Nutritional Deficiencies

When a healthy individual eats, most of the food is broken down in the stomach and absorbed in the small in intestine. However, in many patients with Crohn's disease—and nearly all of those with small bowel Crohn's—the small intestine's ability to absorb nutrients is compromised, resulting in what is known as malabsorption.

Malabsorption can contribute to a number of health problems—including dehydration and malnutrition— which are serious and can be life-threatening.

Fortunately, blood tests can determine whether or not a patient is getting the vitamins and nutrients he needs. If he or she's not, a gastroenterologist can recommend a healthy treatment plan.

Causes of Malabsorption

A number of factors related to Crohn's disease may contribute to malabsorption.

First, chronic inflammation in those with small bowel Crohn's often leads to damage of the intestinal lining, interfering with the organ's ability to absorb nutrients.

Also, certain medications used to treat the disease, such as long-term corticosteroids, may also affect the body's ability to absorb protein.

Finally, a person who has had a portion of her small bowel surgically removed may simply have less of the intestine left to absorb food. This condition, known as "short bowel syndrome" (or, sometimes, short gut syndrome) is rare, and is usually only found in patients who have less than 100 cm of the small intestine remaining after multiple surgeries.

Types of Nutritional Deficiencies

Crohn's patients may have trouble absorbing a large number of vitamins and nutrients including:


Calories are derived from macronutrients such as carbohydrates, protein and fat. If a person is losing weight, malabsorption may be the cause.


Patients on high-dose steroids such as prednisone, those with prolonged blood loss or diarrhea, and people with wounds or fistulas affecting the small bowel, may need to supplement their protein intake.


Individuals suffering from severe Crohn's ileitis or those who have had more than one meter of their ileum (lower small intestine) removed may require the addition of specific fats into their diets.


Because anemia is a common side effect of Crohn's disease, many patients require additional supplementation of iron.

Vitamin B12

People with extensive inflammation and/or removal of the ileum often require injections of vitamin B12.

Folic Acid

Patients on sulfasalazine will likely need to take folic acid as the medication affects the body's ability to metabolize folate. Also, patients with extensive Crohn's disease of the jejunum (middle portion of the small intestine) or those who have had their jejunum removed surgically will need to supplement their folic acid intake.

Potassium and Sodium

A patient who has had his colon (large bowel) surgically removed will need to increase his intake of both potassium and sodium as fluids and electrolytes are processed in the colon. There is an increased risk of potassium loss if a patient is suffering from chronic diarrhea and/or vomiting, or is taking prednisone.


Because steroids interfere with the absorption of calcium, patients being treated with them will likely need more of the mineral.

Vitamins A, D, E and K

Deficiencies in fat-soluble vitamins such as vitamins A, D, E and K are related to fat malabsorption and inflammation and/or removal of large portions of either the ileum or the jejunum. In addition, the medication Questran (or Cholestyramine) interferes with the absorption of vitamin D.


Patients with chronic diarrhea or those with extensive inflammation and/or removal of the ileum or jejunum may not be able to properly absorb magnesium, a key mineral for bone growth and other body processes.


?Patients may need to supplement zinc if they have either extensive inflammation and/or removal of the jejunum, if they have chronic diarrhea, or if they are taking prednisone.

Symptoms of Malabsorption

In severe cases of malabsorption, fatigue, weight loss or "foul smelling" diarrhea may occur.

Stool that is difficult to flush or leaves an "oil slick" on the surface of the bowl may be the result of malabsorption of fat. Most patients, however, will have either mild symptoms or no symptoms at all, so it is important for every Crohn's patient to have her doctor check for anemia or a vitamin deficiency.


Replacement of nutrients is usually an effective treatment for those suffering from nutritional deficiencies. An injection of vitamin B-12 can correct a B12 deficiency, while iron may be supplemented in either tablet or liquid form, etc.

Certain foods may make diarrhea or gas symptoms worse—especially during flare-ups. These include high-fiber foods such as beans, nuts and seeds, as well as greasy, fatty or fried foods.

Also, patients should avoid butter, heavy cream, and margarine and foods that cause gas including broccoli, cabbage, citrus fruits and spicy foods.

Individuals with an intestinal blockage may need to stay away from high-fiber foods such as raw fruits and vegetables entirely.

People with Crohn's are encouraged to eat a healthy, well-balanced diet, to eat small amounts of food throughout the day, and to drink plenty of water (also in small amounts throughout the day).