Malnutrition in Patients with Inflammatory Bowel Disease (IBD)

Malnutrition is common in people with inflammatory bowel disease (IBD), affecting up to 85% of patients, and is driven by reduced food intake, malabsorption and increased metabolic demands from chronic inflammation. Consequences of malnutrition include anemia, muscle wasting (sarcopenia),low bone density and multiple vitamin and mineral deficiencies, particularly of B12, folate, calcium and vitamin D. Regular screening and early nutritional support are essential for preventing complications and improving outcomes.

Inflammatory Bowel Disease & Malnutrition

Inflammatory bowel disease comprises a group of disorders that lead to chronic inflammation and irritation of the intestinal tract. The two most common conditions are Crohn’s disease (CD) and ulcerative colitis (UC).

Crohn’s disease is an autoimmune disorder that can impact the entire digestive system, leading to uncomfortable symptoms such as diarrhea, stomach cramps and abdominal pain. Ulcerative colitis specifically targets the colon, causing inflammation and ulcers that result in symptoms like bloody stool and abdominal cramping.

Since poor nutritional status and sarcopenia influence clinical outcomes, response to therapy and quality of life in patients with inflammatory bowel disease, effective nutritional rehabilitation is crucial for managing IBD.¹

How Common is IBD & Malnutrition?

It’s reported that up to 85% of individuals with IBD also suffer from malnutrition.² Discomfort and pain from gastrointestinal symptoms, along with complications like malabsorption and bacterial overgrowth can contribute to reduced food intake and worsen malnutrition in patients with inflammatory bowel disease.

What Causes Malnutrition in IBD?

The two main factors contributing to malnutrition in patients with inflammatory bowel disease are reduced food intake and malabsorption. These create a problematic cycle where patients eat too little and are unable to absorb enough nutrients from what little they consume. Inflammation related to these conditions can also further increase the body’s metabolic needs.

Reduction of Food Intake

Reduced food intake is the primary cause of malnutrition in patients with IBD. Those with active inflammatory bowel disease may experience nausea, vomiting, abdominal pain, diarrhea and other uncomfortable gastrointestinal issues, leading to a loss of appetite.

Patients with IBD may limit their diet to prevent flares or are frequently admitted to the hospital, which can result in long-term reduced food intake. Additionally, medications commonly used to treat inflammatory bowel disease can also cause nausea, vomiting or loss of appetite, further worsening decreased food intake.

Malabsorption

Malabsorption can result from various causes, including bowel resection surgery, bacterial overgrowth in the small intestine and chronic bowel inflammation.

Bowel Resection Surgery

Surgery significantly impacts nutrition absorption by causing diarrhea. Bowel resection surgery involves removing part of the small or large intestine. Small intestine resection leads to decreased digestion and nutrient malabsorption and may also reduce the intestinal uptake of bile acids, which can result in steatorrhea (fat malabsorption).¹

A partial colectomy (removal of part of the large intestine) is generally well tolerated but may lead to a slight increase in stool frequency due to decreased fluid absorption.

Small Intestinal Bacterial Overgrowth

A hallmark of inflammatory bowel disease is small intestinal bacterial overgrowth, which leads to nutritional malabsorption. 

Small intestinal bacterial overgrowth may contribute to increased intestinal permeability, reduce the digestion and absorption of nutrients and produce osmotically active metabolites that cause discomfort.¹Together, these can lead to faster gastrointestinal transit, which may result in malabsorption.

Chronic Bowel Inflammation

Chronic bowel inflammation can also lead to malabsorption by speeding up intestinal transit, which limits nutrient absorption and results in increased stool volume and diarrhea.¹

Malnutrition Complications in Patients with IBD

Malnutrition is a major factor leading to poor clinical outcomes in patients with inflammatory bowel disease.¹The severity of malnutrition varies depending on the duration, severity and activity of the disease. Common complications of malnutrition in IBD patients include anemia, sarcopenia, low bone mineral density and vitamin deficiencies.

Anemia

Anemia, an abnormally low number of red blood cells, is the most common extraintestinal sign of inflammatory bowel disease, affecting up to 70% of children, 42% of adolescents and 40% of adult patients.^1,3Inflammation, blood loss from the intestines, decreased iron absorption and altered iron metabolism all play a role in causing anemia in patients with IBD. Vitamin B12 deficiency can also lead to anemia, especially in those with Crohn’s disease due to involvement of the small intestine, particularly the ileum, where B12 is primarily absorbed.

Loss of Muscle Mass (Sarcopenia)

Loss of muscle mass is a key factor in evaluating patients with inflammatory bowel disease. Many IBD patients have reduced muscle mass, affecting up to 60% of them.¹ Among these patients, about 40% have a normal body mass index (BMI), while 20% are overweight or obese.¹

Many providers may not recognize these patients as undernourished using traditional measures, emphasizing the importance of screening all IBD patients for malnutrition even if they don’t have a low BMI or body weight.

Osteoporosis & Osteopenia

Up to 50% of patients with IBD also have low bone mass or osteoporosis (low bone mineral density) and have up to a 60% increased risk of fractures.^1,2 A combination of corticosteroid exposure, often used to treat Crohn’s and ulcerative colitis, along with chronic inflammation, lack of physical activity, sarcopenia and vitamin deficiencies, contributes to low bone mass and density.¹

Vitamin Deficiencies

Patients with inflammatory bowel disease are often low in both folic acid, vitamin B12 and other vitamins.

Low Folic Acid (Vitamin B9 or Folate)

Folic acid deficiency is common in patients with inflammatory bowel disease, affecting around 9% of patients with ulcerative colitis and 29% of patients with Crohn’s disease.¹

Folate is typically caused by inadequate dietary intake and/or malabsorption.¹  It can also be caused by pharmaceutical interventions like sulfasalazine and methotrexate, medications used to treat these conditions, which inhibit folate absorption.¹

Low folate can lead to hyperhomocysteinemia (excessive homocysteine), and markedly elevated levels of homocysteine can put patients at risk for cardiovascular disease and may contribute to arterial and venous thromboembolic events.

 Folate deficiency is also a risk factor of colorectal cancer in patients with IBD.¹

Low Vitamin B12

Patients with IBD are also at risk for vitamin B12 deficiency. It is most common in patients with Crohn’s disease, since absorption relies on the ileum.¹Patients with CD who have had an ileum resection greater than 60 centimeters often develop low B12 levels and require lifelong B12 supplementation.¹ 

Other Vitamin Deficiencies

Patients with IBD are also at risk for other vitamin deficiencies, including calcium, vitamin D, magnesium vitamin A, zinc and vitamin K.

Treating Malnourished Patients with IBD

Screening & Correcting Vitamin Deficiencies

Screening patients with IBD, especially if they’ve undergone a resection surgery, is important to avoid clinical complications. Patients who have gotten an ileal resection greater than 20 centimeters should be given B12 replacement and patients with an ileal resection of less than 20 centimeters should receive yearly monitoring.⁴

Because of the implications of vitamin D and calcium on bone mass and bone mineral density, serum calcium and 25(OH) vitamin D should be monitored and supplemented. Adequate vitamin D may also benefit Crohn’s disease.

Other vitamin deficiencies should be monitored and supplemented as necessary.

Nutrition Therapy

In patients with reduced oral food intake, enteral nutrition (EN) therapy, alongside oral nutritional supplements, may be necessary. EN is the preferred method of nutrition therapy over parenteral nutrition (PN) for its lowered incidence of complications.¹

Parenteral nutritional is beneficial for patients with short bowel syndrome with severe malabsorption that cannot be managed with EN. It also recommended for patients with obstructive disease where feeding tube placement has failed or cannot be placed past the obstruction while awaiting more definitive intervention (such as surgery) and could also be considered short-term for individuals experiencing symptomatic flare ups.

Physical Therapy

Physical therapy can play a key role in treating sarcopenia, especially in individuals with chronic conditions like IBD. Targeted strength training, resistance exercises and functional movement can help rebuild muscle mass, improve balance and restore mobility.

Get Help for Malnutrition

If you or a loved one is struggling with malnutrition due to Crohn’s disease or ulcerative colitis, you’re not alone. Specialized medical care can address nutrient deficiencies, support healing and improve long-term outcomes. Don’t wait to get the support you need.

Start with a free assessment.

References

1. Balestrieri, P., Ribolsi, M., Guarino, M. P. L., Emerenziani, S., Altomare, A., & Cicala, M. (2020). Nutritional aspects in inflammatory bowel diseases. Nutrients, 12(2), 372. https://doi.org/10.3390/nu12020372
2. Lucendo, A. J., & De Rezende, L. C. (2009). Importance of nutrition in inflammatory bowel disease. World Journal of Gastroenterology, 15(17), 2081. https://doi.org/10.3748/wjg.15.2081
3. Goodhand, J. R., Kamperidis, N., Rao, A., Laskaratos, F., McDermott, A., Wahed, M., Naik, S., Croft, N. M., Lindsay, J. O., Sanderson, I. R., & Rampton, D. S. (2011). Prevalence and management of anemia in children, adolescents, and adults with inflammatory bowel disease. Inflammatory Bowel Diseases, 18(3), 513–519. https://doi.emiaanorg/10.1002/ibd.21740
4. Mowat, C., Cole, A., Windsor, A., Ahmad, T., Arnott, I., Driscoll, R., Mitton, S., Orchard, T., Rutter, M., Younge, L., Lees, C., Ho, G., Satsangi, J., & Bloom, S. (2011). Guidelines for the management of inflammatory bowel disease in adults. Gut, 60(5), 571–607. https://doi.org/10.1136/gut.2010.224154