Bariatric Times

JUN 2017

A peer-reviewed, evidence-based journal that promotes clinical development and metabolic insights in total bariatric patient care for the healthcare professional

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14 Nutritional Considerations in the Bariatric Patient Bariatric Times • June 2017 INTRODUCTION Bariatric surgery is the most effective treatment for obesity. 1 However, as with many chronic disease treatments, it can come with side effects. The most popular bariatric surgeries performed in the United States are Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), both of which alter the upper gastrointestinal tract anatomy. Less common operations include the adjustable gastric band (AGB) and the biliopancreatic diversion with duodenal switch (BPD-DS), the former being the only surgery that does not permanently alter anatomy. 2 Any surgery that impacts the gastrointestinal tract anatomy could be expected to have nutrition-related side effects. Many of these can be managed through diet intervention, but sometimes medical and surgical intervention is necessary. Clinicians must be prepared to manage the challenges faced by their patients, and it is important to begin with an understanding of the pathophysiology of the complication. This article provides an overview of the pathophysiology of several nutrition- related side effects of bariatric surgery along with strategies for prevention and management. While micronutrient deficiencies are a significant consideration following bariatric surgery, they will not be addressed in this article. NAUSEA/VOMITING Causes. Nausea and vomiting are the most common complaints after bariatric surgery. 3 One study with self- reported data indicated that 68.6% of RYGB and 65.1% of AGB patients had an episode of vomiting in the first six postoperative months. 4 Reports of nausea and vomiting should prompt the clinician to inquire about eating behaviors. 3,5 Sarwer et al reported that additional postoperative counseling by a dietitian resulted in fewer incidences of nausea and vomiting four months after surgery, suggesting that eating behaviors were contributing factors. 6 This could entail not chewing thoroughly or eating too quickly as well as progressing to challenging food textures prematurely. The presence of nausea may also indicate dehydration, which is a common complication in the early postoperative period. 5,7 Other common causes of nausea include lactose intolerance and displeasure with vitamin and mineral supplements. Management. Taking smaller bites of food or sips of fluid, chewing food thoroughly, and slowing the pace of eating can often alleviate nausea and vomiting. 3,8 In some cases, a patient may need to avoid a poorly tolerated food until a later date. 5 In the presence of nausea and vomiting, a clinician should assess the patient's hydration status. If a dehydrated patient is unable to rehydrate on their own, intravenous fluid would be indicated for repletion. In the case of persistent vomiting, thiamin will need to be repleted. 9 If nausea and vomiting cannot be traced to a diet factor, or if the nausea is a ssociated with epigastric pain, a clinician should be alerted to the potential for an acute surgical complication requiring further evaluation. 3 DIARRHEA Causes. Diarrhea is caused by a nutrient moving through the digestive tract without being fully digested. In the context of bariatric surgery, this may be food that was not chewed properly or was hastened through the digestive tract with the use of liquid. 1 0 Other substances that may not be digested properly are lactose and sugar alcohols. Since lactose is digested in the small intestine, one might expect that patients with RYGB and BPD-DS would be more likely to suffer from lactose intolerance following surgery than patients with SG or AGB; however, lactose intolerance has been reported anecdotally after all types of bariatric surgeries. Sugar alcohols, such as malitol, sorbitol, and xylitol, are not digested in the small intestine but are fermented in the large intestine and can have a laxative effect in some people. 1 1 They are often found as a sugar substitute in micronutrient supplements and protein bars. Diarrhea is a symptom of dumping syndrome, which will be discussed later in this article. Some medications have been implicated in the cause of diarrhea; one that is occasionally used in bariatric patients is ursodiol (Actigall), which treats and prevents the formation of gallstones. Additionally, small intestine bacterial overgrowth (SIBO), which can cause diarrhea, can occur after RYGB in one of the intestinal limbs. 12 Management. When troubleshooting reports of diarrhea, a clinician should first help the patient to differentiate between loose stools and diarrhea. Bowel movement inconsistency is common in the early weeks and months following surgery and will likely resolve on its own as the diet normalizes. There are two main types of RYGB: proximal (or short limb), which is considered the standard R YGB today, and distal (or long-limb), which decreases the length of the common channel and causes macronutrient malabsorption. Patients with a distal RYGB, whether as a primary surgery or as a revision, should expect frequent, loose bowel movements throughout the day as a result of the shortened intestinal tract. 1 3 If the patient is truly having diarrhea, a food log can be helpful to identify offending factors such as lactose or sugar alcohols, or eating behaviors such as poor chewing or liquids combined with solid foods. If SIBO is suspected, it can be diagnosed using a breath test and treated with antibiotics. 12 CONSTIPATION Causes. Constipation is a result of lack of intestinal motility and/or hard stools. Constipation may begin developing before surgery if the bariatric team is recommending a preoperative diet low in fiber. Some medications commonly prescribed after surgery, such as opioids and proton pump inhibitors, have been associated with constipation. Iron and calcium are two minerals that must be supplemented postoperatively. Iron, in the form of oral ferrous sulfate and ferrous gluconate, is associated with constipation. 14 While there is no evidence linking calcium supplementation to constipation, it has been seen anecdotally. Compounds in coffee, both caffeinated and decaffeinated, increase colonic motility; program requirements eliminating caffeinated beverages after surgery can increase risk of constipation. 15 Chronic dehydration can lead to constipation by hardening the stool. Lack of physical activity has been connected to constipation although the relationship is not totally understood. 11 Management. As with diarrhea, it is important for clinicians to help patients differentiate between constipation and the normal effects of surgery. The changes to the digestive tract and by LAURA ANDROMALOS, MS, RD, CD, CDE Bariatric Times. 2017;14(6):14–17. RD 911: Nutrition-Related Complications after Bariatric Surgery ABSTRACT T his article provides an overview of the pathophysiology of the following nutrition-related side effects of bariatric surgery: nausea/vomiting, diarrhea, constipation, g astroesophageal reflux disease, gout, dumping syndrome, reactive hypoglycemia, and kidney stones. The author discusses causes of these complications and reviews evidence- based strategies for their prevention and management. KEYWORDS nutrition, bariatric surgery, complications, nausea/vomiting, diarrhea, constipation, gastroesophageal reflux disease, gout, dumping syndrome, reactive hypoglycemia, kidney stones T his column is dedicated to providing evidence-based bites of information for the clinician on nutritional considerations in the bariatric patient.

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