Comparative impact of Roux-en-Y gastric bypass, sleeve gastrectomy or diet alone on beta-cell function in insulin-treated type 2 diabetes patients.

Although bariatric surgery is an effective treatment for type 2 diabetes by inducing weight loss and augmenting gut hormone secretion, the immediate effect on beta-cell function itself remains to be elucidated in type 2 diabetes. Therefore, a prospective, randomized trial was performed in 30 patients with insulin-treated type 2 diabetes and a body mass index ≥ 35 kg/m2. Patients were randomly assigned (1:1:1) to Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) in combination with protein-sparing modified fast (PSMF), or to PSMF alone. Eu- and hyperglycemic clamps were performed before and 3 weeks after surgery and/or PSMF initiation. The primary outcome was the evolution of insulin sensitivity and beta-cell function after surgery, calculated using the composite measures of glucose disposal rate, insulin secretion rate, and disposition index (DI). Results revealed that markers of insulin sensitivity increased similarly in all arms (p = 0.43). A higher marker for maximal beta-cell function was observed when comparing SG to PSMF (p = 0.007). The DI showed a clear positive evolution after RYGB and SG, but not after PSMF alone. Altogether, these findings indicate that bariatric surgery results in an immediate beta-cell function recovery in insulin-treated type 2 diabetes.

Understanding the gastrointestinal tract in obesity: From gut motility patterns to enzyme secretion.

BACKGROUND AND PURPOSE: The pathophysiology of obesity has been the product of extensive research, revealing multiple interconnected mechanisms contributing to body weight regulation. The regulation of energy balance involves an intricate network, including the gut-neuroendocrine interplay. As a consequence, research on the gut-brain-microbiota axis in obesity has grown extensively. The physiology of the gastrointestinal tract, far from being underexplored, has significant implications for the development of specific complications in people living with obesity across the fields of gastroenterology, nutrition, and pharmacology. Clinical research indicates higher fasting bile acids serum levels, and blunted postprandial increases in bilious secretions in people living with obesity. Findings are less straightforward for the impact of obesity on gastric emptying with various studies reporting accelerated, normal, or delayed gastric emptying rates. Conversely, the effect of obesity on gastrointestinal pH, gastrointestinal transit, and gastric and pancreatic enzyme secretion is largely unknown. In this review, we explore the current evidence on the gastrointestinal physiology of obesity.

Effect of sleeve gastrectomy and Roux-en-Y gastric bypass on gastrointestinal physiology.

BACKGROUND: Knowledge regarding the gastrointestinal physiology after sleeve gastrectomy and Roux-en-Y gastric bypass is urgently needed to understand, prevent and treat the nutritional and pharmacological complications of bariatric surgery. AIM: To investigate the effect of sleeve gastrectomy and Roux-en-Y gastric bypass on gastrointestinal motility (e.g., transit and pressure), pH, and intestinal bile acid concentration. MATERIAL AND METHODS: An exploratory cross-sectional study was performed in six participants living with obesity, six participants who underwent sleeve gastrectomy, and six participants who underwent Roux-en-Y gastric bypass. During the first visit, a wireless motility capsule (SmartPill©) was ingested after an overnight fast to measure gastrointestinal transit, pH, and pressure. During the second visit, a gastric emptying scintigraphy test of a nutritional drink labeled with 99mTc-colloid by a dual-head SPECT gamma camera was performed to measure gastric emptying half-time (GET1/2). During the third visit, two customized multiple lumen aspiration catheters were positioned to collect fasting and postprandial intestinal fluids to measure bile acid concentration. RESULTS: Immediate pouch emptying (P = 0.0007) and a trend for faster GET1/2 (P = 0.09) were observed in both bariatric groups. There was a tendency for a shorter orocecal transit in participants with sleeve gastrectomy and Roux-en-Y gastric bypass (P = 0.08). The orocecal segment was characterized by a higher 25th percentile pH (P = 0.004) and a trend for a higher median pH in both bariatric groups (P = 0.07). Fasting total bile acid concentration was 7.5-fold higher in the common limb after Roux-en-Y gastric bypass (P < 0.0001) and 3.5-fold higher in the jejunum after sleeve gastrectomy (P = 0.009) compared to obesity. Postprandial bile acid concentration was 3-fold higher in the jejunum after sleeve gastrectomy (P = 0.0004) and 6.5-fold higher in the common limb after Roux-en-Y gastric bypass (P < 0.0001) compared to obesity. CONCLUSION: The anatomical alterations of sleeve gastrectomy and Roux-en-Y gastric bypass have an important impact on gastrointestinal physiology. This data confirms changes in transit and pH and provides the first evidence for altered intraluminal bile acid concentration.

Development and complications of nutritional deficiencies after bariatric surgery.

The clinical effectiveness of bariatric surgery has encouraged the use of bariatric procedures for the treatment of morbid obesity and its comorbidities, with sleeve gastrectomy and Roux-en-Y gastric bypass being the most common procedures. Notwithstanding its success, bariatric procedures are recognised to predispose the development of nutritional deficiencies. A framework is proposed that provides clarity regarding the immediate role of diet, the gastrointestinal tract and the medical state of the patient in the development of nutritional deficiencies after bariatric surgery, while highlighting different enabling resources that may contribute. Untreated, these nutritional deficiencies can progress in the short term into haematological, muscular and neurological complications and in the long term into skeletal complications. In this review, we explore the development of nutritional deficiencies after bariatric surgery through a newly developed conceptual framework. An in-depth understanding will enable the optimisation of the post-operative follow-up, including detecting clinical signs of complications, screening for laboratory abnormalities and treating nutritional deficiencies.

Late complications of biliopancreatic diversion in an older patient: a case report.

BACKGROUND: In the mid-seventies, biliopancreatic diversion became popular as weight-loss surgery procedure. This bariatric procedure combines distal gastric resection and intestinal malabsorption, leading to greater weight loss and improvement of co-morbidities than other bariatric procedures. Nowadays, biliopancreatic diversion has become obsolete due to the high risk of nutritional complications. However, current patients with biliopancreatic diversions are aging. Consequently, geriatricians and general practitioners will encounter them more often and will be faced with the consequences of late complications. CASE PRESENTATION: A 74-year old female presented with weakness, recurrent falls, confusion, episodes of irresponsiveness, anorexia and weight loss. Her medical history included osteoporosis, herpes encephalitis 8 years prior and a biliopancreatic diversion (Scopinaro surgery) at age 52. Cerebral imaging showed herpes sequelae without major atrophy. Delirium was diagnosed with underlying nutritional deficiencies. Biochemical screening indicated vitamin A deficiency, vitamin E deficiency, zinc deficiency and severe hypoalbuminemia. While thiamin level and fasting blood glucose were normal. However, postprandial hyperinsulinemic hypoglycemia was observed with concomitant signs of confusion and blurred consciousness. After initiating parenteral nutrition with additional micronutrient supplementation, a marked improvement was observed in cognitive and physical functioning. CONCLUSIONS: Long-term effects of biliopancreatic diversion remain relatively underreported in older patients. However, the anatomical and physiological changes of the gastrointestinal tract can contribute to the development of metabolic and nutritional complications that may culminate in cognitive impairment, functional decline and delirium. Therefore, it is warranted to evaluate the presence of metabolic disturbances and nutritional complications in older patients after biliopancreatic diversion.

Impact of gastrointestinal tract variability on oral drug absorption and pharmacokinetics: An UNGAP review.

The absorption of oral drugs is frequently plagued by significant variability with potentially serious therapeutic consequences. The source of variability can be traced back to interindividual variability in physiology, differences in special populations (age- and disease-dependent), drug and formulation properties, or food-drug interactions. Clinical evidence for the impact of some of these factors on drug pharmacokinetic variability is mounting: e.g. gastric pH and emptying time, small intestinal fluid properties, differences in pediatrics and the elderly, and surgical changes in gastrointestinal anatomy. However, the link of colonic factors variability (transit time, fluid composition, microbiome), sex differences (male vs. female) and gut-related diseases (chronic constipation, anorexia and cachexia) to drug absorption variability has not been firmly established yet. At the same time, a way to decrease oral drug pharmacokinetic variability is provided by the pharmaceutical industry: clinical evidence suggests that formulation approaches employed during drug development can decrease the variability in oral exposure. This review outlines the main drivers of oral drug exposure variability and potential approaches to overcome them, while highlighting existing knowledge gaps and guiding future studies in this area.

Adaptations in gastrointestinal physiology after sleeve gastrectomy and Roux-en-Y gastric bypass.

Linked to the growing obesity epidemic, demand for bariatric and metabolic surgery has increased, the most common procedures being sleeve gastrectomy and Roux-en-Y gastric bypass. Originally, bariatric procedures were described as purely restrictive, malabsorptive, or combined restrictive-malabsorptive procedures limiting food intake, nutrient absorption, or both. Nowadays, anatomical alterations are known to affect gastrointestinal physiology, which in turn affects the digestion and absorption of nutrients and drugs. Therefore, understanding gastrointestinal physiology is crucial to prevent postoperative nutritional deficiencies and to optimise postoperative drug therapy. Preclinical and clinical research indicates that sleeve gastrectomy accelerates liquid and solid gastric emptying and small intestinal transit, and increases bile acid serum levels, whereas its effects on gastrointestinal acidity, gastric and pancreatic secretions, surface area, and colonic transit remain largely unknown. Roux-en-Y gastric bypass diminishes gastric acid secretion, accelerates liquid gastric emptying, and increases bile acid serum levels, but its effects on intestinal pH, solid gastric emptying, intestinal transit time, gastric enzyme secretions, and surface area remain largely unknown. In this Review, we summarise current knowledge of the effects of these two procedures on gastrointestinal physiology and assess the knowledge gaps.

A Mixed-Method Approach to Develop and Validate an Integrated Food Literacy Tool for Personalized Food Literacy Guidance.

BACKGROUND: Food literacy refers to all practicalities associated with healthy eating. Current food literacy tools are limited in practical use in clinical practice. Therefore, an integrated food literacy tool (IFLT) to assess food literacy and to personalize food literacy guidance was developed and validated. METHODS: Following an iterative process, a food literacy framework was developed and food literacy goals were defined. A corresponding food literacy screener (FLS) to assess food literacy was developed along with an algorithm to provide personalized food literacy guidance based on the food literacy assessment. Content validation of the FLS was assessed by a panel of experts, measuring item and scale content validity index (I/S-CVI) and by the target population in semi structured interviews with 15 adults of reproductive age. Subsequently, an online cross-sectional survey was conducted among 114 adults of reproductive age to evaluate the validity of the FLS. Construct validity was examined against both the validated healthy eating and weight self-efficacy scale and against a food frequency questionnaire assessing healthy eating self-efficacy (HESE) and diet quality, respectively. Reliability was assessed with a two-week test-retest. Pearson correlation tests were conducted. RESULTS: An IFLT consisting of a FLS and corresponding algorithm to personalize food literacy guidance by prioritizing food literacy goals was developed. The IFLT includes 24 food literacy goals, addressed by 17 FLS items. Every item received a weighting factor based on theory and expert opinion to prioritize food literacy goals according to personal needs. Content validity revealed that the FLS was rated relevant by experts (S-CVI = 0.93) and well-understood by the target population. The FLS has a good construct validity as it was positively correlated with diet quality (r = 0.536, p < 0.001) and with HESE (r = 0.685, p < 0.001). It also showed a good test-retest reliability (r = 0.721, p < 0.001). CONCLUSION: The newly developed IFLT is a practically applicable, context specific theory-and expert-based dual purpose tool to assess food literacy and to personalize food literacy guidance by prioritizing individuals' food literacy goals to their needs.

Reversal of Roux-en-Y Gastric Bypass Fails to Facilitate the Management of Recalcitrant Hypocalcaemia Caused by Primary Hypoparathyroidism.

Roux-en-Y gastric bypass (RYGB) is thought to reduce calcium absorption from the gut. Here, we report the case of a patient with a RYGB, who developed primary hypoparathyroidism after a total thyroidectomy, leading to recalcitrant hypocalcaemia. Despite aggressive oral calcium and calcitriol supplementation, she remained hypocalcaemic and required intravenous (IV) calcium supplementation to control her symptoms, and to keep calcium serum levels within an acceptable range. Teriparatide treatment improved calcium levels marginally. This treatment, however, was poorly tolerated and ultimately stopped by the patient. As a last resort, reversal of RYGB was performed to improve calcium absorption from the gut. Unfortunately, IV calcium supplementation remained necessary. This case illustrates that the reversal of RYGB is not always a guarantee for success in managing recalcitrant hypocalcaemia.

Predicting iron absorption from an effervescent iron supplement in obese patients before and after Roux-en-Y gastric bypass: a preliminary study.

BACKGROUND & AIMS: Oral iron absorption is hampered in obese and bariatric patients, especially after Roux-en-Y gastric bypass (RYGB). As a result, iron deficiency, which is common in both patient groups, can be difficult to treat by oral supplements, often necessitating a switch to parenteral administration. The aim of this study was to find possible predictors of the extent of absorption of an effervescent iron gluconate oral supplement, which enables to pre-emptively identify those patients in which oral supplementation is likely to fail. METHODS: The pharmacokinetic properties of 695 mg effervescent iron gluconate (80 mg Fe2+) were assessed in 13 obese patients (female = 10; mean age ± SD: 45.2 ± 12.5years) pre- and six months post-RYGB by measuring serum iron concentrations during 24 hours and by calculating the adjusted for baseline AUC0-24h, Cmax and Tmax. A multivariate regression analysis was performed to investigate the effect of hepcidin concentration, iron and hematologic indices, personal and anthropometric characteristics on iron absorption. Subsequently, Receiver Operating Characteristic (ROC) curves were used to propose the cut-off value for hepcidin concentrations above which obese patients are unlikely to benefit from oral iron supplementation. Data are expressed as mean ± SD. RESULTS: Low iron status persisted after surgery as there was no significant difference observed in TSAT (17.3 ± 5.2 vs. 20.2 ± 6.6%), ferritin (91.8 ± 68.6 vs. 136.2 ± 176.9 µg/L) and hepcidin concentration (32.0 ± 30.1 vs. 28.3 ± 21.3 ng/mL) after RYGB. The absorption of effervescent iron gluconate was similar pre- and post-RYGB [AUC0-24h,pre-RYGB: 28.6 ± 10.8 µg/dL*h; AUC0-24h,post-RYGB: 27.5 ± 9.11 µg/dL*h (P = 0.84)]. Post-RYGB, iron AUC0-24h showed a strong negative correlation with both hepcidin concentrations and TSAT (R=-0.51; P = 0.08 and R=-0.81; P = 0.001), respectively. Pre-RYGB, there was a clear trend for the same negative correlations for hepcidin concentrations and TSAT (R=-0.47; P = 0.11 ;R=-0.41; P = 0.16), respectively. Taking pre-and post-RYGB data together, the negative correlations were confirmed for hepcidin concentrations and TSAT (R=-0.54; P = 0.004; R=-0.60; P = 0.001), respectively. The AUCROC = 0.87 (95%CI 0.71; 1.00) showed an optimal sensitivity/specificity cut-off at hepcidin concentrations of 26.8 ng/mL. CONCLUSIONS: The iron AUC0-24h showed a negative correlation with the hepcidin concentration and TSAT of obese patients, in particular post-RYGB. Therefore, our data support the use of hepcidin concentration and TSAT to distinguish potential responders from non-responders for iron supplementation particularly post-RYGB. Additionally, this study showed that the pharmacokinetic properties of iron gluconate from an effervescent tablet were unaffected by RYGB-surgery.

Iron deficiency after bariatric surgery: what is the real problem?

The growing prevalence of obesity explains the rising interest in bariatric surgery. Compared with non-surgical treatment options, bariatric surgery results in greater and sustained improvements in weight loss, obesity associated complications, all-cause mortality and quality of life. These encouraging metabolic and weight effects come with a downside, namely the risk of nutritional deficiencies. Particularly striking is the risk to develop iron deficiency. Postoperatively, the prevalence of iron deficiency varies between 18 and 53 % after Roux-en-Y gastric bypass and between 1 and 54 % after sleeve gastrectomy. Therefore, preventive strategies and effective treatment options for iron deficiency are crucial to successfully manage the iron status of patients after bariatric surgery. With this review, we discuss the risks and the contributing factors of developing iron deficiency after bariatric surgery. Furthermore, we highlight the discrepancy in the diagnosis of iron deficiency, iron deficiency anaemia and anaemia and highlight the evidence supporting the current nutritional recommendations in the field of bariatric research. In conclusion, we advocate for more nutrition-related research in patient populations in order to provide strong evidence-based guidelines after bariatric surgery.

The relevance of dietary protein after bariatric surgery: what do we know?

PURPOSE OF REVIEW: The growing obesity epidemic is associated with an increased demand for bariatric surgery with Roux-en-Y Gastric Bypass and Sleeve Gastrectomy as the most widely performed procedures. Despite beneficial consequences, nutritional complications may arise because of anatomical and physiological changes of the gastrointestinal tract. The purpose of this review is to provide an update of the recent additions to our understanding of the impact of bariatric surgery on the intake, digestion and absorption of dietary protein. RECENT FINDINGS: After bariatric surgery, protein intake is compromised because of reduced gastric capacity and aversion for certain foods. A minority of patients reaches the recommended protein intake of minimal 60 g per day, which results in the loss of fat-free mass rather than the desired loss of fat mass. Despite inadequate protein intake, protein digestion and absorption do not seem to be impaired suggesting that other mechanisms could counteract the reduced secretion of digestive enzymes and their delayed inlet. SUMMARY: After bariatric surgery, protein supplementation or diet enrichment could attribute to achieve the minimal recommended protein intake and benefit the amount and composition of postoperative weight loss.