Evidence for diminished B12 absorption after gastric bypass: oral supplementation does not prevent low plasma B12 levels in bypass patients

Changes in Nutritional Outcomes After Roux-en-Y Gastric Bypass: A Systematic Review and Meta-Analysis

BACKGROUND

Bariatric surgery (BS) is the most effective treatment for severe obesity and it has beneficial effects on glycemic control and metabolism outcomes. However, the effects of BS on nutritional outcomes are controversial. Therefore, we aimed to evaluate the changes in several nutritional outcomes after Roux-en-Y gastric bypass (RYGB).

METHODS

A comprehensive search was performed using the following databases: PubMed, Embase, Web of Science, Cochrane Library, WanFang and Chinese National Knowledge Infrastructure. The following outcomes were evaluated: vitamin A, 25-hydroxyvitamin D [25(OH)D], calcium, phosphorus, parathormone (PTH), iron, ferritin, vitamin B12, folate, and zinc. The pooled outcomes were expressed as standard mean difference (SMD) and 95% confidence interval (CI) using a random effects model.

RESULTS

Fifty-six studies including 5645 individuals with obesity met the inclusion criteria. Serum 25(OH)D (SMD = 0.78, 95%CI 0.38 to 1.20, P < 0.001), phosphorus (SMD = 0.48, 95%CI 0.22 to 0.74, P < 0.001), PTH (SMD = 0.35, 95%CI 0.11 to 0.59, P = 0.005), vitamin B12 (SMD = 1.11, 95%CI 0.41 to 1.80, P = 0.002), and folate (SMD = 1.53, 95%CI 0.77 to 2.28, P < 0.001) significantly increased after RYGB compared with the baseline. Serum ferritin (SMD =  - 1.67, 95%CI - 2.57 to - 0.77, P < 0.001), vitamin A (SMD =  - 0.64, 95%CI - 0.99 to - 0.29, P < 0.001), and plasma zinc (SMD =  - 0.58, 95%CI - 1.09 to - 0.06, P = 0.027) significantly decreased after RYGB. No significant changes in serum calcium (SMD =  - 0.14, 95%CI - 0.40 to 0.11, P = 0.219) and iron (SMD = 0.26, 95%CI - 0.11 to 0.64, P = 0.165) were observed after RYGB.

CONCLUSIONS

Despite the increased levels of 25(OH)D, phosphorus, vitamin B12 and folate, this meta-analysis revealed the unfavorable nutritional consequences after RYGB.

A Review of Current Trends with Type 2 Diabetes Epidemiology, Aetiology, Pathogenesis, Treatments and Future Perspectives

Type 2 diabetes (T2D), which has currently become a global pandemic, is a metabolic disease largely characterised by impaired insulin secretion and action. Significant progress has been made in understanding T2D aetiology and pathogenesis, which is discussed in this review. Extrapancreatic pathology is also summarised, which demonstrates the highly multifactorial nature of T2D. Glucagon-like peptide (GLP)-1 is an incretin hormone responsible for augmenting insulin secretion from pancreatic beta-cells during the postprandial period. Given that native GLP-1 has a very short half-life, GLP-1 mimetics with a much longer half-life have been developed, which are currently an effective treatment option for T2D by enhancing insulin secretion in patients. Interestingly, there is continual emerging evidence that these therapies alleviate some of the post-diagnosis complications of T2D. Additionally, these therapies have been shown to induce weight loss in patients, suggesting they could be an alternative to bariatric surgery, a procedure associated with numerous complications. Current GLP-1-based therapies all act as orthosteric agonists for the GLP-1 receptor (GLP-1R). Interestingly, it has emerged that GLP-1R also has allosteric binding sites and agonists have been developed for these sites to test their therapeutic potential. Recent studies have also demonstrated the potential of bi- and tri-agonists, which target multiple hormonal receptors including GLP-1R, to more effectively treat T2D. Improved understanding of T2D aetiology/pathogenesis, coupled with the further elucidation of both GLP-1 activity/targets and GLP-1R mechanisms of activation via different agonists, will likely provide better insight into the therapeutic potential of GLP-1-based therapies to treat T2D.

The Effects of Bariatric Surgery on Vitamin B Status and Mental Health

Diet is a modifiable factor that ensures optimal growth, biochemical performance, improved mood and mental functioning. Lack of nutrients, notably vitamin B, has an impact on human health and wellbeing. The United Arab Emirates is facing a serious problem of micronutrient deficiencies because of the growing trend for bariatric surgery, including Roux-en-Y gastric bypass and sleeve gastrectomy. People undergoing bariatric surgery are at high risk of developing neurological, cognitive, and mental disabilities and cardiovascular disease due to deficiency in vitamin B. Vitamin B is involved in neurotransmitter synthesis, including γ-aminobutyric acid, serotonin, dopamine, and noradrenaline. Deficiency of vitamin B increases the risk of depression, anxiety, dementia and Alzheimer's disease. In addition, vitamin B deficiency can disrupt the methylation of homocysteine, leading to hyperhomocysteinemia. Elevated homocysteine levels are detrimental to human health. Vitamin B deficiency also suppresses immune function, increases the production of pro-inflammatory cytokines and upregulates NF-κB. Considering the important functions of vitamin B and the severe consequences associated with its deficiency following bariatric surgery, proper dietary intervention and administration of adequate supplements should be considered to prevent negative clinical outcomes.

Iron, Vitamin B12, Folate and Copper Deficiency After Bariatric Surgery and the Impact on Anaemia: a Systematic Review

Bariatric surgery may increase the risk of iron, vitamin B₁₂, folate and copper deficiencies, which can cause anaemia. This review aims to critique the evidence on the prevalence of these nutritional deficiencies and the impact on anaemia in the first 12 months after surgery. PRISMA and MOOSE frameworks, the NHMRC evidence hierarchy and The Academy of Nutrition and Dietetics bias tool were used to systematically critique current literature. Seventeen studies reported on deficiency prevalence with the majority being of low quality. Important confounders to serum micronutrient levels were not adequately considered. Results on the prevalence of nutritional anaemias were also lacking. Further investigation into the prevalence of iron, vitamin B₁₂, folate and copper deficiency and its impact on anaemia in bariatric surgery is needed.

Oral Vitamin B12 Supplementation After Roux-en-Y Gastric Bypass: a Systematic Review

BACKGROUND

Many respectable guidelines recommend lifelong vitamin B₁₂ injections for Roux-en-Y gastric bypass (RYGB) patients in the absence of lack of consensus on the efficacy of oral route of prophylaxis and the appropriate doses needed for this purpose. The purpose of this review was to examine the published English language scientific literature in accordance with PRISMA principles to find out if orally given vitamin B₁₂ is adequate for prophylactic purposes in RYGB patients and the appropriate dosages needed for this purpose if it is.

METHODS

We examined the PubMed database for all English language articles examining various doses of oral vitamin B₁₂ supplementation after proximal RYGB in adult patients. The search revealed 19 such articles.

RESULTS

The data suggest that oral vitamin B₁₂ supplementation doses of ≤ 15 μg daily are insufficient to prevent deficiency in RYGB patients. Higher supplementation doses show better results and it appears that a dose of 600.0 μg vitamin B₁₂ daily is superior to 350.0 μg daily suggesting an incremental dose-response curve. It further appears that supplementation doses of 1000.0 μg vitamin B₁₂ daily lead to an increase in B₁₂ levels and are sufficient for the prevention of its deficiency in most RYGB patients.

CONCLUSION

The review finds that oral supplementation doses of ≤ 15 μg vitamin B₁₂ daily are inadequate for prophylaxis of vitamin B₁₂ deficiency in adult RYGB patients but doses of 1000 μg vitamin B₁₂ daily might be adequate. Future studies need to examine this and even higher oral doses for vitamin B₁₂ supplementation for patients undergoing RYGB.

Does Bariatric Surgery Cause Vitamin A, B1, C or E Deficiency? A Systematic Review

BACKGROUND

The restrictive and/or malabsorptive nature of bariatric surgery may increase the risk for micronutrient deficiencies. This systematic review aimed to identify and critique the evidence for vitamin A, B1, C or E deficiencies associated with bariatric surgery.

METHODS

This review utilised PRISMA and MOOSE frameworks with NHMRC evidence hierarchy and the American Dietetic Association bias tool to assess the quality of articles.

RESULTS

Twenty-one articles were included and once critiqued all studies were of level IV grade and neutral or negative in quality. The relevance of measuring micronutrient supplementation and inflammatory markers for validity of serum vitamins is absent within the literature.

CONCLUSIONS

Future research is needed to investigate the risk of deficiency for these procedures with focus on confounders to serum micronutrients.

Malnutrition in obesity before and after bariatric surgery

Bariatric surgeries are considered the only effective way of weight loss therapy in morbidly obese patients, i.e. body mass index ≥ 35. However, micronutrient deficiencies and malnutrition are common after most bariatric procedures and thus, pre- and postoperative nutritional assessment and corrections are advised. The present review is presented in an effort to describe in some detail about prevalence, and mechanisms of macro- and micronutrient deficiencies in obese and post-bariatric surgery individuals. We also aimed to summarize the data on screening and supplementation of macro- and micronutrients before and after bariatric surgeries.

Neurological complications of bariatric surgery

Obesity is reaching pandemic proportions, and the number of bariatric surgeries is increasing. Neurological complications of bariatric procedures are more and more frequently reported and physicians need to recognize and be able to manage them. Neurological complications may result from mechanical or inflammatory mechanisms, but mainly from nutritional deficiencies. Vitamin B12, folate, thiamine, vitamin D, and vitamin E are the most frequent deficiencies. Different patterns of complications can be observed that may differ from time to presentation. At an early stage, immediate peripherical nerve injury, Wernicke's encephalopathy, and polyradiculoneuropathy are the most frequent. Late complications may appear after years and include optic neuropathy, myelopathy, peripherical neuropathy, and myopathy. Bariatric surgery patients should benefit from careful nutritional follow-up with routine monitoring of micronutrients at 6 weeks and 3, 6, and 12 months post-op and then annually after surgery, and multivitamin supplementation for life.

[Abdominoplasty complications: particularities of the post-bariatric patients within a 238 patients series]

BACKGROUND

Obesity is one of the health issues that is recently worldwide increasing, as well as in France. Variety of procedures of bariatric surgery have been developed over the past decade and are performed for morbid obesity hence. The demand of plastic surgery increased for body contouring and reshaping after dramatic weight loss, in which the abdominoplasty is considered as one of the most common procedures. The purpose of this study is to clarify the differences between the post-bariatric patients and others, and their influence on the occurrence of complications following abdominoplasty.

PATIENTS AND METHODS

Retrospective study involving a group of post-abdominoplasty patients collected from the same center between January 2000 and December 2010.

RESULTS

Among 238 reviewed patients' files; 114 of them are post-bariatric patients, and 124 are non-bariatric patients. Several differences were found between these two groups of patients including the maximum BMI, BMI at the time of surgery, the rates of cardiovascular risk factors, and a longer operative time in the post-bariatric group. The complication rate in these patients was significantly higher (55.3% against 26.6%) with mainly healing problems. Major maximum weight, obesity at the time of surgery, long operative time and postoperative drainage system are all considered as risk factors, which carry high rate of complications.

CONCLUSION

It appears that abdominoplasty in post-bariatric patients requires specific care because of particularities inherent in this population.

The neurologic complications of bariatric surgery

Bariatric surgery has been increasingly employed to manage morbid obesity. Approximately 150000 bariatric procedures are performed in the US annually. Neurologic complications arise in as many as 5% of individuals having this surgery. Although the etiology of some of these complications remains obscure, the majority are the consequence of vitamin (most commonly thiamine and vitamin B12) or mineral (most commonly copper) deficiency and familiarity with these disorders is essential. Their rapid diagnosis and appropriate treatment is essential to avoid long-term, irreversible consequences including, in some instances, death.

Vitamin B12 deficiency in patients undergoing bariatric surgery: preventive strategies and key recommendations

BACKGROUND

Advances in bariatric surgery have brought about a paradigm shift in the management of obesity, with benefits extending beyond weight loss. However, nutritional deficiencies are an inherent problem in the postoperative period and often require lifelong supplementation. Vitamin B12, also referred to as cobalamin, is one of the most common micronutrient deficiencies affecting this population. This review explores the pathophysiology of cobalamin deficiency in patients undergoing bariatric surgery and provides an overview of the effectiveness of various available vitamin B12 formulations.

METHODS

To identify the relevant literature, a systematic review of MEDLINE was conducted from the earliest dates through September 2012 for English-language articles describing the prevention and management of vitamin B12 deficiency in patients undergoing bariatric surgery.

RESULTS

Intramuscular vitamin B12 continues to be the gold standard of therapy for vitamin B12 deficiency, especially in symptomatic patients. In select patients with asymptomatic vitamin B12 deficiency after Roux-en-Y gastric bypass (RYGB), high-dose oral cyanocobalamin should be given a consideration, especially when there are concerns with the adherence to intramuscular therapy or if compliance comes into question. Unlike patients post-RYGB, those undergoing restrictive procedures such as gastric banding and sleeve gastrectomy may be maintained postoperatively on a lower-dose daily vitamin B12 supplementation. Efficacy data of nasal and sublingual routes for maintenance therapy is currently awaited.

CONCLUSION

Patients undergoing bariatric surgery must be continuously educated on proper nutrition, the risk of developing significant vitamin B12 deficiency, and the role of supplements in avoiding catastrophic consequences.

Vitamin, mineral, and drug absorption following bariatric surgery

The prevalence of obesity continues to rise throughout the world. Increasingly, bariatric surgery is used for those with morbid obesity as a pivotal approach to achieve weight loss. Along with substantial weight loss, malabsorption of essential vitamins, minerals, and drugs also occurs. Therefore, more than ever, a better understanding of the physiology and mechanisms by which these deficiencies occur is essential. We review the normal physiology of vitamin, mineral, and drug absorption. This is followed by a description of currently performed bariatric surgeries in the United States. A detailed review of specific nutrient and mineral deficiency states is presented, based on the most significant studies published in the last two decades. Of note, screening and supplementation recommendations have been included. Drug absorption data after these procedures is presented and discussed. Studies were identified by searching the Cochrane Registry and MEDLINE using relevant search terms, as well as through review of the reference section of included manuscripts.

CONCLUSIONS

Bariatric surgery can be effectively used to achieve sustainable weight-loss in morbidly obese patients. It simultaneously brings forth important functional consequences on nutrient deficiencies and drug absorption that clinician's must be aware of. Further prospective, randomized research on specific procedures and deficiencies is required.

Nutrient deficiencies after gastric bypass surgery

Bariatric surgery, and in particular, gastric bypass, is an increasingly utilized and successful approach for long-term treatment of obesity and amelioration of comorbidities. Nutrient deficiencies after surgery are common and have multiple causes. Preoperative factors include obesity, which appears to be associated with risk for several nutrient deficiencies, and preoperative weight loss. Postoperatively, reduced food intake, suboptimal dietary quality, altered digestion and absorption, and nonadherence with supplementation regimens contribute to risk of deficiency. The most common clinically relevant micronutrient deficiencies after gastric bypass include thiamine, vitamin B₁₂, vitamin D, iron, and copper. Reports of deficiencies of many other nutrients, some with severe clinical manifestations, are relatively sporadic. Diet and multivitamin use are unlikely to consistently prevent deficiency, thus supplementation with additional specific nutrients is often needed. Though optimal supplement regimens are not yet defined, most micronutrient deficiencies after gastric bypass currently can be prevented or treated by appropriate supplementation.

Focal brain atrophy in gastric bypass patients with cognitive complaints

Recently, we have identified a series of patients presenting with cognitive complaints after gastric bypass, without any identifiable etiology. We aimed to determine if focal brain atrophy could account for the complaints. A retrospective case series was performed to identify patients with cognitive complaints following gastric bypass who had a volumetric MRI. Voxel-based morphometry was used to assess patterns of grey matter loss in all 10 patients identified, compared to 10 age and gender-matched controls. All patients had undergone Roux-en-Y gastric bypass surgery at a median age of 54 (range: 46-64). Cognitive complaints developed at a median age of 57 (52-69). Formal neuropsychometric testing revealed only minor deficits. No nutritional abnormalities were identified. Voxel-based morphometry demonstrated focal thalamic atrophy in the gastric bypass patients when compared to controls. Patients with cognitive complaints after gastric bypass surgery may have focal thalamic brain atrophy that could result in cognitive impairment.

Dietary intake and eating behavior after bariatric surgery: threats to weight loss maintenance and strategies for success

During the past decade, bariatric surgery has become an increasingly popular treatment option for the growing number of individuals with extreme obesity. For most individuals, the size and durability of the weight loss and improvements in co-morbidity and mortality have far surpassed those typically seen with behavioral modification and pharmacotherapy. A significant minority of patients, however, will experience suboptimal outcomes, including less than expected weight loss, premature weight regain, and frequent vomiting and/or gastric dumping. The reasons for these outcomes are not well understood, but likely involve both behavioral and physiologic processes. The present review highlights current knowledge on the changes in dietary intake and eating behavior that occur after bariatric surgery in terms of the potential threats these changes might pose to long-term postoperative success. The paper also identifies several strategies from the nonsurgical weight loss literature that might help optimize long-term weight maintenance after surgery.

Wound healing process in post-bariatric patients: an experimental evaluation

Bariatric surgery is the most effective treatment for morbid obesity. Despite this, side effects are recorded. One of them is redundant skin hanging from the patients' body causing both aesthetical and functional deformities. They can only be corrected with body contouring surgery, whose wound complication rate is very high in previously obese population. Despite several hypotheses, an adequate explanation is still awaited. The aim of our study was to evaluate the wound healing process in post-bariatric patients. Seven patients, six women and one man, were enrolled. They all were nonsmokers and nondiabetic. They all underwent biliopancreatic diversion (BPD). After 36 months, abdominoplasty was performed. Biochemical parameters before and after bariatric surgery were evaluated. The content of total protein and hydroxyproline was assessed in multiple scar biopsies before and after BPD. Abdominoplasty horizontal scar skin samples were subjected to histological evaluation with Weigert-Van Gieson stain for elastic fibers and connectivum. All biochemical parameters analyzed were reduced post-BPD compared to the preoperative period. Tissue proteins were significantly reduced after BPD both in their totality and as hydroxyproline and hydroxyproline/total tissue protein. Histological evaluation revealed abnormal dermal elastic and collagen fibers. The cause of aberrant healing in massive weight loss body contouring is likely multifactorial. A relationship between nutritional state, wound collagen accumulation, and elastic fiber content seems to be only partially involved. The high mechanical stress of tissues before BPD probably influences the wound healing process after BPD.

Endocrine and nutritional management of the post-bariatric surgery patient: an Endocrine Society Clinical Practice Guideline

OBJECTIVE

We sought to provide guidelines for the nutritional and endocrine management of adults after bariatric surgery, including those with diabetes mellitus. The focus is on the immediate postoperative period and long-term management to prevent complications, weight regain, and progression of obesity-associated comorbidities. The treatment of specific disorders is only summarized.

PARTICIPANTS

The Task Force was composed of a chair, five additional experts, a methodologist, and a medical writer. It received no corporate funding or remuneration.

CONCLUSIONS

Bariatric surgery is not a guarantee of successful weight loss and maintenance. Increasingly, patients regain weight, especially those undergoing restrictive surgeries such as laparoscopic banding rather than malabsorptive surgeries such as Roux-en-Y bypass. Active nutritional patient education and clinical management to prevent and detect nutritional deficiencies are recommended for all patients undergoing bariatric surgery. Management of potential nutritional deficiencies is particularly important for patients undergoing malabsorptive procedures, and strategies should be employed to compensate for food intolerance in patients who have had a malabsorptive procedure to reduce the risk for clinically important nutritional deficiencies. To enhance the transition to life after bariatric surgery and to prevent weight regain and nutritional complications, all patients should receive care from a multidisciplinary team including an experienced primary care physician, endocrinologist, or gastroenterologist and consider enrolling postoperatively in a comprehensive program for nutrition and lifestyle management. Future research should address the effectiveness of intensive postoperative nutritional and endocrine care in reducing morbidity and mortality from obesity-associated chronic diseases.

Nutritional assessment of bariatric surgery patients presenting for plastic surgery: a prospective analysis

BACKGROUND

Assessment of nutritional status in the growing postbariatric patient population remains controversial. Previous literature suggests that these patients have poor nutrition that may have adverse effects on surgical outcomes. The authors sought to determine the optimal method of nutritional assessment in postbariatric patients.

METHODS

One hundred patients presenting for body contouring after bariatric surgery were consecutively enrolled in an institutional review board-approved prospective study. A trained nutritionist assessed protein and calorie intake. All patients underwent baseline laboratory assessment.

RESULTS

Eighteen percent of subjects had less than the recommended daily protein intake. Hypoalbuminemia was observed in 13.8 percent of subjects, with hypoprealbuminemia in 6.5 percent. Nearly forty percent of all patients had evidence of iron deficiency, with vitamin B12 deficiency present in 14.5 percent. Ten percent of subjects (all women) were confirmed to have iron deficiency anemia. Impaired fasting glucose was seen in 6.2 percent of subjects, whereas 3.6 percent had hemoglobin A1c levels greater than 6.5. Increasing age (odds ratio, 1.07) and greater change in body mass index (odds ratio, 1.11) were predictors of low protein intake. Dumping syndrome led to 13.3 times increased odds of low albumin levels.

CONCLUSIONS

The results suggest that inadequate nutrition is common among postbariatric patients presenting for body contouring. The lack of correlation between methods of nutritional assessment supports the combination of multiple methods in determining overall nutritional status. The presence of dumping syndrome, a large change in body mass index, and advanced age may help to identify patients with an increased risk of nutritional deficiency.

Nutritional management after Roux-en-Y gastric bypass

Changes in the anatomy and function of the gastrointestinal tract after bariatric surgery markedly change patients' eating patterns. Malnutrition is a significant risk associated with all bariatric procedures, which can lead to dangerous nutritional deficiencies. However, if correct patient selection is conducted and if patients receive thorough preoperative nutrition education and postoperative nutritional follow-up, these deficiencies are largely preventable. Nurses are important members of the multidisciplinary team; assisting in patient selection, providing hands-on care, and educating the patient on the surgical process and post-operative dietary restrictions. It is critical for nurses to understand immediate and projected nutritional consequences of surgery, in order to monitor the patient for diet tolerance and nutrient deficiency symptoms, to encourage dietary compliance, and to reinforce the long-term dietary restrictions. With appropriate supplementation and patient compliance, all nutritional deficiencies can be avoided or corrected.

Neurologic presentations of nutritional deficiencies

Optimal functioning of the central and peripheral nervous system is dependent on a constant supply of appropriate nutrients. The first section of this review discusses neurologic manifestations related to deficiency of key nutrients such as vitamin B(12), folate, copper, vitamin E, thiamine, and others. The second section addresses neurologic complications related to bariatric surgery. The third sections includes neurologic presentations caused by nutrient deficiencies in the setting of alcoholism. The concluding section addresses neurologic deficiency diseases that have a geographic predilection.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery medical guidelines for clinical practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist health-care professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice for the perioperative nutritional, metabolic, and nonsurgical support of the bariatric surgery patient

American Association of Clinical Endocrinologists, The Obesity Society, and American Society for Metabolic & Bariatric Surgery Medical Guidelines for Clinical Practice are systematically developed statements to assist healthcare professionals in medical decision making for specific clinical conditions. Most of the content herein is based on literature reviews. In areas of uncertainty, professional judgment was applied. These guidelines are a working document that reflects the state of the field at the time of publication. Because rapid changes in this area are expected, periodic revisions are inevitable. We encourage medical professionals to use this information in conjunction with their best clinical judgment. The presented recommendations may not be appropriate in all situations. Any decision by practitioners to apply these guidelines must be made in light of local resources and individual patient circumstances. The American Society for Parenteral & Enteral Nutrition fully endorses sections of these guidelines that address the metabolic and nutritional management of the bariatric surgical patient.

Nutritional deficiencies after bariatric surgery

A current review of nutritional complications following bariatric procedures is presented, focusing on the most common and clinically important deficiencies. A brief outline of nutritional supplementation protocol is presented, highlighting the need for a standardized, national or international set of guidelines for pre- and postoperative nutritional screening and appropriate supplementation.

Nutritional neuropathies

Optimal functioning of the central and peripheral nervous system is dependent on appropriate nutrients. Neurologic consequences of nutritional deficiencies are not restricted to underdeveloped countries. Multiple nutritional deficiencies can coexist. Obesity is of particular concern in the developed world. The rising rate of bariatric surgery are accompanied by neurologic complications related to nutrient deficiencies. Prognosis depends on prompt recognition and institution of appropriate therapy. This review discusses peripheral nervous system manifestations related to the deficiency of key nutrients, neurologic complications associated with bariatric surgery, and conditions that have a geographic significance associated with bariatric surgery and certain conditions that have a geographic predilection.

Nutritional deficiency after gastric bypass: diagnosis, prevention and treatment

In recent years, the recourse to obesity surgery to treat morbid obesities has grown. The number of "malabsorptive" interventions, such as the gastric bypass (RYGB: Roux-en-Y gastric bypass) increases each year. The RYGB, which combines two mechanisms promoting weight loss, restriction and malabsorption, has proven its effectiveness in term of weight loss and improvement of obesity-associated co-morbidities. However this intervention involves a profound change in digestive physiology and is the source of nutritional and metabolic complications. The deficits observed most frequently concern proteins, iron, calcium, vitamin B12 and vitamin D. The deficiencies in vitamin B1 are rare but potentially serious. Multidisciplinary follow-up is essential to ensure prevention, diagnosis and treatment of these complications. Based on an analysis of the literature, this article summarizes the various nutritional complications observed after RYGB and the means to diagnose it. It proposes practical recommendations for follow-up, preventive supplementation and treatment of these deficiencies, both generally and in the more specific case of a pregnancy after RYGB.

Neurologic complications after surgery for obesity

Bariatric surgical procedures are increasingly common. In this review, we characterize the neurologic complications of such procedures, including their mechanisms, frequency, and prognosis. Literature review yielded 50 case reports of 96 patients with neurologic symptoms after bariatric procedures. The most common presentations were peripheral neuropathy in 60 (62%) and encephalopathy in 30 (31%). Among the 60 patients with peripheral neuropathy, 40 (67%) had a polyneuropathy and 18 (30%) had mononeuropathies, which included 17 (94%) with meralgia paresthetica and 1 with foot drop. Neurologic emergencies including Wernicke's encephalopathy, rhabdomyolysis, and Guillain-Barré syndrome were also reported. In 18 surgical series reported between 1976 and 2004, 133 of 9996 patients (1.3%) were recognized to have neurologic complications (range: 0.08-16%). The only prospective study reported a neurologic complication rate of 4.6%, and a controlled retrospective study identified 16% of patients with peripheral neuropathy. There is evidence to suggest a role for inflammation or an immunologic mechanism in neuropathy after gastric bypass. Micronutrient deficiencies following gastric bypass were evaluated in 957 patients in 8 reports. A total of 236 (25%) had vitamin B(12) deficiency and 11 (1%) had thiamine deficiency. Routine monitoring of micronutrient levels and prompt recognition of neurological complications can reduce morbidity associated with these procedures.

Psychosocial and behavioral aspects of bariatric surgery

Bariatric surgery has become an increasingly popular treatment option for individuals with extreme obesity (defined as a BMI > or = 40 kg/m2) or those with less severe obesity accompanied by significant comorbidities. Sustained postoperative weight loss and improvements in obesity-related health problems make bariatric surgery the most effective treatment for this population. Nevertheless, most experts agree that psychosocial and behavioral factors contribute to successful postoperative outcomes. This paper reviews the literature on the preoperative psychosocial status, eating behaviors, and quality of life of patients who seek bariatric surgery. In addition, the paper examines studies that investigated changes in these factors postoperatively. The review concludes with an agenda for future research in this area.

Nutritional concerns related to Roux-en-Y gastric bypass: what every clinician needs to know

Weight loss surgery, particularly the Roux-en-Y gastric bypass (REYGB), has become a popular treatment strategy for obesity. Often the only measure of success is the amount of weight lost following surgery. Unfortunately the nutritional adequacy of the postoperative diet has frequently been overlooked, and in the months to years that follow, nutritional deficiencies have become apparent, including protein-calorie malnutrition and various vitamin and mineral deficiencies contributing to medical illnesses and limiting optimal health. Therefore, patients require close monitoring following REYGB, with special regard to the rapidity of weight loss and vigilant screening for signs and symptoms of subclinical and clinical nutritional deficiencies. Several specific nutrients require close surveillance postoperatively to prevent life-threatening complications related to deficient states. This article addresses nutritional concerns associated with REYGB with fastidious focus on recognition and treatment of the nutritional deficiencies and promotion of nutritional health following REYGB. Recommendations regarding nutritional intake following REYGB are based on available scientific data, albeit limited. In cases where data do not exist, expert or consensus opinion is provided and recommendations for future research are given. Ultimately, clinical application of this information will contribute to the prevention of nutrition-related illness associated with REYGB.

Follow-up of nutritional and metabolic problems after bariatric surgery

Over the next several years, the number of patients who will have had bariatric surgery for morbid obesity will reach close to a million. Several well-described nutritional problems such as B12 and iron deficiency will be noted in these patients. Many of these patients will be lost to the original surgeon and will now be in the care of the "other physicians." These and other mineral and vitamin problems will need to be screened and treated. If these problems are left undiagnosed, severe and irreparable problems can result. Early problems, such as vomiting and dumping syndrome, will be easily recognized and treated, but other long-term problems, such as changes in bone metabolism, will need to be monitored. Again, if some of these long-term problems are not addressed in a timely fashion, then eventual treatment becomes much more difficult. This commentary will cover the common as well newer problems that are now developing in the patient who has had bariatric surgery. Patients who have undergone bariatric surgery require medical follow-up for reasons that are often determined by the type of surgical procedure performed. The majority of this review will deal with patients who have had the standard Roux-en-Y gastric bypass, which is a primarily restrictive procedure with a mild component of noncaloric malabsorption. At the end of this report, a short section will be devoted to the problems associated with the malabsorptive procedures.

Perioperative management of the post-gastric-bypass patient presenting for body contour surgery

Bariatric surgery has evolved as an effective and relatively safe treatment for morbid obesity. With nearly every region of the body as a potential operative site and an unprecedented number of surgical procedures available, we must give attention to thoughtful perioperative management. Bariatric surgery is a life-changing event for the morbidly obese patient, and the body contouring that follows weight loss often has an equally profound effect. Plastic surgeons must strive to maintain the highest level of safety in this pursuit. The authors address issues surrounding preoperative evaluation and measures to minimize the risk of complications.

Current concepts in cobalamin deficiency

The application of sensitive metabolic tests, such as the deoxyuridine suppression test and measurement of homocysteine and methylmalonic acid, to cobalamin status has identified the entity of mild, preclinical cobalamin deficiency. This state, common in the elderly, responds to cobalamin therapy. Preclinical deficiency may exist within the nervous system as well, although this requires further study. Nevertheless, it is well to remember that not all low cobalamin levels and not all abnormal metabolite results reflect cobalamin deficiency. Interpretation of metabolic results still requires caution, as do proposals to raise the cut-off point for low cobalamin levels to capture some normal levels that are associated with metabolic abnormality. The recognition of mild, preclinical deficiency has opened up many important issues. These include identifying its causes, what should be done about it, and what the clinical impact of the hyperhomocysteinemia itself is. Although malabsorptive disorders, especially food-cobalamin malabsorption, underlie about half of all cases of preclinical deficiency, no cause can be found in the remainder of these cases; poor dietary intake appears to be uncommon. In addition, unusual states of neurologically symptomatic cobalamin deficiency are being recognized, such as nitrous oxide exposure in patients with unrecognized deficiency and severe deficiency in children of mildly deficient mothers. All of these have broadened and complicated the picture of cobalamin deficiency while providing greater opportunities for prevention.

Managing the obese patient after bariatric surgery: a case report of severe malnutrition and review of the literature

Surgery is now considered to be the most effective treatment for reducing weight and maintaining weight loss in patients with clinically severe obesity. Although the jejuno-ileal bypass has been abandoned, the vertical banded gastroplasty (VBG) and Roux-en-Y gastric bypass (RYGB) operations are now commonly performed. A third operation, the bilio-pancreatic diversion (BPD), is performed less frequently. The RYGB and BPD procedures cause predictable selective micronutrient deficiencies that can be avoided by early supplementation. Surgical complications from all of these procedures may result in more severe forms of malnutrition. This article is intended to familiarize the nutrition support specialist with the anatomic and physiologic changes produced by these procedures, the resulting nutritional deficiencies and recommended supplementation, and the manifestations of severe malnutrition caused by complications. A case of severe malnutrition after RYGB surgery is reported for illustration.

Obesity surgery: a model of programmed undernutrition

Surgical treatment of obesity (bariatric surgery) is the only effective long term solution for many patients. The procedures are designed to produce reduced intake, various degrees of malabsorption of nutrients, or both. Micronutrient deficiencies, especially those involved in erythropoiesis and bone metabolism, are common to nearly all bariatric surgery. They are inconsistently responsive to supplementation. The pattern of deficiency associated with gastrointestinal bypass procedures suggests that absorption of micronutrients is more dependent upon the functioning of the gut as a whole than the capacity of any single segment.

Malabsorption of food cobalamin

Food-cobalamin malabsorption is marked by the inability to release cobalamin from food, which therefore cannot be taken up by intrinsic factor for absorption. The defect is not detectable by classical clinical tests like the Schilling test which are all based on the absorption of free, crystalline cobalamin. Tests of food-cobalamin absorption have been devised, the most popular ones using cobalamin bound to eggs or to chicken serum. The disparity between the abnormal results of these tests and the normal results with the Schilling test defines the disorder of food-cobalamin malabsorption. Release of cobalamin from food requires acid and pepsin, and most food-cobalamin malabsorptive states can be traced to gastric defects. However, other mechanisms may also play a role. The malabsorption is limited to food cobalamin and any free cobalamin, presumably including recycled biliary cobalamin, will be absorbed normally, which may explain its frequently insidious nature. The effect on cobalamin status covers a broad spectrum. At one extreme, some individuals, perhaps in the earliest stages, have normal cobalamin status, while at the other extreme may be found deficiency every bit as severe as in the most florid case of pernicious anaemia. Most often, however, the deficiency is mild, frequently marked by only a low serum cobalamin level, mild evidence of metabolic insufficiency and, sometimes, minimal clinical sequelae. Moreover, in some cases the gastric defect progresses and intrinsic factor secretion is affected, thus transforming into classical pernicious anaemia; this is not inevitable, however, and probably occurs in only a minority of patients. The course of food-cobalamin malabsorption is therefore a varied one. Nevertheless, it may be the most common cause of subtle or mild cobalamin deficiency and it is also sometimes associated with severe deficiency. Its identification and treatment need to be considered more widely in the clinical setting.

Effect of hypochlorhydria due to omeprazole treatment or atrophic gastritis on protein-bound vitamin B12 absorption

OBJECTIVE

To investigate the effects of hypochlorhydria and acidic drink ingestion on protein-bound vitamin B12 absorption in elderly subjects.

METHODS

Absorption of protein-bound vitamin B12 was examined in elderly normal subjects (n = 8), and in hypochlorhydric subjects due to omeprazole treatment (n = 8) or with atrophic gastritis (n = 3). Subjects underwent absorption tests of protein-bound vitamin B12 ingested with water, cranberry juice and 0.1 N hydrochloric acid.

RESULTS

Protein-bound vitamin B12 absorption was lower in the omeprazole-treated group (0.50%) compared to the normal group (1.21%; p < 0.001). With cranberry juice ingestion, the omeprazole-treated group showed an increase in absorbed protein-bound vitamin B12 (p = 0.025). With dilute hydrochloric acid ingestion, there was a further increase in vitamin B12 absorption (p < 0.001).

CONCLUSION

Omeprazole causes protein-bound vitamin B12 malabsorption, and ingestion of an acidic drink improves protein-bound vitamin B12 absorption.