How does refeeding cause constipation?

From the Guidelines

Refeeding can cause constipation due to reduced intestinal motility, low-fiber diets, fluid shifts, and electrolyte imbalances, and managing it requires ensuring adequate hydration, gradually increasing dietary fiber, and considering gentle stool softeners or osmotic laxatives as needed. When refeeding begins, the digestive system needs time to readjust to processing food again, and the intestines may have reduced motility from disuse during starvation, making it difficult to move stool through the digestive tract 1. Additionally, refeeding often involves careful caloric control with diets that may be low in fiber initially, contributing to harder stools. Fluid shifts during refeeding can lead to dehydration as nutrients are absorbed, further hardening stool. Electrolyte imbalances, particularly low potassium and magnesium levels that commonly occur during refeeding, can impair intestinal muscle function 1.

To manage refeeding-associated constipation, it is essential to:

• Ensure adequate hydration
• Gradually increase dietary fiber as tolerated
• Consider a gentle stool softener like docusate sodium (100-300 mg daily)
• Maintain physical activity as appropriate Severe cases may require osmotic laxatives such as polyethylene glycol (17g in 8oz water daily) 1. These interventions help support normal bowel function while the digestive system recovers its normal motility patterns during the refeeding process. It is also crucial to monitor and substitute electrolytes, such as potassium, phosphate, and magnesium, as necessary, to prevent refeeding syndrome 1.

In terms of specific recommendations, the most recent and highest quality study suggests that increasing fluid intake and physical activity, and adding dietary fiber, can help manage constipation 1. Furthermore, the use of peripherally acting μ-opioid receptor antagonists, such as methylnaltrexone, may be considered for opioid-induced constipation 1. However, it is essential to prioritize the most recent and highest quality evidence, and in this case, the study by 1 provides the most up-to-date guidance on managing constipation during refeeding.

From the Research

Refeeding Syndrome and Constipation

• Refeeding syndrome is a potentially fatal condition that can occur when nutrition is reintroduced after a period of starvation or malnutrition 2, 3, 4, 5.
• The syndrome is characterized by severe electrolyte disturbances, including hypophosphatemia, hypokalemia, and hypomagnesemia, as well as metabolic abnormalities 6, 2, 4, 5.
• While the exact mechanism of refeeding syndrome causing constipation is not explicitly stated in the provided studies, it can be inferred that the electrolyte imbalances and metabolic changes associated with refeeding syndrome may contribute to constipation.
• For example, hypokalemia (low potassium levels) can cause muscle weakness and decreased bowel motility, leading to constipation 2, 4.
• Additionally, the rapid changes in nutrition and electrolyte levels during refeeding can disrupt the normal functioning of the gut, leading to constipation or other gastrointestinal symptoms 3, 5.

Prevention and Management of Refeeding Syndrome

• To prevent refeeding syndrome, it is recommended to start with a low-calorie diet and gradually increase the calorie intake over time 2, 3.
• Electrolyte supplements, such as phosphate, magnesium, and potassium, should be administered concurrently with refeeding to prevent deficiencies 6, 2, 4, 5.
• Close monitoring of patients at risk of refeeding syndrome is crucial to prevent and manage the condition 2, 3, 4, 5.
• A multidisciplinary approach to nutrition management, including careful patient monitoring and teamwork, can help to reduce the risk of refeeding syndrome and its complications, including constipation 4.