From the Guidelines
Soluble fiber is the most effective type of fiber for managing diarrhea, as it absorbs excess water in the intestines and forms a gel-like substance that slows down bowel movements and adds bulk to loose stools. According to the British Society of Gastroenterology guidelines on the management of irritable bowel syndrome 1, soluble fibre, such as ispaghula, is an effective treatment for global symptoms and abdominal pain in IBS, and should be commenced at a low dose (3–4 g/day) and built up gradually to avoid bloating. Good sources of soluble fiber include psyllium husk (Metamucil), methylcellulose (Citrucel), oatmeal, bananas, and applesauce.
When using fiber to manage diarrhea, it's essential to:
- Start with small amounts of soluble fiber, such as 1 teaspoon of psyllium husk mixed in water once daily, gradually increasing to 1 tablespoon up to three times daily as tolerated 1
- Drink plenty of fluids (at least 8 glasses of water daily) when increasing fiber intake to prevent constipation
- Avoid insoluble fiber (found in wheat bran, whole grains, and many vegetables) as it may worsen diarrhea in some cases
- Gradually introduce fiber supplementation to allow the body to adjust, especially in cases of chronic diarrhea
The AGA clinical practice update on the role of diet in irritable bowel syndrome also recommends reviewing fiber intake and adjusting it while monitoring the effect on symptoms, and discouraging the consumption of insoluble fiber 1. By following these guidelines and incorporating soluble fiber into their diet, individuals with diarrhea can effectively manage their symptoms and improve their quality of life.
From the Research
How Fiber Helps with Diarrhea
- Fiber can help with diarrhea by adding bulk to the stool and helping to firm it up, making it easier to pass and reducing the frequency of bowel movements.
- However, the provided studies do not directly discuss the role of fiber in helping with diarrhea.
- The studies focus on the use of probiotics in the prevention and treatment of diarrhea 2, 3, the management of chronic diarrhea in primary care 4, the clinical approach to diarrhea 5, and the diagnosis and management of chronic diarrhea 6.
- There is no direct evidence in the provided studies to support the use of fiber in helping with diarrhea.