Gastrointestinal transit, appetite, and energy balance in gastrectomized patients

Ultraprocessed Foods and Obesity Risk: A Critical Review of Reported Mechanisms

Epidemiologic evidence supports a positive association between ultraprocessed food (UPF) consumption and body mass index. This has led to recommendations to avoid UPFs despite very limited evidence establishing causality. Many mechanisms have been proposed, and this review critically aimed to evaluate selected possibilities for specificity, clarity, and consistency related to food choice (i.e., low cost, shelf-life, food packaging, hyperpalatability, and stimulation of hunger/suppression of fullness); food composition (i.e., macronutrients, food texture, added sugar, fat and salt, energy density, low-calorie sweeteners, and additives); and digestive processes (i.e., oral processing/eating rate, gastric emptying time, gastrointestinal transit time, and microbiome). For some purported mechanisms (e.g., fiber content, texture, gastric emptying, and intestinal transit time), data directly contrasting the effects of UPF and non-UPF intake on the indices of appetite, food intake, and adiposity are available and do not support a unique contribution of UPFs. In other instances, data are not available (e.g., microbiome and food additives) or are insufficient (e.g., packaging, food cost, shelf-life, macronutrient intake, and appetite stimulation) to judge the benefits versus the risks of UPF avoidance. There are yet other evoked mechanisms in which the preponderance of evidence indicates ingredients in UPFs actually moderate body weight (e.g., low-calorie sweetener use for weight management; beverage consumption as it dilutes energy density; and higher fat content because it reduces glycemic responses). Because avoidance of UPFs holds potential adverse effects (e.g., reduced diet quality, increased risk of food poisoning, and food wastage), it is imprudent to make recommendations regarding their role in diets before causality and plausible mechanisms have been verified.

The Problem of Appetite Loss After Major Abdominal Surgery

Objective:

To systematically review the problem of appetite loss after major abdominal surgery.

Summary of Background Data:

Appetite loss is a common problem after major abdominal surgery. Understanding of etiology and treatment options is limited.

Methods:

We searched Medline, Cochrane Central Register of Controlled Trials, and Web of Science for studies describing postoperative appetite loss. Data were extracted to clarify definition, etiology, measurement, surgical influence, pharmacological, and nonpharmacological treatment. PROSPERO registration ID: CRD42021224489.

Results:

Out of 6144 articles, we included 165 studies, 121 of which were also analyzed quantitatively. A total of 19.8% were randomized, controlled trials (n = 24) and 80.2% were nonrandomized studies (n = 97). The studies included 20,506 patients undergoing the following surgeries: esophageal (n = 33 studies), gastric (n = 48), small bowel (n = 6), colon (n = 27), rectal (n = 20), hepatobiliary (n = 6), and pancreatic (n = 13). Appetite was mostly measured with the Quality of Life Questionnaire of the European Organization for Research and Treatment of Cancer (EORTC QLQ C30, n = 54). In a meta-analysis of 4 randomized controlled trials gum chewing reduced time to first hunger by 21.2 hours among patients who had bowel surgery. Other reported treatment options with positive effects on appetite but lower levels of evidence include, among others, intravenous ghrelin administration, the oral Japanese herbal medicine Rikkunshito, oral mosapride citrate, multidisciplin-ary-counseling, and watching cooking shows. No studies investigated the effect of well-known appetite stimulants such as cannabinoids, steroids, or megestrol acetate on surgical patients.

Conclusions:

Appetite loss after major abdominal surgery is common and associated with increased morbidity and reduced quality of life. Recent studies demonstrate the influence of reduced gastric volume and ghrelin secretion, and increased satiety hormone secretion. There are various treatment options available including level IA evidence for postoperative gum chewing. In the future, surgical trials should include the assessment of appetite loss as a relevant outcome measure.

Internally regulated eating style: a comprehensive theoretical framework

Internally regulated eating style, the eating style that is driven by internal bodily sensations of hunger and satiation, is a concept that has received increasing attention in the literature and health practice over the last decades. The various attempts that have been made so far to conceptualise internally regulated eating have taken place independently of one another, and each sheds light on only parts of the total picture of what defines internally regulated eating. This has resulted in a literature that is rather fragmented. More importantly, it is not yet clear which are the characteristics that comprise this eating style. In this paper, we identify and describe the full spectrum of these characteristics, namely, sensitivity to internal hunger and satiation signals, self-efficacy in using internal hunger and satiation signals, self-trusting attitude for the regulation of eating, relaxed relationship with food and tendency to savour the food while eating. With this research, we introduce a common language to the field and we present a new theoretical framework that does justice not just to the full breadth of characteristics that are necessary for the internally regulated eating style but also to the associations between them and the potential mechanisms by which they contribute to this eating style.

The investigation of diet recovery after distal gastrectomy

This study aims to investigate the adaptation process of the alimentary tract after distal gastrectomy and understand the impact of remnant stomach volume (RSV) on diet recovery.One year after gastrectomy, although patients' oral intake had increased, the RSV was decreased and small bowel motility was enhanced. Patients with a larger RSV showed no additional benefits regarding nutritional outcomes.We prospectively enrolled patients who underwent distal gastrectomy with Billroth II reconstruction to treat gastric cancer at a tertiary hospital cancer center between September 2009 and February 2012. Demographic data, diet questionnaires, computed tomography (CT), and contrast fluoroscopy findings were collected. Patients were divided into 2 groups according to the RSV calculated using CT gastric volume measurements (large vs small). Dietary habits and nutritional status were compared between the groups.Seventy-eight patients were enrolled. Diet volume recovered to 90% of baseline by the 36 postoperative month, and RSV was 70% of baseline at 6 months after surgery and gradually decreased over time. One year after surgery, small bowel transit time was 75% compared to the 1st postoperative month (P < .05); however, transit time in the esophagus and remnant stomach showed no change in any studied interval. Compared to patients with a small RSV, those with a large RSV showed no differences in diet volume, habits, or other nutritional benefits (P > .05).Diet recovery for distal gastrectomy patients was achieved by increased small bowel motility. The size of the remnant stomach showed no positive impact on nutritional outcomes.

Glucagon-Like Peptides 1 and 2 Are Involved in Satiety Modulation After Modified Biliopancreatic Diversion: Results of a Pilot Study

BACKGROUND

This paper aimed to evaluate the influence of modified biliopancreatic diversion (BPD) on the levels of GLP-1 and GLP-2 and correlate them with satiety regulation.

METHODS

This is a pilot prospective cohort study that evaluated six mildly obese individuals with type 2 diabetes mellitus, which underwent modified BPD and were followed-up for 12 months. Levels of GLP-1 and GLP-2 after a standard meal tolerance test were determined and correlated with satiety scores obtained by means of a visual analogue scale (VAS).

RESULTS

There were significant changes in BMI (33 ± 2.2 versus 26.3 ± 2.2 kg/m²; p < 0.001), HbA1c (7.9 ± 1.6 versus 5.8 ± 1.2%; p = 0.026), total cholesterol (172.3 ± 11.1 versus 134.7 ± 16.1 mg/dL; p < 0.001), LDL-c (103.3 ± 13 versus 64.6 ± 12.2 mg/dL; p < 0.001), and postprandial GLP-2 (972.7 ± 326.2 versus 1993.2 ± 1024.7; p = 0. 044). None of the scores obtained in the VAS significantly changed after surgery. After surgery, there were significant correlations of VAS scores and GLP-1 levels in question 01 ("how hungry do you feel?"; R = -0.928; p = .008) and GLP-2 levels in questions 02 ("how full do you feel?" R = 0.943; p = 0.005) and 04 ("how much do you think you can eat now? R = -0.829; p = 0.042).

CONCLUSIONS

Modified BPD does not lead to significant changes in satiety evaluated by the VAS; different aspects of satiety regulation are correlated with the postprandial levels of GLP-1 (hunger feeling) and GLP-2 (satiation feeling and desire to eat) 1 year after modified BPD, signaling a specific postoperative gut hormone-related modulation of appetite.

Nutrient intake and contribution of home enteral nutrition to meeting nutritional requirements after oesophagectomy and total gastrectomy

BACKGROUND/OBJECTIVES

This study evaluated nutrition after oesophago-gastric resection and the influence of home jejunostomy feeding in the six months after surgery.

SUBJECTS/METHODS

Data on nutritional intake and physiologic measures were collected as part of a randomised trial with measurements taken before and up to six months after surgery.

RESULTS

A total of 41 participants (32 oesophagectomy, 9 total gastrectomy) received home jejunostomy feeding (n=18) or usual care without feeding (n=23). At hospital discharge, oral intakes were adequate for energy and protein in 9% and 6%, respectively. By three and six months, these values had increased to 61% and 55%, 94% and 77% respectively. Six participants (26%) who received usual care required rescue feeding. Six weeks after hospital discharge, energy intakes were met in those who received jejunal feeding because of the contribution of enteral nutrition. Jejunal feeding did not affect oral intake, being similar in both groups (fed: 77% estimated need, usual care: 79%). At three months, inadequate micronutrient intakes were seen in over one third. Compared to baseline values, six weeks after surgery, weight loss exceeding 5% was seen in 5/18 (28%) who received feeding, 14/17 (82%) who received usual care and 5/6 (83%) of those who required rescue feeding, P=0.002. Weight loss averaged 4.1% (fed), 10.4% (usual care) and 9.2% (rescue fed), P=0.004. These trends persisted out to six months.

CONCLUSIONS

Supplementary jejunostomy feeding made an important contribution to meeting nutrition after oesophago-gastric resection. Importantly, oral nutritional intake was not compromised dispelling the assertion that jejunal feeding deincentivises patients from eating.

Physiology, pathophysiology and therapeutic implications of enteroendocrine control of food intake

With the increasing prevalence of obesity and its associated comorbidities, strides to improve treatment strategies have enhanced our understanding of the function of the gut in the regulation of food intake. The most successful intervention for obesity to date, bariatric surgery effectively manipulates enteroendocrine physiology to enhance satiety and reduce hunger. Areas covered: In the present article, we provide a detailed overview of the physiology of enteroendocrine control of food intake, and discuss its pathophysiologic correlates and therapeutic implications in both obesity and gastrointestinal disease. Expert commentary: Ongoing research in the field of nutrient sensing by L-cells, as well as understanding the role of the microbiome and bile acid signaling may facilitate the development of novel strategies to combat the rising population health threat associated with obesity. Further refinement of post-prandial satiety gut hormone based therapies, including the development of chimeric peptides exploiting the pleiotropic nature of the gut hormone response, and identification of novel methods of delivery may hold the key to optimization of therapeutic modulation of gut hormone physiology in obesity.

**-Postprandial pancreatic [11C]methionine uptake after pancreaticoduodenectomy mirrors basal beta cell function and insulin release

Purpose

[S-methyl-¹¹C]-L-methionine ([¹¹C]MET) uptake in the pancreas might be a central indicator of beta cell function. Since gastric emptying was recently shown to influence glycemic control in subjects after pancreaticoduodenectomy (PD, the surgical treatment of neoplasms of the pancreas head), we looked for imaginable relationships between gastric emptying, pre- and postprandial insulin concentrations, and [¹¹C]MET uptake.

Methods

Nineteen tumor-free survivors after PD (age mean ± SD: 61 ± 8.7 yrs.; 10 male, 9 female) and 10 healthy controls (age: 27 ± 8.7 yrs.; 7 male, 3 female) were given a mixed test meal. One gram of paracetamol was ingested with the meal to evaluate the speed of gastric emptying. Insulin, glucose, and paracetamol plasma concentrations were measured before and over 180 minutes after ingestion. Beta cell function was calculated from fasting glucose and insulin plasma concentrations. Simultaneously, 800 MBq of [¹¹C]MET were administered and the activity (maximum tissue standardized uptake values [SUVmax]) over the pancreas was measured at 15, 30, and 60 minutes after injection. Total integrated SUVmax (area under the curve [AUC]) and incremental SUVmax were calculated.

Results

The uptake of [¹¹C]MET in the pancreas was significantly higher (p < 0.0001) in controls compared to the PD group. Gastric emptying was significantly slower in controls compared to pancreatectomy subjects (p < 0.0001). Paracetamol AUC₃₀ correlated with the SUVmax increment between 15 and 30 minutes (R² = 0.27, p = 0.0263), suggesting a relationship between gastric emptying and the uptake of [¹¹C]MET. Total integrated SUVmax correlated with insulin AUC₆₀ (R² = 0.66,p < 0.0001) in patients after PD. Multivariate regression analysis revealed insulin AUC₆₀ and beta cell function, calculated from the fasting insulin to glucose ratio, as independent predictors of ¹¹C-methionine uptake, i.e. total integrated SUVmax, in patients after PD (R² = 0.78, p < 0.0001).

Conclusion

Postprandial [¹¹C]MET uptake may represent basal and postprandial beta cell function. The findings suggest a possible usefulness of this imaging procedure for further studying beta cell function.

Function of ghrelin and ghrelin receptors in the network regulation of gastric motility

Numerous previous studies have demonstrated that ghrelin promotes gastric motility when administered peripherally. This effect appears to be regulatory but not directly stimulatory, and therefore may involve a number of complex mechanisms. In the periphery, ghrelin may affect gastric motility through intercellular networks among interstitial cells of Cajal, myenteric nerve cells and smooth muscle cells. The aim of the present study was to investigate the effects and possible mechanisms underlying this hypothesis. The effects of ghrelin on the contraction force of gastric antrum smooth muscle strips of rats were studied in the presence or absence of carbachol (CCh), [D‑Lys3]‑GHRP‑6, atropine, tetrodotoxin (TTX) and nimodipine in vitro. The expression of ghrelin receptors (GHS‑Rs) on different cell types in gastric muscle layers was observed by means of immunofluorescence. Ghrelin enhanced smooth muscle strip contraction induced by CCh, but when CCh was absent, this effect was eliminated. Atropine and nimodipine eradicated the muscle strip contraction enhanced by ghrelin, while [D‑Lys3]‑GHRP‑6 was only able to partly block this effect and TTX had no effect on muscle strip contraction. It was identified that ghrelin had no effect on the contractive rhythm of the strips. GHS‑R1s were located differentially depending on the cell type, including myenteric nerve cells, interstitial cells of Cajal and smooth muscle cells. In conclusion the present study demonstrated that ghrelin may act as an adjuvant to regulate gastric smooth muscle contraction induced by CCh through GHS‑R1s, which are expressed on myenteric nerve cells, Cajal cells and smooth muscle cells. Ghrelin may exert its effects by influencing the functional status of different cell types in the gastric muscle layer to subsequently enhance the contractive effect of cholinergic neurotransmitters and enhance gastric motility.

Clinical application of ghrelin administration for gastric cancer patients undergoing gastrectomy

Loss of body weight is a common (and the most serious) sequela after gastrectomy. It impairs quality of life, increases various diseases including infection, and may affect long-term survival. Ghrelin, an intrinsic ligand of the growth hormone secretagogue receptor, was discovered in the stomach in 1999. In addition to growth hormone secretion, ghrelin has pleiotropic functions including appetite stimulation, increasing bowel movement and absorption, and anti-inflammatory reactions. In consequence, ghrelin comprehensively leads positive energy balance and weight gain. The fundic gland of the stomach produces the majority of ghrelin, and plasma ghrelin declines to 10-30 % of the preoperative level after total gastrectomy and 50-70 % after distal gastrectomy. Although plasma ghrelin is never restored after total gastrectomy, it gradually recovers to the preoperative level within a few years after distal gastrectomy. Chronic gastritis due to Helicobacter pylori infection and vagotomy are additional factors that perturb the ghrelin secretion of gastric cancer patients after gastrectomy. A randomized clinical trial that revealed that recombinant ghrelin administration successfully increased both food intake and appetite, and ameliorated weight loss after total gastrectomy. Ghrelin administration could thus be a promising strategy to transiently improve the nutritional status of patients who who have undergone gastrectomy, but its effect in the long term remains unclear. Further studies are warranted to elucidate the mechanism of ghrelin and to create and evaluate the analogs that could be administered orally or subcutaneously.

Gastric motility in ghrelin receptor knockout mice

The aim of this study was to investigate the effects and possible mechanisms of ghrelin receptor (GHS-R) deficiency on gastric motility in GHS-R deficient (Ghsr-/-) mice. Ghsr-/- and control (Ghsr+/+) mice were genotyped by PCR. The percentage of gastric emptying (GE%) was calculated following the intraperitoneal adminis-tration of ghrelin. In vitro, the contractile response of smooth muscle strips to ghrelin and electrical field stimulation (EFS) and the intraluminal pressure change of isolated stomach to carbachol were observed in an organ bath. The staining of nerve cells in the gastric muscle layer was performed by immunofluorescence. Delayed gastric emptying was observed in the Ghsr-/- mice; ghrelin enhanced the GE% in the Ghsr+/+ mice but had no effect on the GE% in the Ghsr-/- mice. In vitro, the response of the strips to ghrelin and EFS and the intraluminal pressure change to cabarchol was reduced in the Ghsr-/- mice. GHS-Rs were predominantly expressed on nerve cells in gastric muscle layers. The number of nerve cells was observed to be decreased in the Ghsr-/- mice. The delayed gastric emptying may relate to the loss of GHS-Rs and the reduction in the number of nerve cells in the gastric muscle layers of the GHS-R-deficient mice.

Postprandial proximal gastric acid pocket and gastric pressure in patients after gastric surgery

BACKGROUND

An unbuffered postprandial proximal gastric acid pocket (PPGAP) has been demonstrated in normal individuals (NI) and patients with gastro-esophageal reflux disease (GERD). The role of gastric anatomy and gastric motility in the physiology of the PPGAP remains elusive. This study aims to analyze the correlation of PPGAP with proximal gastric pressure after gastric surgery.

METHODS

A total of 26 individuals were studied: eight patients after open Roux-en-Y gastric bypass (RYGB) for morbid obesity, six patients after laparoscopic Nissen fundoplication for GERD, seven patients after open subtotal gastrectomy for gastric cancer and five NI. Patients underwent high resolution manometry to identify the location of the lower border of the lower esophageal sphincter (LBLES) and measure gastric pressure 1, 2, 3, 4 and 5 cm below the LBLES, immediately before swallow and after the end of the LES relaxation. A station pull-through pH monitoring was performed in all but NI, from 5 cm below the LBLES to the LBLES in increments of 1 cm in a fasting state and 10 min after a standardized fatty meal.

KEY RESULTS

Our results show that: (i) proximal gastric pressures are lower after swallow compared with before swallow in NI; (ii) patients after gastric surgery tend to have higher gastric pressure before and lower after swallow compared with NI and (iii) patients after RYGB with PPGAP have an increased gastric pressure after swallows in the segment where the PPGAP is noticed.

CONCLUSIONS & INFERENCES

Gastric motility may play a role in the genesis of PPGAP in patients after RYGB. The contribution of gastric motility for the genesis of PPGAP is still elusive in other patients.

Fast-track surgery improves postoperative recovery in patients with gastric cancer: a randomized comparison with conventional postoperative care

BACKGROUND

Fast-track surgery is a new, promising comprehensive program for surgical patients and is beneficial to recovery. Prospective randomized, controlled clinical trials involving fast-track surgery for gastric cancer are lacking.

PATIENT AND METHODS

Ninety-two patients with gastric cancer were randomly divided into a fast-track surgery group (n = 45) and conventional surgery group (n = 47). We compared outcomes (duration of postoperative stay in hospital, fever, and flatus, complications, and medical costs); postoperative serum levels of tumor necrosis factor-alpha, interleukin-6, and C-reactive protein; and resting energy expenditure between two groups.

RESULTS

Compared with the conventional surgery group, the fast-track surgery group had no more complications (P > 0.05) with a significantly shorter duration of fever, flatus, and hospital stay, and less medical costs as well as a higher quality of life score on hospital discharge (all P < 0.05). With a significantly lower resting energy expenditure (days 1 and 3) postoperatively (P < 0.05), the fast-track surgery group showed a lower serum level of tumor necrosis factor-alpha (days 1 and 3), interleukin-6 (days 1 and 3), and C-reactive protein (days 1, 3, and 7) than the conventional surgery group (all P < 0.05).

CONCLUSIONS

Fast-track surgery can lessen postoperative stress reactions and accelerate rehabilitation for patients with gastric cancer.

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

BACKGROUND

Published data on sleeve gastrectomy (SG) have indicated better remission of type 2 diabetes mellitus (T2DM) and improvement in satiety compared with other restrictive procedures. Mechanisms in addition to rapid, extensive weight loss are responsible for the restoration of the euglycemic state. To prospectively evaluate the role of laparoscopic SG on gastric emptying half-time and small bowel transit time (SBTT) and effect of these on weight loss, satiety, and improvement in T2DM.

METHODS

A total of 67 subjects were studied. Of these 67 subjects, 24 were lean controls (body mass index 22.2 +/- 2.84 kg/m(2)), 20 were severely and morbidly obese patients with T2DM who had not undergone SG (body mass index 37.73 +/- 5.35 kg/m(2)), and 23 were severely and morbidly obese patients with T2DM after SG (body mass index 40.71 +/- 6.59 kg/m(2)). All 67 patients were evaluated for gastric emptying half-time and SBTT using scintigraphic imaging. Imaging was performed every 15 minutes up to the ileocecal region. The Three-Factor Eating Questionnaire was administered simultaneously. Fasting blood sugar, postprandial blood sugar, and glycated hemoglobin were assessed. Nonparametric analysis of variance and the Mann-Whitney U test were applied.

RESULTS

The mean SBTT was significantly lower (P <.05) in the post-SG group (199 +/- 65.7 minutes) than in the non-SG group (281.5 +/- 46.2 minutes) or control group (298.1 +/- 9.2 minutes). The gastric emptying half-time values were also significantly shorter (P <.05) in the post-SG (52.8 +/- 13.5 minutes) than in the non-SG (73.7 +/- 29.0 minutes) and control (72.8 +/- 29.6 minutes) groups. The glycated hemoglobin, fasting blood sugar, and postprandial sugar were all significantly lower after SG. The Three-Factor Eating Questionnaire findings revealed significantly earlier satiety (29.0 +/- 7.2) for the post-SG patients (P <.05) compared with the non-SG (45.8 +/- 9.0) and control (37.9 +/- 6.2) subjects.

CONCLUSION

A decreased gastric emptying half-time and SBTT after SG can possibly contribute to better glucose homeostasis in patients with T2DM.