Nutrition and the Sleeve Gastrectomy Patient: From Micronutrients to Dietary Patterns

| June 7, 2011 | 1 Comment

by Jacqueline Jacques, ND, and Liz Goldenberg, MPH, RD, CDN

Jacqueline Jacques is Chief Science Officer for Bariatric Advantage, and Liz Goldenberg is from New-York Presbyterian Hospital, Weill Cornell College of Medicine of Cornell University, Department of Surgery, New York, New York

Bariatric Times. 2011;8(6):12–15financial disclosure: Dr. Jacques and Ms. Goldenberg report no conflicts of interest relevant to the content of this article.

This article presents two perspectives on the latest data available regarding the nutritional needs of sleeve gastrectomy patients. Part 1 reviews the available data on the micronutrient status of these patients, including data on B12, folate, iron, and other nutrients, as well as discusses possible causes of deficiency in this patient population. Part 2 reviews the available data on eating patterns, food tolerance, and food intake in sleeve gastrectomy patients, and also provides examples of food intake progression currently recommended for these patients.

Part 1: Micronutrient Levels and Sleeve Gastrectomy
by Jacqueline Jacques, ND

Introduction. There are very limited data available on the impact of the vertical sleeve gastrectomy (SG) on micronutrient status. Most of the published data on this procedure have focused on surgical safety and outcomes, and, thus, the growing but limited body of intermediate range follow up has little to say regarding nutrition. This section discusses a handful of short-term, follow-up articles on the subject. Most literature refers to SG as a purely restrictive procedure (since it is limited to surgical alteration of the stomach), which may give the impression that there should be minimal impact on vitamin and mineral absorption. However, the position statement from the American Society of Metabolic and Bariatric Surgery (ASMBS) notes that, “The mechanisms of weight loss and improvement in comorbidities seen after SG might be related to gastric resection, neurohormonal changes related to gastric restriction or gastric emptying, or some other unidentified factor or factors.”[1] Because vitamin and mineral status can be adversely impacted in the absence of malabsorption, it is not surprising that even the limited available data begin to indicate some challenges.

B12, folate, and iron. Perhaps in an effort to compare against Roux-en-Y gastric bypass (RYGB), we have early data that predominantly focus on vitamin B12, folic acid, and iron. Hakeam et al2 followed 61 SG patients for one year. Patients were not taking vitamins. Over the course of the study, 4.9 percent of the patients developed iron-deficiency anemia, 18.1 percent of patients developed new B12 deficiency (8.1% had B12 deficiency before surgery, 26.2% at the end of one year), and 9.8 percent of patients developed new onset folate deficiency. Toh et al3 compared pre-operative data to one-year data in 11 SG patients and found that 15 percent had low hemoglobin and 25 percent had elevated homocysteine at the conclusion of 12 months. Aarts et al[4] studied 60 SG patients for one year. Patients were instructed to take a multivitamin with 150 percent of the recommended dietary allowance (RDA) three times daily (exact contents unknown). At the end of one year, 26 percent of patients had anemia, 43 percent had iron deficiency, 15 percent had folic acid deficiency, and nine percent had B12 deficiency. Finally, Gerher et al[5] provided three-year data in 50 SG patients. Patients in this study were all instructed to take a standardized multivitamin daily (Table 1). At the end of the study, 18 percent of patients had iron deficiency, 18 percent had B12 deficiency, and 22 percent had folate deficiency.

Other nutrients. Available data on other nutrients are minimal. Toh et al[3] found vitamin D deficiency in 43 percent of SG patients at one year. Aarts et al[4] found vitamin D deficiency in 39 percent of study participants and low albumin in 15 percent. The same study also found elevated levels of vitamin A, B1, and B6. The authors suggested that these elevations were most likely due to supplementation, but since the contents of the product being taken was not disclosed, the levels and forms of these nutrients that created these results are unknown. Gehrer et al[5] found low levels of zinc, vitamin D, and albumin at three years. There is also a single published case report6 of an acute thiamine (B1) deficiency (Wernicke’s encephalopathy) in a patient with vomiting due to stricture.

Possible causes of deficiency. As with all other bariatric surgical procedures, the causes of deficient micronutrients after SG are likely multifold. Pre-operative deficiency is common in individuals who have obesity and morbid obesity[6,7] and several of the studies cited in this article have shown that patients preparing for SG are no different.[3–5] People eat less food after a SG due to the restrictive nature of the procedure. This likely accounts for some portion of the weight loss, but will naturally result in a greater challenge in meeting nutritional needs. Whether by instruction (e.g., “eat more protein and less carbohydrate”) or due to issues such as food intolerance, most bariatric surgery patients eat differently after surgery. This can change the nutrient levels in the diet and result in imbalances. For example, we have already seen evidence for much folate deficiency after SG. One possible cause of this might be the elimination of folate-fortified foods from the daily diet. Foods fortified in the United States include those made with refined flour and grains, such as bread, pasta, and breakfast cereals. New anatomy is a likely contributor to folate defiency after SG. Vitamin B12, for example, requires R protein and intrinsic factor (IF) from the stomach for optimal absorption. For this reason, removal of a large portion of stomach tissue most certainly contributes to the substantial rates of B12 deficiency already being revealed in early data. Iron deficiencies might arise from reduced intake of iron-rich foods, rapid transit of food through the duodenum, or other causes, such as chronic use of proton pump inhibitors (PPIs).[9]

Given the anatomy of the SG and our knowledge of other procedures, we might predict some additional possible challenges. Copper deficiency is something to be aware of as a portion of copper absorption occurs in the stomach. More cases of thiamine deficiency are likely as they appear with all bariatric surgeries, and we have evidence of pre-operative deficiency.[10] Bone loss is a question that may take time to answer. We do have evidence for bone loss with nonsurgical weight loss and all other common forms of surgical weight loss, so sleeve cannot be assumed to be immune.

Many questions remain—What to do now? Clearly, before substantiated nutrition recommendations can be made for SG, much more data are needed. The early data, however, certainly suggest that deficiencies are not likely to be rare, thus clinicians should be providing guidance for both preventive nutrition and laboratory monitoring as is done with other procedures. As a starting point, in 2008 the American Association of Clinical Endocrinologists (AACE), The Obesity Society (TOS), and the ASMBS issued a joint guideline paper[11] providing a general recommendation for routine nutrition that is not procedure specific. In 2010, The Journal of Clinical Endocrinology and Metabolism published an article by the Endocrine Society12 addressing postoperative management of bariatric surgery patients. This article provides a good general schedule for laboratory tests and frequency.

Conclusions. Because SG is still a “newcomer” as a primary procedure, we have much to learn about the nutritional impact of this procedure. Programs offering this procedure should establish protocols for prevention and monitoring, and adjust their strategies as needed on a per-patient basis. In due time, research should allow for the establishment of specific professional guidelines for SG as we have seen with other bariatric surgeries.

PART 2: eating patterns, food tolerance, and food intake in sleeve gastrectomy patients
by Liz Goldenberg, MPH, RD, CDN

Introduction. SG, being a relatively new surgical option for treatment of morbid obesity, has been studied only minimally. In 2003, Johnston et al[13] published one- and three-year data on “a simpler, more physiological type of gastroplasty that would dispense with implanted foreign material, such as bands and reservoirs,” called the Magenstrasse and Mill operation. This operation has become what we know today as vertical SG. The procedure is distinct in the following ways:
1.     It permanently removes a large portion (approximately 80%) of the hormone-secreting stomach, which renders it irreversible unlike both RYGB and adjustable gastric banding (AGB).
2.    It leaves the pylorus intact and in touch with ingested food unlike RYGB.
3.    It creates a uniquely-shaped narrow pathway along the lesser curve of the stomach for food to travel.

How SG works. Initially, it was widely believed that the restrictive nature of the SG, which leaves only a small stomach remnant, was responsible for weight loss by causing reduced portion sizes. Furthermore, echographic studies of gastric emptying show that the more the stomach antrum is distended, the less the feeling of hunger.[14] It is now understood that there is much more to this operation. Changes in both gastrointestinal hormones and motility lead to the “food-limiting” effects of sleeve gastrectomy.15 Several studies[14,15,17,26] teach us that removal of the gastric fundus brings about a decrease in ghrelin, and an increase in both glucagon-like peptide-1 (GLP-1)and peptide-YY (PYY). The majority of evidence points to these changes in gut peptides causing a quickening of meal transit time and an increase in both satiety and duration of satiation.

In response to studies that fail to show more rapid gastric emptying, Gagner[29] argues that these results may be influenced by the size of the bougie used to create the sleeve or by the length of the antrum that is remaining.

If there is, indeed more rapid gastric emptying, there is quicker feedback from ingested food reaching the distal small bowel. This is known as the “ileal brake” and is part of the hindgut hypothesis.[16–18] Additionally, the incretin hormones PYY, GLP-1, and gastric inhibitory polypeptide act in the central nervous system, especially the hypothalamus and brain stem, to reduce food intake.[17]

Eating patterns and body weight regulation. Two rat studies expose mechanisms besides food restriction that help to achieve weight loss after SG. In the first study by Valentí et al,[19] rats given a high-fat chow diet continued to lose weight even though they consumed significantly more calories than those fed a normal chow diet. The authors found that rats fed the high-fat chow “defended” their weight with a lower food efficiency rate, meaning they were less adept as compared to sham-operated rats at converting the food they consumed into energy. A second study by Stefater et al[20] found that rats that underwent SG had a short period of anorexia postoperatively, followed by persistent loss of fat mass. These rats spent more total time eating over the course of the day but ate smaller, more frequent meals than nonoperated animals. The authors could not point to either altered energy expenditure or intestinal malabsorption as plausible explanations for the surgery’s dramatic effects. Even after operated rats were starved and then re-fed, they were not hyperphagic. These rats did not regain the lost weight following the initial anorectic period as one would expect to see following caloric restriction. The authors concluded that SG does not impair an animal’s ability to overeat (restriction), but instead somehow suppresses the animal’s drive to overeat.

In contrast to rats, it is unclear if humans who have SG eat more frequently. A study by Melissas et al[15] of 14 patients showed split results. One half of patients ate 2 to 3 meals daily prior to surgery. This group did increase their meal frequency postoperatively to 5 to 6 meals daily. However, the other half of the group, which ate more than eight times per day preoperatively, actually reduced their number to 2 to 3 meals daily. This trend held true for up to two years postoperatively. More human studies that look at changes in meal frequency will help us to better understand this phenomena.

Food tolerance. There are a few studies[14,15,21] that report on issues of overall food tolerance after SG. While there is a significant incidence of nausea and vomiting, and also of gastroesophageal reflux (although this may be independent of food intake) following SG, there may be improvement or even resolution of these symptoms over time.[14] This is most likely a result of patients adapting the meal size and eating speed to the limitations of the sleeve.[15] See sidebar “13 Practical Strategies for Slowing-Down Eating” for ways to teach patients to improve postoperative food tolerance. Patients can also practice these strategies prior to undergoing surgery.

More recent studies report more specifically on food tolerance. D’Hondt et al22 found the overwhelming majority of patients, 95.2 percent, who were surveyed following SG described their food tolerance to be acceptable to excellent. Only 4.8 percent reported poor-to-very poor satisfaction. When asked about the ability to eat red meat, white meat, vegetables, salad, bread, pasta, rice, and fish, patients responding to a questionnaire listed pasta and red meat as foods that had the highest ratings of difficulty. In this study, fish and vegetables ranked the lowest and were highly tolerable. In another, larger study of 540 Spanish SG patients by Sánchez-Santos et al,[23] patients also rated beef as the most difficult food to tolerate. Alternatively, when comparing four different types of surgeries in an Israeli population, Schweiger et al[24] found that beef was not noted to be significantly problematic. Instead, salad, vegetables, bread, and pasta reflected the lowest tolerance scores for the SG patients. Study participants who had undergone LAGB, RYGB, or biliopancreatic diversion with duodenal switch (BPD-DS) fared better with these particular foods at 3 to 6 months postoperatively. Schweiger et al[24] noted that only the results for vegetables were statistically significant at this 3 to 6 month time interval. At 6 to 12 months postoperatively, all four of the surgeries seemed to create difficulties eating bread. Overall, when specifically comparing eating ability satisfaction, LAGB had significantly poorer scores than did SG.[24]

Kafri et al,[25] another Israeli research group, also looked at food tolerance after SG. By self-report, patients who were one year or more postoperative had higher food tolerance scores than those who were less than one year postoperative. Kafri et al also found an increased consumption of “unhealthy foods,” such as sugary/fatty/soft, high-calorie foods; chocolate pudding, soft drinks, cookies, and cakes were among those queried in the group of patients who were more than one year post SG. This finding is similar to what is seen after other weight loss procedures; adherence to healthy behaviors diminishs with time.[25]

Hunger and cravings. Hunger and appetite are commonly reduced after SG.[14,15,26] Himpens compared hunger levels of SG and LAGB patients. Appetite was suppressed more often in SG patients, than in LAGB patients, both one and three years after surgery. After three years, over 45 percent of patients who underwent SG but less than three percent of patients who underwent LAGB reported abolished or diminished hunger. There may also be less sweets cravings after SG versus after LAGB, but the numbers did not reach statistical significance at three years; 2.9 percent of patients after LAGB versus 23 percent of patients after SG lost these cravings.[14]

Diet progression. There are limited studies specific to nutritional care of SG patients. Dietary recommendations thus far have been adapted from experiences with other bariatric surgeries and results of patient questionnaires.[14,22,24,25,27,28] Based on the information gathered from this research, the diet progression for the first month after SG may be as follows: liquids and protein shakes immediately postoperatively, followed by the addition of high-protein soft/pureed/ground foods, then high-protein soft solids, and lastly, the gradual addition of denser, whole foods. It would be wise to add the following foods back into the diet more cautiously: beef, vegetables/salad, bread, and pasta.

The following additional foods may be difficult to eat and thus more suitable for delayed introduction in the diet (i.e., approximately 6 weeks postoperatively): rice, grilled meats, and turkey/chicken breast. Toasted bread products, crackers, beans/lentils, tofu, ground meats, dark meat poultry, and cooked fruits/vegetables without tough peels may be more easily introduced between 3 and 4 weeks postoperatively.

See sample food ideas shared by Snyder-Marlow et al in Table 2.

Conclusion. More nutrition studies will help bariatric surgery professionals to better guide their patients after SG. If practitioners educate patients thoroughly on what to expect after surgery and how to create balanced menus of foods that are well tolerated, their confidence level and, hopefully, their likelihood of having safe and successful weight loss will increase.

1.)   Clinical Issues Committee of the American Society for Metabolic and Bariatric Surgery Updated position statement on sleeve gastrectomy as a bariatric procedure. Surg Obes Relat Dis. 2010;6(1):1–5. Epub 2009 Nov 17.
2)    Hakeam HA, O’Regan PJ, Salem AM, et al. Impact of laparoscopic sleeve gastrectomy on iron indices: 1 year follow-up. Obes Surg. 2009;19(11):1491–1496. Epub 2009 Jul 15.
3)    Toh SY, Zarshenas N, Jorgensen J. Prevalence of nutrient deficiencies in bariatric patients. Nutrition. 2009;25(11-12):1150–1156. Epub 2009 May 31.
4)    Aarts EO, Janssen IM, Berends FJ. The gastric sleeve: losing weight as fast as micronutrients? Obes Surg. 2011;21(2):207–211.
5)    Gehrer S, Kern B, Peters T, et al. Fewer nutrient deficiencies after laparoscopic sleeve gastrectomy (LSG) than after laparoscopic Roux-Y-gastric bypass (LRYGB)—a prospective study. Obes Surg. 2010;20(4):447–453. Epub 2010 Jan 26.
6)    Makarewicz W, Kaska L, Kobiela J, et al. Wernicke’s Syndrome after sleeve gastrectomy. Obes Surg. 2007;17(5):704–706.
7)    Kimmons JE, Blanck HM, Tohill BC, et al. Associations between body mass index (BMI) and the prevalence of low micronutrient levels among US adults. MedGenMed. 2006;8(4):59.
8)    Kaidar-Person O, Rosenthal RJ. Malnutrition in morbidly obese patients: fact or fiction? Minerva Chir. 2009;64(3):297–302. Review.
9)    Sarzynski E, Puttarajappa C, Xie Y, et al. Association between proton pump inhibitor use and anemia: a retrospective cohort study. Dig Dis Sci. 2011 Feb 12. [Epub ahead of print]
10)    Flancbaum L, Belsley S, Drake V, et al. Preoperative nutritional status of patients undergoing Roux-en-Y gastric bypass for morbid obesity. J Gastrointest Surg. 2006;10(7):1033–1037.
11)    Mechanick JI, Kushner RF, Sugerman HJ, et al; American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic and Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient. Obesity (Silver Spring). 2009;17 Suppl 1:S1–70, v.
12)    Heber D, Greenway FL, Kaplan LM, et al; Endocrine Society. Endocrine and nutritional management of the post-bariatric surgery patient: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2010;95(11):4823–4843.
13.    Johnston D, Dachtler J, Sue-Ling HM, et al. The Magenstrasse and Mill operation for morbid obesity. Obes Surg. 2003;13(1):10–16.
14.    Himpens. A prospective randomized study between laparoscopic gastric banding and laparoscopic isolated sleeve gastrectomy: results after 1 and 3 years. Obes Surg. 2006;16(11): 1450–1456.
15.    Melissas J, Daskalakis M, Koukouraki S, et al. Sleeve gastrectomy-a “food limiting” operation. Obes Surg. 2008;18(10):1251–1256. Epub 2008 Jul 29.
16.    Shah S, Shah P, Todkar J, et al. Prospective controlled study of effect of laparoscopic sleeve gastrectomy on small bowel transit time and gastric emptying half-time in morbidly obese patients with type 2 diabetes mellitus. Surg Obes Relat Dis. 2010;6(2):152–157. Epub 2009 Dec 22.
17.    Kohli R, Stefater MA, Inge TH. Molecular insights from bariatric surgery. Rev Endocr Metab Disord. 2011 Feb 18. [Epub ahead of print]
18.    Braghetto I, Davanzo C, Korn O, et al. Scintigraphic evaluation of gastric emptying in obese patients submitted to sleeve gastrectomy compared to normal subjects. Obes Surg. 2009;19(11):1515–1521. Epub 2009 Aug 28.
19.    Valentí V, Martín M, Ramírez B, et al. Sleeve gastrectomy induces weight loss in diet-induced obese rats even if high-fat feeding is continued. Obes Surg. 2010 Sep 12. [Epub ahead of print]
20.    Stefater MA, Pérez–Tilve D, Chambers AP, et al. Sleeve gastrectomy induces loss of weight and fat mass in obese rats, but does not affect leptin sensitivity. Gastroenterology. 2010;138(7):2426–2436, 2436.e1–3. Epub 2010 Mar 10.
21.    Keidar A, Appelbaum L, Schweiger C, et al. Dilated upper sleeve can be associated with severe postoperative gastroesophageal dysmotility and reflux. Obes Surg. 2010;20(2):140–147. Epub 2009 Dec 1.
22.    D’Hondt M, Vanneste S, Pottel H, et al. Laparoscopic sleeve gastrectomy as a single-stage procedure for the treatment of morbid obesity and the resulting quality of life, resolution of comorbidities, food tolerance, and 6-year weight loss. Surg Endosc. 2011 Feb 27. [Epub ahead of print]
23.    Sánchez-Santos R, Masdevall C, Baltasar C, et al. Short- and mid-term outcomes of sleeve gastrectomy for morbid obesity: the experience of the Spanish National Registry. Obes Surg. 2009;19:1203–1210.
24.    Schweiger, C, Weiss, R, Keidar A. Effect of different bariatric operations on food tolerance and quality of eating. Obes Surg. 2010;20:1393–1399.
25.    Kafri N, Valfer R, Nativ O, Shiloni E, Hazzan D. Health behavior, food tolerance, and satisfaction after laparoscopic sleeve gastrectomy. Surg Obes Relat Dis. 2011 Jan-Feb;7(1):82-8. Epub 2010 Oct 31.
26.    Karamanakos SN, Vagenas K, Kalfarentzos F, Alexandrides TK. Weight loss, appetite suppression, and changes in fasting and postprandial ghrelin and peptide-YY levels after Roux-en-Y gastric bypass and sleeve gastrectomy: a prospective, double blind study. Ann Surg. 2008;247(3):401–407.
27.    Snyder-Marlow G, Taylor D, Lenhard MJ. Nutrition care for patients undergoing laparoscopic sleeve gastrectomy for weight loss. J Am Diet Assoc. 2010;110(4):600–607.
28.    Aills L, Blankenship J, Buffington C, et al; Allied Health Sciences Section Ad Hoc Nutrition Committee. ASMBS allied health nutritional guidelines for the surgical weight loss patient. Surg Obes Relat Dis. 2008;4(5 Suppl):S73–108. Epub 2008 May 19.
29.    Gagner M. Faster gastric emptying after laparoscopic sleeve gastrectomy. Obes Surg. 2010;20(7):964–965; author reply 966–967.

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