An ileal pouch-anal anastomosis (IPAA) is the preferred surgical reconstruction for restoration of intestinal continuity after a total proctocolectomy; it obviates the need for a permanent ileostomy. The pouch, or continuity reservoir, is anastomosed to the sphincter-spared anus allowing for controlled passage of bowel movements (BMs). Patients with mature, properly functioning pouches can expect to pass 6-8 BMs every 24 hours. Diet after IPAA is empiric and patient-specific with the overarching goals to optimize pouch continence and nutrient/fluid absorption. Pouch inflammation is common and thought to be primarily related to an abnormal immune response to pouch dysbiosis.1 Diet may play an important role in mediating the dysbiosis and influence pouch function, though evidence of this is lacking. This article will review basic information regarding IPAA, pouch complications, diet for patients with IPAA, and recommendations for long-term micronutrient supplementation.
Introduction
Restorative proctocolectomy with ileal pouch-anal anastomosis (IPAA) is the surgical procedure of choice for patients with refractory ulcerative colitis (UC) and familial adenomatous polyposis (FAP) who desire intestinal continuity after colectomy. The pouch is an alternative to a permanent end ileostomy. The most common pouch configuration is the J-shape (constructed from two limbs of distal ileum, Figure 1), though other configurations are possible based on the surgeon’s determination. To date there is a dearth of evidence to support specific dietary recommendations for patients with IPAA. Frequently, results of small studies with heterogeneous populations and endpoints, or recommendations based on patients’ observations of their responses to certain foods/food components, are used to make generalized dietary recommendations. This review will summarize the limited data and key expert recommendations to support nutrition therapies for patients with IPAA.
IPAA Construction and Function
The IPAA procedure is typically performed in two or three phases depending on the condition of the colon, specifically, and patient’s overall condition.2,3 Approximately 30-40 centimeters of the distal ileum is used to fashion the pouch that is then anastomosed to the sphincter-spared anus.4 The two-step procedure is most commonly performed; the first phase is the proctocolectomy and IPAA construction with a diverting ileostomy (DI) followed 6-8 weeks later by the second step of DI takedown.3 The three-step procedure is often reserved for patients with severe colitis, perforation, bleeding, or dysplasia; the first step is a subtotal colectomy with end ileostomy, the second step is the completion proctectomy, IPAA construction with DI and takedown of the end ileostomy, and the third step is the takedown of the DI.
Once bowel continuity is restored, patients will experience a period of intestinal adaptation during which their bowel habits and dietary tolerance evolve. The adaptation process can take 6-18 months following colectomy.6,7 After complete adaptation, patients can expect to pass an average of 6 bowel movements (BMs) per 24 hours; often 1 BM will occur overnight.6 Physical and emotional adjustments to the new pouch habits will vary between patients. Those with a history of severe colitis often pass fewer BMs and feel better with the pouch, however, patients with FAP typically do not have pre-operative gastrointestinal symptoms and must learn to cope with frequent BMs, reduced continence, and fecal urgency after the proctocolectomy. In either scenario, support from an experienced gastrointestinal registered dietitian nutritionist (RDN) will help patients to understand the relationships between diet, hydration, and pouch function to optimize their health and quality of life (QoL).
IPAA Complications
The IPAA procedure is not without risk of complications; Table 1 lists the phenotypes of pouch disorders. In the acute post-operative phase infection/pelvic abscess, anastomotic leak, and small bowel (SB) obstruction/ileus are most commonly observed; complication rates are higher for patients who received systemic corticosteroids or smoked at the time of surgery.8 Long term complications are characterized by urgency/high frequency of BMs, continence problems (both seepage and difficult evacuation), fatigue, pouch failure, and reduced QoL.3
Pouch inflammation (pouchitis) is the most common complication associated with an IPAA and affects 30–50% of patients.9 Acute pouchitis is defined as symptoms lasting < 4 weeks and is usually responsive to antibiotic therapy whereas chronic pouchitis lasts > 4 weeks. An approach to diagnosis and management of pouchitis was recently published in this journal.10
The etiology of pouchitis is not fully understood and is likely multifactorial but thought to be primarily related to an abnormal immune response to pouch dysbiosis; though secondary factors such as Crohn’s disease, infection, ischemia, or radiation can also cause inflammation.1
Diet After IPAA
The goals of nutrition therapy for patients with IPAA are to optimize SB absorption and to regulate passage of BMs. Patients may report that their pouch function and defecation frequency are directly related to meals and post-prandial gastrointestinal motility; though evidence is lacking with regard to specific dietary elements that directly affect pouch function.7,11 Therefore, patients and clinicians alike must take a flexible and empiric approach when developing meal plans because a patient’s food tolerances will likely change with pouch adaptation and in cases of dysfunction.
| Phenotype | Clinical Features |
| Structural | Anastomotic leak Fistula Pelvic infection/abscess Obstruction Dilation Bezoar |
| Inflammation | Pouchitis (acute, chronic antibiotic-responsive, chronic antibiotic-refractory) Crohn’s disease-like pouch inflammation Cuffitis |
| Functional | Irritable pouch syndrome Dysmotility Anopouch pain syndrome |
| Nutrition/metabolic | Anemia Metabolic bone disease Micronutrient deficiencies |
Immediately after DI takedown, depending upon the surgeon’s opinion of the competence of the pouch and pouch-anal anastomosis, it may be recommended for the patient to follow a low fiber diet. Although evidence lacks for fiber restriction, of particular concern to surgeons are insoluble fibers (e.g., wheat or oat bran, vegetable/legume peels/shells, nuts, and seeds) that accelerate transit, increase stool bulk, and exert pressure on suture lines. Fiber restrictions should be limited to the least number of weeks necessary to prevent patients from indefinite adherence to a low fiber diet.
Beyond the initial postoperative period, IPAA patients should advance their diet as tolerated to one that is balanced between all food groups. General guidelines for an “IPAA Diet” are lacking given significant variations in patients’ perceived tolerance to foods (see Table 2 for foods observed to effect pouch output; patients can include or limit foods based on their pouch function).7,12,13 After total colectomy absorption of nutrients and fluid is limited to the SB, thus application of the following generally accepted recommendations for those with an ileostomy may help to slow postprandial gastric emptying and intestinal transit for optimal absorption:14,15
Eat multiple (5-6) small meals daily to avoid excessive gastric and pouch distention
Include slowly fermented, gel-forming fiber (e.g., psyllium) with each meal
Avoid simple sugars in foods and beverages to reduce rapid gastric emptying of hypertonic fluid
May limit intake of lactose containing foods and beverages
Separate solid foods and liquids to optimize gastric digestion
Post-prandial rest for 20-30 minutes to increase gastric digestion and to reduce intestinal motility
Sip isotonic or hypotonic fluids between meals
Oral rehydration solutions (ORS) can promote SB absorption of sodium and water
Avoid eating 2-3 hours before bed to reduce nocturnal defecation
If needed, take antimotility medications 20-30 minutes before meals and at bedtime
See Table 3 for more detailed interventions to improve absorption after IPAA.
Over time, patients with a well-functioning pouch may be able to tolerate larger, less frequent meals. Although evidence is limited, ingestion of foods with gel-forming fibers (psyllium, pectin, gums) may help to increase the consistency of stool and provide important substrate for microbial fermentation and production of important metabolites.14,16 A recent study looked at fruit consumption after IPAA and found that consumption of > 1.5 fruit servings daily reduced the risk of developing pouchitis,17 supporting the importance of dietary fiber consumption after IPAA.
The Mediterranean diet (MD) is known for its emphasis on plant-based foods, fish and olive oil while limiting intake of red meats, saturated fats, sweets, and sugary beverages. Research has demonstrated that the MD can reduce inflammation in chronic disease states.18 More recently, a study demonstrated that patients with IPAA (for UC) who followed the MD for 8 years had reduced fecal calprotectin levels and adherence was inversely associated with episodes of pouchitis.19 Although the exact mechanism is not understood, this data supports the recommendation that IPAA patients follow a MD pattern (Figure 2) to maintain optimal pouch function.
Diet and Pouch Dysfunction
Pouch dysfunction can derail any progress a patient has made towards attaining a stable, healthy diet. In the case of pouchitis the combination of medical therapies (typically antibiotics are the first line of therapy as pouchitis is thought to result from microbial dysbiosis) and a shift of diet composition may provide patients symptomatic relief.1 A recent pilot study of 15 adults with active pouchitis identified a positive effect of the Crohn’s Disease Exclusion Diet (excludes processed and refined foods, includes resistant starch and fiber) in patients with strict adherence.20 Although the study was small, non-randomized, and uncontrolled, it seems hopeful that some cases of pouch inflammation may respond to diet therapy. As more is understood about the phenotypes of dysfunction, and the association between pouch function and the microbiome, it is likely that there will be opportunities for 1:1 counseling with a RDN to tailor the diet based on the nature of the pouch dysfunction and create more evidence-based recommendations for dietary therapies to alter active inflammation.7,14
In patients with pouch dysfunction that is more irritable in nature (frequent and/or urgent BMs, abdominal cramps, pelvic discomfort, and absence of inflammation),21 it may be reasonable to restrict highly fermentable and osmotically active carbohydrates with a low FODMAP diet (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols).14 Limitation of FODMAP consumption may reduce bacterial fermentation (gas production) of undigested carbohydrates, as well as decrease water delivery to the pouch, both of which can reduce symptoms of gas, bloating, and diarrhea/urgency. Patients with a positive response to the initial exclusion of FODMAPs should work intensively with a RDN to identify trigger foods and to re-introduce those foods that are tolerable. There is minimal evidence though to support FODMAP restriction in the management of pouchitis.22
| Observed Effects of Food | Foods and Beverages |
| Stool thickening | Applesauce Banana Bread Pasta Potatoes Oatmeal Rice Peanut butter Soluble, low fermentable fiber (e.g., psyllium) |
| Stool thinning | Spicy foods (capsaicin) Fruit and fruit juice Cabbage |
| Increased stool output | Nuts Corn Chocolate Lettuce Fresh oranges Tomatoes Cow’s milk Alcohol Fried foods Spicy foods |
| Increased flatus | Food with high FODMAPs Onions, cabbage, and cow’s milk Spicy foods |
| Perianal irritation | Citrus fruits Spicy foods Nuts and seeds |
Fluids and Hydration
Hydration status after IPAA is often overlooked. Chronic low-level dehydration (characterized by low 24-hour urine volume, hypotension, chronic fatigue, dry mucous membranes, etc.) can affect a patient’s overall feeling of wellness and their ability to participate in life activities, not to mention the risk of nephrolithiasis and chronic kidney injury. It is recommended for adults with normal kidney function to produce at least 1,000-1,200 mL urine per day and kidney stone formers should make at least 1,500 mL per day.23,24 Attention to both fluid intake and urine output is imperative to gauge hydration and ensure long-term maintenance of normal kidney function. Without the colon to absorb sodium and water, those with an IPAA must rely mainly on SB sodium-glucose co-transporters to drag water across the mucosa.25 Consumption of isotonic fluids such as ORS and avoidance of hypertonic, sugary beverages should improve water absorption and hydration status.
ORS contain specific concentrations of sodium and sugar in water and are known to facilitate SB water absorption. Beverages that contain both sodium (50-70 mEq/L) and glucose (20-40g/L) are palatable options (Table 3).26 IPAA patients who pass high volume stool may find that sipping ORS between meals can help to achieve hydration goals.
Micronutrients
The IPAA consensus guidelines recommend lifelong monitoring of several micronutrients as well as for anemia and metabolic bone disease.1 Most notably, vitamin B12, vitamin D, and iron, are identified as micronutrients of potential concern (particularly in the early phase of IPAA and in the setting of pouch inflammation),1 although other fat soluble vitamins and divalent cations may become deficient in the IPAA population (see Table 4).4 Deficiencies can result from insufficient intake and with altered absorption in the setting of rapid transit or of villous atrophy associated with pouch inflammation.4 In particular, vitamin B12 deficiency can develop from reduced absorption and increased utilization by bacteria if pouch overgrowth/dysbiosis exists.4 Vitamin B12 deficiency can lead to permanent neurological deficits and therefore lifelong therapeutic dosing of cyanocobalamin (1,000 mcg by mouth daily or monthly subcutaneous injection) is safe and recommended.
Evidence for monitoring and supplementation of micronutrients after IPAA does not exist. Data and guidelines for patients with inflammatory bowel disease and post-surgical malabsorption can guide clinicians when prescribing supplementation regimens. One important factor with respect to interpretation of serum/plasma micronutrient levels when inflammation exists is that reported levels are often perturbed making interpretation difficult.27 A RDN with experience in micronutrient repletion therapy, who is able to perform sequential nutrition focused physical exams, is the ideal team member to develop, institute, and monitor responses to micronutrient supplementation. Short of this, it is prudent for anyone unable to consume a balanced diet to take a daily multivitamin with mineral supplement that meets 100% of the Reference Dietary Intake (RDIs).
| Therapy | Intervention |
| Diet | Eat 5-6 small meals Avoid overeating/drinking to prevent excessive pouch distention Use the Mediterranean diet pattern to structure meals Include plenty of plant foods with soluble fiber Oats, peas, carrots, beans, citrus fruits, apple, banana Slows gastric emptying, thickens stool, supports microbiome Eat at least two fruit servings daily Limit foods with simple sugars Cakes, cookies, pastries, ice cream, Italian ice Limit greasy foods Limit insoluble fiber, caffeine, and alcohol May increase BM frequency and cause watery stool |
| Fluids | Limit fluids at meals to 4-8 ounces Sip remaining fluids between meals, throughout the day Focus in hypotonic and isotonic fluids for SB water absorption Hypotonic beverages – water, dilute juices, tea, coffee, diet drinks Isotonic beverages – ORS, e.g., Ceralyte®, Pedialyte®, DripDrop®, Trioral® Limit hypertonic beverages Cause osmotic shift of water into the intestinal lumen resulting in more volume to reabsorb Fruit juice, sweet tea, lemonade, sweetened beverages, and cocktails Oral nutrition supplements (Ensure®, Boost®) |
| Medications and supplements | Use antimotility agents such as loperamide to slow gastrointestinal transit Time antimotility medications 30-60 minutes before meals and bedtime Fiber supplements such as Metamucil® or Benefiber® may help thicken stool for improved continence |
| Activity | Sit for 20-30 minutes after meals to allow for digestion and reduce intestinal motility Avoid eating 2-3 hours before bed to reduce nocturnal defecation |
| Micronutrient | Monitoring Parameters | Daily Maintenance Dose¥ (Oral) | Repletion Dose* |
| Vitamin B12 | Serum vitamin B12 Serum folate Plasma homocysteine Plasma methylmalonic acid | 1,000 mcg | 1,000 mcg subcutaneous injection for 5-7 days |
| Vitamin D | Serum 25-hydroxy vitamin D | 18 – 70 yrs 15 mcg > 70 yrs 20 mcg | 100-125 mcg oral daily |
| Vitamin E | Plasma α-tocopherol | 15 mg | 90 – 180 mg oral daily |
| Vitamin A | Serum Retinol | Men 900 mcg Women 700 mcg Pregnant 770 mcg Lactating 1300 mcg | 1,500 – 3,000 mcg oral daily |
| Iron | Hemoglobin Serum iron Total iron binding capacity Transferrin saturation Serum ferritin | Men 8 mcg Women Premenopausal 18 mg Postmenopausal 8 mg | 50 – 200 mg oral daily (divided doses) |
| Zinc | Plasma zinc | Men – 11 mg Women – 8 mg | 50 mg oral daily |
| Calcium | Bone density | Men 19 – 70 yrs 1,000 mg >70 yrs 1,200 mg Women 19-50 yrs 1,000 mg >50 1,200 mg | Variable based on bone health |
Conclusion
For patients with severe colitis or FAP the IPAA is a means to restore bowel continuity and avoid a permanent end ileostomy after total proctocolectomy. The procedure requires patients to adopt balanced dietary patterns, such as the MD, that include fruits, vegetables, and fiber to optimize pouch function, absorption, the microbiome, and overall health. Avoidance of excessive pouch distention from over-eating/drinking may help to control the frequency of BMs. Symptoms of irritable pouch syndrome (diarrhea dominant), rather than inflammation, may be controlled with elimination of some highly fermentable carbohydrates. Collaboration between the patient and a RDN is necessary to identify poorly tolerated foods and design the most balanced diet possible. Routine supplementation with vitamin B12 and close monitoring for micronutrient deficiencies, anemia, bone health, and hydration status is essential to ensuring optimal health and well-being. In summary, the IPAA can significantly improve the health and QoL for some patients but may require ongoing RDN support for optimization of nutrient uptake, hydration, and pouch function.
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