AGA issues guidance on diet, nutrition in IBD

All patients with inflammatory bowel disease (IBD) should be monitored for vitamin D and iron deficiency, and those with extensive ileal disease or prior ileal surgery (i.e., resection or ileal pouch) should be monitored for vitamin B₁₂ deficiency, according to updated guidance from the American Gastroenterological Association (AGA).

The clinical practice update was developed by the AGA to provide best practice advice on the role of diet and nutritional therapies in the treatment of patients with IBD. The statements were based on review of the existing literature combined with expert opinion.

Unless contraindicated, all patients with IBD should be advised to follow a Mediterranean diet for their overall health and well-being, the update said. It noted that no diet has consistently been found to decrease rates of flares in adults with IBD and that while a diet low in red and processed meat may reduce flares in ulcerative colitis, it has not been found to reduce relapse in Crohn's disease.

Patients with IBD who have symptomatic intestinal strictures may not tolerate fibrous, plant-based foods such as raw fruits and vegetables because of their texture, the update said. However, patients may be able to incorporate a wider variety of these foods into their diets with an emphasis on careful chewing, cooking, and processing to achieve a softer and less fibrinous consistency, the authors noted.

All patients with IBD should be screened regularly by their clinician for malnutrition, the update said. Signs and symptoms included unintended weight loss, edema and fluid retention, and fat and muscle mass loss. "When observed, more complete evaluation for malnutrition by a registered dietitian is indicated," the update stated. "Serum proteins are no longer recommended for the identification and diagnosis of malnutrition due to their lack of specificity for nutritional status and high sensitivity to inflammation."

The update noted that all patients with complicated IBD should be comanaged with a registered dietitian, especially those with malnutrition, small bowel syndrome, or enterocutaneous fistula, as well as those who require more complex nutrition therapies (e.g., parenteral nutrition, enteral nutrition, or exclusive enteral nutrition) or are on a Crohn's disease exclusion diet. In addition, the update suggested that all newly diagnosed patients with IBD have access to a registered dietitian.

"Dietary advice needs to be tailored to an individual IBD patient's nutritional status and goals, which will vary over time," the update concluded. "Implementing the more complex nutritional strategies for IBD management will be best achieved by means of collaborative interdisciplinary practice between gastroenterologists and registered dietitians."

Additional best practice advice statements covered the role of exclusive and partial enteral nutrition in IBD, including to induce remission and before surgery, and the potential of breastfeeding in childhood and a healthy balanced Mediterranean diet low in processed foods to lower IBD risk. The clinical practice update was published Jan. 23 by Gastroenterology.