January, 2007

A Dietary Challenge: Maximizing Bowel
Adaptation in Short Bowel Syndrome
By Theresa A. Fessler, MS, RD, CNSD
Today’s Dietitian
Vol. 9 No. 1 P. 40

Mr. R. has a history of Crohn’s disease and has had several bowel surgeries, including colectomy, over the past 15 years. He has only approximately 120 centimeters of small bowel remaining, with an ileostomy that drains 2 to 3 liters per day. Mrs. W. at age 39, has undergone a resection of malignant tumors in her abdomen. Because of mesenteric tumor involvement, she had a partial colectomy and her small bowel is less than one third of its previous length.

Had these situations occurred 40 years ago, these patients would have died due to inability to maintain nutrition or hydration. But today, with the routine use of parenteral nutrition (PN), these patients can survive and even hope for enough adaptation of their remaining bowel to maintain a normal life on oral nutrition.

It is easy to initiate PN therapy, but it takes a skilled dietitian to help a patient successfully wean off of it. Depending on the amount of bowel remaining, some patients with short bowel syndrome (SBS) can advance to an oral diet and eventually wean off of PN support. The RD is instrumental in recommending early oral diet advancement and guiding the patient toward appropriate choices that will help maximize bowel adaptation minimize complications.

SBS results when a patient lacks sufficient bowel length or function to support nutrient needs. This occurs after massive intestinal resection, more commonly in Crohn’s disease, mesenteric infarction, traumatic abdominal injuries, or malignant abdominal tumors.1-3

Reduced intestinal length and decreased transit time result in nutrient malabsorption and fluid losses, evident as diarrhea or increased ostomy output when oral intake is increased.
Patients who have 150 centimeters or more of remaining small bowel without a colon, or 60 to 90 centimeters of small bowel with a colon, will initially require PN and may be able to transition to oral nutrition over a period of one to two years after surgery.4 The ability for the gastrointestinal (GI) tract to adapt, as well as dietary and medication needs, depends on the length of remaining jejunum and/or ileum and whether the colon is present. Successful adaptation is more likely in patients whose colon remains and varies with the patient’s age, presence or absence of ileocecal valve, whether or not there is disease of the remnant small bowel, and condition of the stomach, liver, and pancreas. Patients with less than 100 to 140 centimeters of small bowel and no colon will likely need either intestinal transplantation or lifetime PN support.3,4

Laura Matarese, MS, RD, LDN, FADA, CNSD, director of nutrition, Intestinal Rehabilitation and Transplant Center, at the University of Pittsburgh Medical Center, says, “Complex luminal nutrients are the most potent stimuli to bowel adaptation. Thus, it is very important to try to get the patient to eat food as soon as possible and decrease the reliance on specialized enteral formulas or parenteral nutrition.” The obstacle that is most detrimental to successful adaptation is failure to use the GI tract.

Neha Parekh, MS, RD, LD, CNSD, director of nutrition at the Cleveland Clinic’s Intestinal Rehabilitation Program adds, “Long-chain fats, oligopeptides, and polysaccharides found in oral diets and in standard enteral formulas all have a more favorable effect on bowel adaptation than their more hydrolyzed counterparts.”

Medications are an important part of SBS treatment. Carol Rees Parrish, RD, MS, GI nutrition support specialist at the University of Virginia Health System, states, “Without the appropriate use of medications in these patients, we would have a difficult time transitioning them off of PN.”

Excessive gastric secretions and intestinal hypermotility are problematic in SBS. Histamine antagonist (H2 Blocker) or proton pump inhibitor medications are used to control the volume and pH of excess gastric fluid. Excess acid can injure bowel mucosa and interfere with digestion by denaturing pancreatic enzymes and hindering bile salt function. Most patients with SBS will require antidiarrheal medications, especially those who have had resection of ileum, ileocecal valve, or colon. Octreotide injections are sometimes used in those who lack sufficient small bowel to absorb oral antisecretory medications, but its use should be limited to those with high diarrhea /stoma output that other medications have failed to control.5,6 The ileum is the site for enterohepatic recirculation of bile salts. For patients who have less than 100 centimeters of ileum, with colon remaining, unabsorbed bile salts can cause a secretory diarrhea. Cholestyramine is sometimes used to bind bile salts to prevent this type of diarrhea.5,6

In the months following bowel surgery, PN is lifesaving as the major source of nutrition and hydration until the patient’s remaining bowel adapts. PN should be adjusted to meet the patient’s fluid, electrolyte, vitamin, mineral, trace element, energy, and protein needs. In situations of high ostomy output, more fluid volume, sodium, magnesium, and zinc will be needed to offset losses.7 In calculating PN volume and content, the dietitian should check for changes in the patient’s weight, energy levels, stool or ostomy output, urine output, and complaints of thirst.

The amount of PN can be decreased when the patient demonstrates ability to take oral nutrition without excessive stool or ostomy output with appropriate weight maintenance or gain. To maintain fluid and electrolyte balance, a goal for ileostomy output is 1 to 1.5 liters per day. For weaning, Matarese suggests taking the patient off PN for one day and monitoring urine output, ensuring that it is at least 1 to 2 liters per day. Monitor blood chemistry—if normal, the patient can skip another day of PN, but the days skipped should not be consecutive. Many patients will be able to decrease PN from daily to every other day during the weaning process.

Diet Modification
Parekh described one of her favorite cases: A 47-year-old man with a massive inguinal hernia was awaiting scheduled surgery but had to be taken emergently to the operating room for ischemic bowel. The surgeon performed an extensive small bowel resection with primary anastamosis, hernia repair, and evacuation of a ruptured mesenteric hematoma. The operative report indicated that he had approximately 30 centimeters of jejunum and ileum attached to his ileocecal valve and colon. PN therapy was expected to be necessary, but central venous catheter placement was not done because the patient had panic attacks prior to placement attempts.

Parekh says, “I ended up working with him extensively for two weeks, providing him with low fat, no concentrated sweets, six small meals per day diet instruction, along with antidiarrheal and antisecretory medications, pancreatic enzymes, oral rehydration solution, soluble fiber, and oral vitamin and mineral replacement therapies. He was able to go home within three weeks of surgery without home intravenous fluids or PN. It has been almost a year now, and he has lost some weight but has stabilized and is very happy with his quality of life.”

According to Parekh, “Avoiding simple sugars is … the most important part of dietary modification in short bowel syndrome.” Simple sugars increase osmolar load to the GI tract, which can cause secretory diarrhea.

Intraluminal nutrients stimulate neural activity and blood flow, as well as pancreatic and biliary secretions, which may all play a part in growth of mucosal cells.8 Matarese recommends that if the colon is absent, the diet should include 40% to 50% of calories from [complex] carbohydrate, 20% to 30% from protein, and 30% to 40% from fat. If the colon is in continuity, the diet should be higher in complex carbohydrate and contain approximately 20% to 30% of calories as fat. The lower fat diet is useful for patients who have a colon, and especially those who have had significant ileal resection, because malabsorbed fat causes steatorrhea and further fluid losses. Higher carbohydrate diets are better for patients who have a colon, as carbohydrate will be converted to short-chain fatty acids by colonic bacterial fermentation and utilized for energy. Lactose restriction is not necessary unless the patient is lactose intolerant—some lactose-containing foods are important sources of vitamin D and calcium.4,5

Parrish recommends that food intake be divided into several small meals each day, and foods should be well-chewed. Slow infusion of an isotonic or near-isotonic enteral tube feeding can be used to supplement food intake, starting in the most proximal location possible to maximize absorptive surface area.5 For example, if a patient’s stomach and duodenum are functional, don’t place a jejunal feeding tube.

For patients with SBS who have a colon, foods containing oxalates may need to be restricted to prevent the formation of oxalate kidney stones. High-oxalate foods include dark green and other vegetables, nuts, beans, rhubarb, cocoa, chocolate, and black tea. Oxalate is normally bound to calcium, which restricts its absorption. Undigested fat can bind calcium, resulting in more oxalate from foods being absorbed from the colon, which then increases the amount of oxalate that passes through the kidneys. Calcium supplements and limitation of dietary fat can also be helpful to reduce the risk of oxalate renal stones.4,5

Both Matarese and Parekh recommend fiber supplementation for patients with SBS. Colonic bacteria can digest fiber to short-chain fatty acids, which are then absorbed by the colonic mucosa and used as an energy substrate. For patients without a colon, soluble fiber can be beneficial to thicken the ostomy effluent and prolong transit time.4

Oral Rehydration Solutions
“Fluid and electrolyte management is the most difficult aspect of the care of these patients,” says Matarese. Oral rehydration solutions (ORS) are very dilute glucose in water mixtures that contain sodium (Na) and potassium. The use of ORS is very helpful, especially in patients with a high output stoma. The specific ratio of water, glucose, and Na in ORS maximize intestinal absorption utilizing the glucose-Na coupled transport mechanism.9

Matarese recommends a solution that contains 70 to 90 milliequivalents of Na and 20 grams of carbohydrate per liter, as this has been shown to result in positive Na and fluid balance. There are many ORS products available, and solutions can also be made with simple household ingredients. Parekh prefers the World Health Organization (WHO) formula (Jianas Brothers, Kansas City, Mo.). To maximize the benefit of ORS, patients should replace both hypertonic (juices, soft drinks) and hypotonic (water) beverages with ORS as much as possible.

Vitamins and Minerals
Patients with SBS are at risk for vitamin and mineral deficiencies, so levels should be checked periodically. Patients with Crohn’s disease are at high risk for osteopenia and osteoporosis because of chronic steroid use; thus, calcium and vitamin D are particularly important. Patients with SBS are also at risk for low magnesium (Mg) levels. Magnesium lactate or gluconate are recommended because other forms of Mg can worsen diarrhea.4 Zinc should be supplemented when ostomy losses are high.7 Parrish recommends liberal use of salt and salty foods for patients with an end jejunostomy or ileostomy, as losses of Na range from 90 to 140 milliequivalents per liter.5

The ileum reabsorbs bile salts for normal digestion of fat and is also the major site for vitamin B12 absorption. Patients who have lost a significant portion of ileum are at risk for deficiency of fat-soluble vitamins and vitamin B12 .2 Vitamin B12 can be supplemented as monthly injections. To help maximize absorption, oral vitamin and mineral supplements should be in liquid or chewable form, as pills may pass through the GI tract undissolved.2,4

Glutamine, Growth Hormone, and Glucagon-like Peptide-2
Glutamine (Gln) is an amino acid that has been studied for its role in improvement of intestinal function and a fuel for mucosal cells.8 Growth hormone, normally secreted from the pituitary gland when nutrients are present in the intestine, is involved in intestinal mucosal hyperplasia and improvement in nutrient absorption. Administration of growth hormone has been found to improve intestinal adaptation in animal models and clinical investigations in humans, using recombinant human growth hormone (r-hGH).10 Glucagon-like peptide 2 (GLP-2) may also improve nutrient absorption but is not yet commercially available.8

The use of Gln, r-hGH, and GLP-2 in enhancement of bowel adaptation is controversial. Clinical trials of r-hGH and Gln are limited in number and results have been inconsistent.8,11 Among published reports, there are many differences in study protocols, dosage and administration, GI anatomy and disease state of study subjects, and outcome parameters.11 GLP-2 has been studied to a very limited extent in humans. The biologic mechanism of action of these factors alone or in combination is still unclear, and more study is needed to determine their safety and efficacy in SBS treatment.8

The FDA approved the use of r-hGH in SBS treatment in December 2003.8 The intestinal rehabilitation teams in Pittsburgh and at the Cleveland Clinic have used r-hGH (Zorbtive by Serono, Inc.) for some patients who have not responded to more conventional medication and dietary therapies. Matarese says, “Growth hormone can be useful in the right patients, decreasing or eliminating the need for PN.” She explains that r-hGH is administered in conjunction with 30 grams of oral Gln in divided doses, daily. Both intestinal rehab teams are part of a multinational trial testing an analogue of GLP-2, called Teduglutide (NPS Allelix), administered subcutaneously for some of their patients in the context of this research protocol.12

Matarese describes a challenging case: A 62-year-old gentleman was referred for evaluation for possible small bowel transplant. His history included atherosclerosis of the superior mesenteric artery with near-total occlusion and the development of collaterals. After surgery for small bowel resection, he had only 45 centimeters of jejunum and 15 centimeters of ileum, with an intact ileocecal valve and colon. At the time of evaluation, he was PN-dependent and had diarrhea after eating.

The patient was discharged for three months on PN to reduce anastomotic swelling and diarrhea was controlled with Imodium and tincture of opium. During this time, he was stabilized on a diet low in fat and simple sugars in six small feedings per day. The goal was for weight gain and improvement in nutritional status. “After three months, when we were unable to wean the TPN, we began Zorbtive 0.1 milligram per kilogram per day subcutaneously for 28 days plus 5 grams of oral glutamine six times per day. The diet was continued. Over the four-week course of growth hormone, we gradually reduced the PN until he required it only two nights per week.”

Intestinal Rehabilitation Programs
With the use of diet, medication, and growth factors, the intestinal rehab team in Cleveland can wean roughly 25% of their patients with SBS off of PN and intravenous fluid within one year after bowel resection. Approximately 50% of their patients with SBS are off of PN/IVF within two years, and 70% within 2.5 years.

Matarese started the intestinal rehabilitation program in Cleveland in 2001 and later joined the intestinal rehab and transplantation team at the University of Pittsburgh Medical Center in 2005. She states that 100% of their patients with SBS achieve full nutritional autonomy either through intestinal rehabilitation or transplantation. “This whole area of intestinal rehabilitation and intestinal transplantation is still very new and there is so much more to learn. So I would encourage dietitians who have an interest in this area to pursue this as a career path.”

— Theresa A. Fessler, MS, RD, CNSD, is a nutrition support specialist at the University of Virginia Health System in Charlottesville, Va., and a freelance writer.

1. Kelly D, Nehra V. Gastrointestinal Disease. In: Gottschlich MM, Fuhrman MP, Hammond KA, et al, eds. The Science of Practice of Nutrition Support: A Core Based Curriculum. Dubuque, Iowa: Kendall Hunt; 2001:521-523.

2. Jeejeebhoy KN. The etiology and mechanism of intestinal failure. In: Matarese LE, Steiger E, Seidner DL, eds. Intestinal Failure and Rehabilitation, A Clinical Guide. Boca Raton, Fla.: CRC Press; 2005:25-37.

3. American Society for Parenteral and Enteral Nutrition Board of Directors and the Clinical Guidelines Task Force. Guidelines for the use of parenteral and enteral nutrition in adult and pediatric patients. J Parenteral Enteral Nutr. 2002;26(1 Suppl): 1SA-138SA.

4. Matarese LE, O’Keefe SJD, Kandil HM, et al. Short bowel syndrome: Clinical guidelines for nutrition management. Nutr Clin Pract. 2005;20(5):493-502.

5. Parrish CR. The Clinician’s Guide to Short Bowel Syndrome. Pract Gastroenterol. 2005;XXIX(9):67-106.

6. Kandil HM, O’Keefe SJD. Medications: Andidiarrheals, H2 Blockers, Proton Pump Inhibitors, and Antisecretory Therapy. In: Matarese LE, Steiger E, Seidner DL, eds. Intestinal Failure and Rehabilitation, A Clinical Guide. Boca Raton, Fla.: CRC Press; 2005:149-159.

7. Fessler T. Trace element monitoring and therapy for adult patients receiving long-term total parenteral nutrition. Pract Gastroenterol. 2005;XXIX(3):44-65.

8. Ziegler TR, Tian J, Washizawa N, et al. Use of trophic substances in the treatment of intestinal failure. In: Matarese LE, Steiger E, Seidner DL, eds. Intestinal Failure and Rehabilitation, A Clinical Guide. Boca Raton, Fla.: CRC Press; 2005:187-207.

9. Kelly DG, Nadeau J. Oral rehydration solution: A low tech, oft neglected therapy. Pract Gastroenterol. 2004;XXVIII(10):51-62.

10. Parekh NR, Steiger E. Criteria for the use of recombinant human growth hormone in short bowel syndrome. Nutr Clin Pract. 2005;20(5):503-508.

11. Matarese LE, Seidner DL, Steiger. Growth hormone, glutamine, and modified diet for intestinal adaptation. J Am Diet Assoc. 2004;104(8):1265-1272.


Information on oxalate content of foods:

• Pennington JAT, Douglass JS. Bowes & Church’s Food Values of Portions Commonly Used. Baltimore: Lippincott Williams & Wilkins; 2005:351.

University of Pittsburgh Medical Center


Information on oral rehydration solutions:

• Table 20: Commercial and “Pseudo” Oral Rehydration Solutions. In: Parrish CR. The Clinician’s Guide to Short Bowel Syndrome. Pract Gastroenterol. 2005;XXIX(9):67-106. Available at: http://www.uvadigestivehealth.org (Scroll to “GI Nutrition,” click link, then scroll down to “Nutrition Articles in Practical Gastroenterology” in the right column.)

• Cera Products, www.ceralyte.com

• World Health Organization, www.who.int

Information on short bowel syndrome:

• Matarese LE, Steiger E, Seidner DL, eds. Intestinal Failure and Rehabilitation. A Clinical Guide. Boca Raton, Fla.: CRC Press; 2005.

• Nightingale JMD, ed. Intestinal Failure. London: Greenwich Medical Media; 2001.

• Parrish CR. The Clinician’s Guide to Short Bowel Syndrome. Pract Gastroenterol. 2005;XXIX: 67-106. Available at: http://www.uvadigestivehealth.org (Scroll to “GI Nutrition,” click link, then scroll down to “Nutrition Articles in Practical Gastroenterology” in the right column.)