Last Review Date: December 30, 2018
Malabsorption is a condition caused by the decreased ability to digest and/or absorb nutrients from food. It is seen with a variety of diseases and can lead to general malnutrition or to symptoms associated with deficiencies in specific nutrients.
The body requires a steady supply of nutrients to build, repair, and maintain itself, to produce energy, , , , cells, tissues and bone, and to fight infections. Nutrients come from the diet and include fats, proteins and carbohydrates (macronutrients) and many essential vitamins and minerals (micronutrients).
Food that is eaten is digested in three stages:
- Proteins, fats, and complex sugars (carbohydrates) are broken down by stomach acids, enzymes produced by the pancreas, and from the liver. This process also releases micronutrients.
- Nutrients are absorbed primarily by cells in the small intestines.
- Nutrients are transported throughout the body and used or stored.
Any disruption or interference with this process can lead to malabsorption. The type and severity of deficiencies seen and the symptoms experienced depend on whether the problem affects general digestion and absorption or affects one or more specific nutrient.
Fat, proteins and carbohydrates cannot be properly digested without bile and pancreatic enzymes. Insufficiencies in these substances can occur, for example, with liver and pancreatic diseases that limit their production, and with conditions such as cystic fibrosis that prevent pancreatic enzymes from getting to the digestive tract.
If the intestines are unable to or prevented from absorbing nutrients, then the nutrients are eliminated from the body in the stool. This can happen when there is damage to the intestinal cells and tissues or when the intestines have been shortened, such as due to surgery, reducing the surface area and the amount of time available in which nutrients can be absorbed from food as it passes through the digestive tract.
As an example of a specific deficiency, vitamin B12 absorption requires both stomach acid and intrinsic factor, a substance produced by in the stomach. Stomach acid separates B12 from proteins and intrinsic factor binds with B12. A lack of either one prevents intestinal absorption and can lead to vitamin B12 deficiency. This can happen with advancing age, with medications that suppress stomach acid production, with gastric bypass surgeries, and with diseases that damage parietal cells or cause general malabsorption.
Once absorbed in the intestines, nutrients may be hindered from being transported throughout the body. This may be caused by problems with the such as lymphoma or the rare inherited disorder, abetalipoproteinaemia.
Within these categories, there are a number of conditions and diseases that can cause malabsorption and the associated and . Below is a list of just some of these:
- Narrowing, closure or absence of bile ducts (biliary atresia) or blockage of bile flow (cholestasis) causing a lack of bile for digestion
- Cancers, including pancreatic cancer, lymphoma, stomach cancer
- Coeliac disease—an autoimmune disease that causes damage to the lining of the intestines (intestinal villi)
- Cystic fibrosis—a genetic condition that affects the pancreas and the transportation of pancreatic enzymes to the site of digestion
- Damage to the intestines, such as from radiation treatment
- Decreased intrinsic factor production
- Diseases that affect circulation, such as congestive heart failure
- Food intolerances and enzyme deficiencies
- HIV and AIDS
- Inflammatory bowel disease (Crohn disease and ulcerative colitis)
- Liver diseases
- Medications, such as phenytoin and those that inhibit stomach acid production
- Pancreatic diseases and pancreatic insufficiency—can cause decreased amounts of pancreatic enzymes
- infections of the digestive tract, such as Giardia lamblia or a tapeworm
- Surgery, such as a bowel resection or gastric bypass
- —a rare condition causing tumours in the pancreas and/or intestines
The and of malabsorption depend upon the underlying cause as well as the type and severity of nutrient deficiencies. They may become evident quickly or develop slowly and worsen over time. Some nutrients, such as vitamin B12, are stored by the body and symptoms only emerge when stores become depleted. Symptoms associated with insufficient pancreatic enzymes may not emerge until about 90% of the body's production capacity is disrupted.
Some of the most common signs and symptoms seen with general malabsorption include:
- Persistent diarrhoea.
- Fatty stools that are loose and foul-smelling (steatorrhoea).
- Failure to thrive in children.
- Abdominal pain, cramps, bloating, and gas.
Other signs and symptoms may be due to general ill health or to specific deficiencies caused by malabsorption. They may include:
- Weakness, fatigue.
- Fluid build-up in the abdomen ().
- Dry and scaly skin, rash.
- Inflammation of tongue (glossitis).
- Muscle wasting, unexplained weight loss.
- Nausea and vomiting.
- Swelling of the hands, feet and legs (peripheral ).
- Inflammation of mouth (stomatitis).
- Easy bruising, bleeding gums.
- Numbness and tingling in feet and hands.
- Muscle or bone pain.
The following are some complications that can develop over time as a result of chronic malabsorption:
The purpose of testing may be to:
- Screen those at risk for malabsorption because of an underlying condition such as cystic fibrosis.
- Detect malabsorption, identify its underlying cause(s), and evaluate the types and severity of nutrient deficiencies present.
- Detect complications such as anaemia.
- Monitor the effectiveness of treatment in people with malabsorption.
There is no single test that can identify malabsorption or the underlying cause. Typically, a doctor will take into account many factors when ordering tests, including results from a physical examination, family history, medical history, and and . Testing will often be performed in steps with results leading toward a diagnosis while ruling out other possible causes. Testing typically involves ordering:
- An initial set of general tests that evaluate body organs, cells, and digestion and that look for a cause for a person's persistent diarrhoea, one of the most common symptoms of malabsorption.
- Specific follow-up tests that are used to detect or exclude diseases associated with malabsorption and to identify specific deficiencies and/or complications.
Initial testing may include:
Based upon initial testing results, the person's symptoms, and the doctor's suspicions, follow-up testing may include one or more of the following:
Tests sometimes ordered include:
- Methylmalonic Acid (MMA) – to detect early vitamin B12 deficiency.
- Hydrogen breath test – to detect lactose intolerance and bacterial overgrowth in the digestive system (carbohydrate malabsorption).
- Lactose absorption test – though this test is primarily used to detect a deficiency in the lactase (lactose intolerance), it may sometimes be used to identify malabsorption.
- of the intestine (through an endoscopy).
Testing to examine the digestive tract, liver, and/or pancreas is sometimes necessary and may include:
- Abdominal .
- Endoscopic retrograde pancreatography (ERCP).
Learn more about imaging procedures at our feature article Other Testing: Radiology
A person affected by malabsorption can work with their doctor, a nutritionist, or other health care professionals to address and manage their condition. Treatment of malabsorption typically includes one or more of the following:
- Addressing the underlying cause to the extent possible to minimise malabsorption symptoms and intestinal damage.
- Replacing missing nutrients; this may include the use of oral pancreatic enzyme supplements and the replacement of minerals and vitamins A, D, E, and K, vitamin B12 and folate, etc.
- Making nutrient-rich foods available; for some people, a low-fat, high-protein diet may be recommended; for others, significant diet alterations, such as a gluten-free diet, may be necessary.
- Working with the doctor to develop a treatment plan that is tailored to an individual person's clinical situation.
- Monitoring the person's health status over time; this often involves performing laboratory tests such as a FBC or E/LFTs at regular intervals.
On This Site
Tests: FBC, E/LFTs, Faecal Occult Blood, Vitamin B12 and Folate, Coeliac Disease Tests, O&P, Vitamin D, PT, Sweat Choride, Faecal Elastase,Trypsin
Conditions: Malnutrition, Coeliac Disease, Vitamin B12 Deficiency, Cystic Fibrosis, Pancreatic Insufficiency
Elsewhere On The Web
Healthdirect Australia - malabsorption
Better Health Channel: Digestive System
MSD Manual: Overview of Malabsorption (USA)
American Academy of Pediatrics, Healthy Children: Malabsorption (USA)
National Digestive Diseases Information Clearinghouse (NDDIC): Your Digestive System and How It Works (USA)