Bariatric surgery the importance of nutrition 39 Bariatric surgery the importance of nutrition

bAriAtriC Surgery And the imPortAnCe of nutrition

mary o’kane Consultant dietitian (adult obesity), Leeds teaching Hospitals nHS trust

mary is a Consultant dietitian supporting patients with severe and complex obesity in the medical and surgical obesity pathways. member of bomSS council. member of niCe clinical guidelines obesity 2006 and 2014.

the prevalence of obesity in the uk continues to rise and is associated with many health issues such as diabetes, metabolic syndrome, obstructive sleep apnoea and osteoarthritis. the focus of treatment is on dietary, activity and lifestyle changes; however, for those with severe and complex obesity, bariatric surgery may be a treatment option.

The main bariatric surgical procedures are the gastric band, gastric bypass and sleeve gastrectomy (Figures 1-4). The duodenal switch is performed less frequently. All procedures affect the dietary intake and the gastric bypass, sleeve gastrectomy and duodenal switch affect absorption to varying degrees. For patients with severe and complex obesity, bariatric surgery is an additional tool which will aid weight loss and result in metabolic improvements. The National and Bariatric Surgery Registry (NBSR) reported that the average weight loss at one year after surgery was 58.4% excess weight (1). Two years after surgery, 65 percent of patients with Type 2 diabetes were able to stop their medication.

eLigibiLity for bariatriC Surgery To be eligible for bariatric surgery, a number of criteria must be met (National Institute for Health and Care Excellence (NICE) 2014 (Table 1) (2). In the NHS, patients are referred in for surgery by the Tier 3 medical obesity services. The patient will undergo a comprehensive multidisciplinary team (MDT) assessment which includes exploring the benefits and risks of surgery. The dietitian plays a key role in the assessment of the patient’s understanding of bariatric surgery and ability to comply with postoperative dietary advice and cope with the emotional impact. Not all patients will go forward for surgery as the team may consider some patients to be too high risk or recommend further investigation and treatment. Other patients will decide that surgery is not for them or that the timing is not appropriate.

impaCt on diet and nutrition All of the surgical procedures impact on dietary and nutritional intake (Table 2). The gastric bypass, sleeve gastrectomy and duodenal switch procedures affect the absorption of micro and macronutrients to varying degrees. The specialist bariatric dietitian plays an important role is supporting patients through their weight loss journeys and ensuring nutritional needs are met.

Following surgery, all patients are advised to progress their diet slowly, beginning with a liquid diet before moving onto blended food, soft food and then foods of a more normal texture. They must learn to chew their food well, eat slowly and avoid having drinks with meals. Certain textures of food are difficult to manage for example, roast or grilled meats and poultry, bread, rice and pasta. These can be replaced with casseroled meats and poultry, crisp breads, crackers and toasted bread and potatoes. The initial portion sizes are very small, but will increase over time. Patients need support to make the dietary changes including the planning of meals. Some patients may struggle to follow the advice. If they try foods of an inappropriate texture or do not chew their food, they may find it becomes lodged in the gastric pouch causing pain and discomfort. This may then lead to food avoidance /phobias or replacement with soft high calorie foods

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References: 1. Fell et al (2000) Aliment Pharmacol Ther 14 (3) : 281-9. 2. Afzal et al (2005) Dig Dis Sci 50 (8) : 1471-5. 3. Lionetti et al (2005) JPEN 29 (4 suppl): S173-5. 4. Bascietto et al (2004) J Pediatri Gastro Nutr 29 supplement 1: S106-S107. 5. Borrelli et al (2006) Clin Gatro Hepatol 4(6): 744-53. 6. Buchanan et al (2009) Aliment Pharmacol Ther 30:501-507. 7. Phylactos et al (2001) Act Paedi 90(8) : 883-8. 8. Rubio et al (2011)Aliment Pharmacol Ther 33: 1332-1339. 9. Gavin

and a diet of poor quality (3). Unfortunately, soft and crispy textured foods such as crisps, biscuits, cakes and ice cream are easy to consume.

In addition, the sleeve gastrectomy, gastric bypass and duodenal switch affect absorption. For all of these procedures, the absorption of calcium, vitamin D, vitamin B12, zinc, copper and selenium may be reduced (4, 5). The duodenal switch also impacts on the absorption of fat, protein and fat soluble vitamins and so carries additional risks. Consequently patients are advised to take additional multivitamin and mineral supplements.

nCepod The National Enquiry into Patient Outcome and Death 2012 report ‘Too Lean a Service’ reviewed the bariatric patient journey from referral to postsurgical follow up and made a number of recommendations (6). In the report’s foreword, Bertie Leigh, NCEPOD chairman, said, “If changes in eating behaviour are to be sustained, the advice of the dietitian will be invaluable. If surgery is to be sufficiently radical to resolve problems of extreme obesity in isolation, the dangers of malnutrition cannot be avoided with confidence.” Recommendations included access to good quality postoperative dietary advice and a continuous long-term follow up plan.

bomSS Survey A survey of current practice of British Obesity and Metabolic Surgery Society (BOMSS) members with respect to nutritional assessment and monitoring of patients undergoing bariatric surgery was undertaken in 2012 (7). This showed that whilst there were areas of good practice, there was also considerable variation. It highlighted variation in nutritional monitoring and the use of vitamin and mineral supplements. Although the American Association of Clinical Endocrinologists, The Obesity Society and American Society for Metabolic and Bariatric Surgery (AACE/ASMBS/TOS) had published guidance (Medical Guidelines for Clinical Practice for the peri-operative Nutritional, Metabolic and Non-surgical Support of the Bariatric Surgery Patient), many centres had found this difficult to implement (4). BOMSS council agreed that UK guidance was needed and a working group led by Mary O’Kane was formed. Its remit was to develop the first UK guidance on nutritional monitoring and supplementation for patients undergoing bariatric surgery.

bomSS guidanCe As part of the BOMSS survey, relevant literature, including other guidelines, was reviewed (7). The working group agreed the BOMSS guidance would cover pre-operative assessment, post-operative nutritional monitoring, abnormal results and clinical problems and vitamin and mineral supplementation. A further literature review was undertaken.

Writing the guidelines was a challenge. Whilst the AACE/ASMBS/TOS guidelines were comprehensive, they were difficult to apply in practice in the UK. There were significant differences in the recommendations around vitamin D in the US and usual practice in the UK. It was agreed that the BOMSS guidelines should be practical and easy to implement and address many of the clinical concerns.

Where there were no clear conclusions from the literature, consensus opinion was reached. Recommendations were made about pre-operative nutritional assessment, post-operative nutritional monitoring and frequency, vitamin and mineral supplements and clinical problems/abnormal blood results. The draft guidelines went out to wide consultation within BOMSS and there was healthy debate. In addition, the views of endocrinologists were sought, especially concerning vitamin D.

The final version ‘BOMSS Guidelines on perioperative and postoperative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery’ was launched in October 2014 and is available from the BOMSS website (8). A summary of vitamin and mineral supplementation is given in Table 3, but the guidelines contain the full recommendations on nutritional monitoring and supplementation.

gp guidanCe At the same time, a working group, led by Helen Parretti from The Royal College of General Practitioners, was writing guidelines for the management of bariatric surgery patients: ‘Ten top tips

The BOMSS nutritional guidelines have been well received by the bariatric surgery community, GPs and patients and have stimulated debate.

for the management of patients post-bariatric surgery in primary care’ (9). As part of this work, a shorter version of the BOMSS guidance was produced for GPs: ‘GP Guidance: Management of nutrition following bariatric surgery’ (10).

niCe CLiniCaL guideLineS 189 obeSity In the update of the NICE Clinical Guidelines 189 Obesity, the recommendations on longerterm nutritional follow up of bariatric patients were strengthened (2). There is lack of clarity however as to how this will be achieved.

feedbaCk and neXt StepS The BOMSS nutritional guidelines have been well received by the bariatric surgery community, GPs and patients and have stimulated debate. They are available on the BOMSS website.

The NHS England Obesity Clinical Reference Group is writing the service specification for the follow up of bariatric surgery patients. Mary O’Kane is chairing and leading this subgroup and the guidelines will play a key part of this work. Defining the components of the longer-term follow up of these patients is a challenge. Generally, the bariatric centres are only commissioned to provide two years follow up after the bariatric procedure with care returning to the GP. Although the bariatric centre has a responsibility to ensure that there is clear communication at the time of discharge around nutritional monitoring and vitamin and mineral supplementation, there is no robust mechanism for ensuring lifelong nutritional monitoring. This is stimulating active discussion in the subgroup as to how it is best addressed.

table 1: niCe criteria for bariatric surgery

Bariatric surgery is a treatment option for people with obesity if all of the following criteria are fulfilled:

• They have a BMI of 40kg/m2 or more, or between 35kg/m2 and 40kg/m2 and other significant disease (for example, type 2 diabetes or high blood pressure) that could be improved if they lost weight. • All appropriate non-surgical measures have been tried but the person has not achieved or maintained adequate, clinically beneficial weight loss. • The person has been receiving or will receive intensive management in a Tier 3 service.

• The person is generally fit for anaesthesia and surgery.

• The person commits to the need for long-term follow up.

Bariatric surgery for people with recent-onset type 2 diabetes:

• Offer an expedited assessment for bariatric surgery to people with a BMI of 35 or over who have recentonset type 2 diabetes [12] as long as they are also receiving or will receive assessment in a tier 3 service (or equivalent). • Consider an assessment for bariatric surgery for people with a BMI of 30-34.9 who have recent-onset type 2 diabetes, as long as they are also receiving or will receive assessment in a tier 3 service (or equivalent). • Consider an assessment for bariatric surgery for people of Asian family origin who have recent-onset type 2 diabetes at a lower bmi than other populations, as long as they are also receiving or will receive assessment in a tier 3 service (or equivalent).

table 2: impact of bariatric surgery on nutrition (summary)

Bariatric surgical procedure impact on nutrition

gastric band no impact on absorption; however an over tight gastric band affects nutritional intake and quality of diet Sleeve gastrectomy may be some impact on absorption especially iron and vitamin b12 gastric bypass impacts on absorption of iron, vitamin b12, calcium and vitamin d and may impact on trace elements

duodenal switch impacts on absorption of protein, fat, calcium, fat soluble vitamins and trace minerals

table 3: nutritional supplements and surgical procedure (summary)

Surgical procedure Vitamin and mineral supplements

gastric band, gastric bypass, sleeve gastrectomy, duodenal switch multivitamin and mineral supplement

gastric bypass, sleeve gastrectomy, duodenal switch iron, calcium, vitamin d, vitamin b12 duodenal switch additional fat soluble vitamins

all procedures Supplement with additional thiamine and vitamin b Co strong immediately if there is prolonged vomiting

ConCLuSion Bariatric surgery is an appropriate treatment option for some patients with severe and complex obesity, providing certain criteria are met. It can result in significant weight loss and resolution or improvement in comorbidities. If patients receive the correct advice and support and are compliant, there should be minimal risk of nutritional issues. Long-term nutritional monitoring and compliance with vitamin and mineral supplements are essential components of aftercare. The BOMSS guidelines give clear recommendations which support the care of these patients and may stimulate future research in this area.

references 1 Welbourn R, Small P, Finlay I, Sarela A, Somers S, Mahawar K et al. National Bariatric Surgery Registry: Second registry report 2014. ISBN 978-09568154-8-4. Oxfordshire: Dendrite Clinical Systems Ltd 2 National Institute for Health and Care Excellence (2014) NICE CG189. Obesity: identification, assessment and management of overweight and obesity in children, young people and adults [internet], London: National Institute for Health and Care Excellence. Available from www.nice.org.uk/guidance/cg189 3 Sarwer DB, Dilks RJ, West-Smith L. Dietary intake and eating behaviour after bariatric surgery: threats to weight loss maintenance and strategies for success. Surg Obes Relat Dis 2011; 7(5): 644-651 4 Mechanick JI, Kushner rF, Sugerman HJ, Gonzalez-campoy M, collazo-clavell ML, Guven S 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 peri-operative nutritional, metabolic and non-surgical support of the bariatric surgery patient. Endocrin Pract. 2008; 14(S1): 1-83 5 Mechanick JI, Youdim a, Jones Db, Garvey WT, Hurley DL, McMahon MM et al. clinical practice guidelines for the peri-operative nutritional, metabolic, and non-surgical support of the bariatric surgery patient - 2013 update: Co-sponsored by the American Association of Clinical Endocrinologist, The

Obesity Society, and American Society for Metabolic and Bariatric Surgery. Surg Obes Relat Dis. 2013; 9(2): 159-191 6 National confidential enquiry into Patient Outcome and Death. Too Lean a Service? a review of the care of patients who underwent bariatric surgery.

London: Dave Terrey; 2012 7 O’Kane M. Bariatric surgery, vitamins, minerals and nutritional monitoring: A survey of current practice within BOMSS. [MSc dissertation]. Leeds, England:

Leeds Metropolitan University; 2013 8 O’Kane M, Pinkney J, Aasheim ET, Barth JH, Batterham RL, Welbourn R. BOMSS Guidelines on peri-operative and post-operative biochemical monitoring and micronutrient replacement for patients undergoing bariatric surgery adults [internet], London: BOMSS. Available from www.bomss.org.uk/wp-content/ uploads/2014/09/bOMSS-guidelines-Final-version1Oct14.pdf 9 Parretti HM, Hughes CA, O’Kane M, Woodcock S, Pryke R. Ten top tips for the management of patients post-bariatric surgery in primary care [internet],

London: Royal College of General Practitioners. Available from www.rcgp.org.uk/clinical-and-research/clinical-resources/nutrition/~/media/Files/CIRC/

Nutrition/Obesity/rcGP-Top-ten-tips-for-post-bariatric-surgery-patients-in-primary-care-Nov-2014.ashx 10 O’Kane M, Pinkney J, Aasheim ET, Barth JH, Batterham RL, Welbourn R. GP Guidance: Management of nutrition following bariatric surgery [internet],

London: BOMSS. Available from www.bomss.org.uk/wp-content/uploads/2014/09/GP_Guidance-Final-version-1Oct141.pdf