Total proctocolectomy with ileal pouch anal anastomosis (IPAA) is the surgery of choice for patients with refractory Ulcerative Colitis (UC). Following the first-year post operatively the pouch is adapted to the ileal content efflux and most patients have 5-8 bowel movements a day and one nocturnal. Stool and gas incontinence, episodic nocturnal soiling and use of anti-diarrheal medications are common1–4. Since patients often relate symptoms to food (especially fruit and vegetable, dairy products and spicy foods), food avoidance is prevalent in up to 70% of the patients5. Therefore, patients after pouch surgery should be routinely assessed and treated by a dietitian within the setting of a multidisciplinary team6.
Nutritional deficiencies including iron, vitamin B12 and vitamin D are common and should be monitored and addressed7. Fluids and electrolytes imbalances are common in patients with increased number of bowel movements and need to be managed in order to avoid dehydration.
Alongside functional considerations of pouch surgery, the most long-term complication is pouchitis, inflammation of the small bowel8. The definition is based on clinical, endoscopic and histologic criteria, comprising the pouchitis disease activity index (PDAI). Several dietary interventions in small numbers of patients were reported. These were associated with symptomatic improvement. Exclusive enteral nutrition for four weeks resulted in reduction of mean stool frequency from 12 to 6 and decreased median clinical PDAI from 4 to 1, in seven patients with pouchitis.9 In addition, a pilot study of 13 patients after pouch surgery found high rate of carbohydrate malabsorption including lactulose, fructose and lactose. The researches demonstrated that low FODMAP diet reduced median stool frequency from 8 to 4 in patients without pouchitis, however this intervention did not improve symptoms in patients with pouchitis10. Therefore, low FODMAP diet may be considered in patients with inactive disease and functional component.
Diet may also play a role in the pathogenesis of pouchitis via altering bacterial11,12 or fungal13 microbial composition. Low fruit and vegetable consumption was shown to be associated with lower microbial diversity and with the development of pouchitis5,11; moreover, fruit consumption correlated with the abundance of beneficial microbial groups including Faecalibacterium, Lachnospira and a genus from the Ruminococcaceae family. Thus, fruit and vegetable consumption should be recommended for patients after pouch surgery.
The role of probiotics was also investigated in pouchitis. Three small double-blind placebo controlled trials demonstrated the effectiveness of a multi-strain probiotic mixture containing a combination of lactic acid bacteria, streptococcus and bifidobacteria in maintaining remission14,15 and preventing the onset of pouchitis16. Therefore, according to the ESPEN guidelines 2017, probiotic therapy can be considered for primary or secondary prevention of pouchitis17. Data regarding prebiotic supplementation in pouchitis are limited.
To summarize, patients after pouch surgery should be referred to a dietitian as a part of the multidisciplinary team. Nutritional evaluation including nutritional status, nutritional deficiencies, dietary strategies to manage symptoms or prevent unnecessary food avoidance that may lead to an imbalanced diet should be addressed. As diet is an important environmental factor, microbiota targeted dietary interventions should be further investigated as management and prevention strategies of pouchitis.