. 

Breath tests

Breath tests can be used to test for lactose intolerance. If lactose is not being absorbed, it enters the colon. Bacteria in the colon will break down the lactose and produce hydrogen gas. The excess hydrogen is absorbed from your intestine, into your bloodstream, and then into your lungs. You will then exhale the gas. The presence of hydrogen gas in the breath after ingesting a product containing lactose means that you may have intolerance to lactose.


A biopsy is used if an abnormality in the bowel lining is suspected.

Treatment options for malabsorption syndrome

Nutrient and fluid replacement are the first steps in treating malabsorption syndrome. Specific treatment will depend on the cause. For example, if you are found to have lactose intolerance, you should avoid milk and other dairy products or take a lactase enzyme tablet. Hospitalization may be required in the most extreme cases.

If you have been diagnosed with malabsorption syndrome, you should consult with a dietician to make sure you are getting proper nutrients. You may need to take enzyme supplements that will help your body absorb the things it can’t on its own. You diet will be adjusted for the things you need and for the nutrients you cannot absorb. You will be monitored for signs of dehydration, which may include dizziness or weakness, increased thirst, low urine output, and dry mouth, skin, or tongue.


You asked, we answered

  • What are the long-term complications of malabsorption syndrome?
  • Complications are directly related to the type of nutrient not being absorbed. In some cases, people get persistent diarrhea, weight loss, and abdominal pain. Vitamin deficiencies can cause conditions like anemia, numbness in the hands or feet, and memory problems. Finding the cause is the key to proper treatment. The body needs to receive the proper nutrients in the proper proportions in order for it to function correctly. Missing vital nutrients can affect every system in the body including the heart, brain, muscles, blood, kidney, and skin. Children and the elderly are especially sensitive to these problems.

    - Judith Marcin