The effects of intraduodenal nutrient infusion on serum CCK, LES pressure, and gastroesophageal reflux

Causal association between dietary factors and esophageal diseases: A Mendelian randomization study

BACKGROUND

Using Mendelian randomization (MR) approach, our objective was to determine whether there was a causal association between dietary factors and gastroesophageal reflux disease (GERD), Barrett's esophagus (BE), or esophageal cancer (EC).

METHODS

Genome-wide association study (GWAS) data for eighteen types of dietary intake were obtained from the UK Biobank. GWAS data for GERD, BE, and EC were sourced from the FinnGen consortium. We performed univariable and multivariable MR analysis to assess the cause effect between dietary factors and esophageal diseases. MR results were expressed as odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

Raw vegetable intake was associated with a lower risk of GERD (OR = 0.478; P = 0.011). On the contrary, cooked vegetable intake increased the risk of GERD (OR = 1.911; P = 0.024). Bread intake was associated with increased odds of BE (OR = 6.754; P = 0.007), while processed meat intake was associated with reduced risk of BE (OR = 0.210; P = 0.035). We also observed evidence that increased consumption of dried fruit (OR = 0.087; P = 0.022) and salt added to food (OR = 0.346; P = 0.045) could prevent EC. The results of multivariable MR showed that the protective effect of consumption of salt added to food on EC was no longer significant after adjusting for the consumption of dried fruit.

CONCLUSION

Vegetable consumption was associated with GERD, whereas consumption of bread and processed meat was associated with BE. Dried fruit intake was associated with a lower risk of EC, and the protective effect of consumption of salt added food on EC may also be mediated by consumption of dried fruit. Future research should be performed to investigate the mechanisms behind these cause-and-effect relationships to reduce the burden of disease caused by dietary habits.

Food and Gastroesophageal Reflux Disease

Gastroesophageal reflux disease is a chronic condition with a high prevalence in western countries. Transient lower esophageal sphincter relaxation episodes and a decreased lower esophageal sphincter pressure are the main mechanisms involved. Currently used drugs are efficient on reflux symptoms, but only as long as they are administered, because they do not modify the reflux barrier. Certain nutrients or foods are generally considered to increase the frequency of gastroesophageal reflux symptoms, therefore physicians recommend changes in diet and some patients avoid bothering foods. This review summarizes current knowledge regarding food and gastroesophageal reflux. For example, fat intake increases the perception of reflux symptoms. Regular coffee and chocolate induce gastroesophageal reflux and increase the lower esophageal exposure to acid. Spicy foods might induce heartburn, but the exact mechanism is not known. Beer and wine induce gastroesophageal reflux, mainly in the first hour after intake. For other foods, like fried food or carbonated beverages data on gastroesophageal reflux is scarce. Similarly, there are few data about the type of diet and gastroesophageal reflux. Mediterranean diet and a very low carbohydrate diet protect against reflux. Regarding diet-related practices, consistent data showed that a "short-meal-to-sleep interval" favors reflux episodes, therefore some authors recommend that dinner should be at least four hours before bedtime. All these recommendations should consider patient's weight, because several meta-analyses showed a positive association between increased body mass index and gastroesophageal reflux disease.

How Satiating Are the 'Satiety' Peptides: A Problem of Pharmacology versus Physiology in the Development of Novel Foods for Regulation of Food Intake

Developing novel foods to suppress energy intake and promote negative energy balance and weight loss has been a long-term but commonly unsuccessful challenge. Targeting regulation of appetite is of interest to public health researchers and industry in the quest to develop ‘functional’ foods, but poor understanding of the underpinning mechanisms regulating food intake has hampered progress. The gastrointestinal (GI) or ‘satiety’ peptides including cholecystokinin (CCK), glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) secreted following a meal, have long been purported as predictive biomarkers of appetite response, including food intake. Whilst peptide infusion drives a clear change in hunger/fullness and eating behaviour, inducing GI-peptide secretion through diet may not, possibly due to modest effects of single meals on peptide levels. We conducted a review of 70 dietary preload (DIET) and peptide infusion (INFUSION) studies in lean healthy adults that reported outcomes of CCK, GLP-1 and PYY. DIET studies were acute preload interventions. INFUSION studies showed that minimum increase required to suppress ad libitum energy intake for CCK, GLP-1 and PYY was 3.6-, 4.0- and 3.1-fold, respectively, achieved through DIET in only 29%, 0% and 8% of interventions. Whether circulating ‘thresholds’ of peptide concentration likely required for behavioural change can be achieved through diet is questionable. As yet, no individual or group of peptides can be measured in blood to reliably predict feelings of hunger and food intake. Developing foods that successfully target enhanced secretion of GI-origin ‘satiety’ peptides for weight loss remains a significant challenge.

Increased nutrient sensitivity and plasma concentrations of enteral hormones during duodenal nutrient infusion in functional dyspepsia

OBJECTIVES

Functional dyspepsia is predominantly attributed to gastric sensorimotor dysfunctions. The contribution of intestinal chemosensitivity to symptoms is not understood. We evaluated symptoms and plasma hormones during enteral nutrient infusion and the association with impaired glucose tolerance and quality-of-life (QOL) scores in patients with functional dyspepsia vs. healthy controls.

METHODS

Enteral hormonal responses and symptoms were measured during isocaloric and isovolumic dextrose and lipid infusions into the duodenum in 30 patients with functional dyspepsia (n=27) or nausea and vomiting (n=3) and 35 healthy controls. Infusions were administered in randomized order over 120 min each, with a 120-min washout. Cholecystokinin, glucose-dependent insulinotropic peptide, glucagon-like peptide 1 (GLP1), and peptide YY were measured during infusions.

RESULTS

Moderate or more severe symptoms during lipid (4 controls vs. 14 patients) and dextrose (1 control vs. 12 patients) infusions were more prevalent in patients than controls (P≤0.01), associated with higher dyspepsia symptom score (P=0.01), worse QOL (P=0.01), and greater plasma hormone concentrations (e.g., GLP1 during lipid infusion). Moderate or more severe symptoms during enteral infusion explained 18%, and depression score explained 21%, of interpatient variation in QOL. Eight patients had impaired glucose tolerance, associated with greater plasma GLP1 and peptide YY concentrations during dextrose and lipid infusions, respectively.

CONCLUSIONS

Increased sensitivity to enteral dextrose and lipid infusions was associated with greater plasma enteral hormone concentrations, more severe daily symptoms, and worse QOL in functional dyspepsia. These observations are consistent with the hypothesis that enteral hormones mediate increased intestinal sensitivity to nutrients in functional dyspepsia.

Nonalcoholic fatty liver disease increases risk for gastroesophageal reflux symptoms

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is now recognized as a leading cause of liver dysfunction. Gastroesophageal reflux disease (GERD) is a common disorder causing symptoms that often impair patients' quality of life. In recent years, the prevalence of both these diseases has increased, partially overlapping the rise of metabolic disorders.

AIMS

We investigated whether a relation does exist between NAFLD and GERD symptoms.

METHODS

Cross-sectional study among 206 outpatients diagnosed with NAFLD and 183 controls. We collected clinical and laboratory data, assessed severity and frequency of GERD symptoms and the esophageal endoscopic pattern.

RESULTS

The prevalence of GERD symptoms was higher in NAFLD patients than controls (61.2 vs. 27.9%, p < 0.001). We found a positive association between NAFLD and the experiencing of heartburn, regurgitation and belching. GERD symptoms were related to body mass index (BMI) and metabolic syndrome (MetS); a strong association persisted after adjustment for all the covariates (adjusted OR 3.49, 95 CI% 2.24-5.44, p < 0.001).

CONCLUSIONS

Our data show that the prevalence of GERD typical symptoms is higher in patients with NAFLD. GERD was associated with higher BMI and MetS, but not with age and diabetes type 2. NAFLD remained strongly associated with GERD, independently of a coexisting MetS status. Consistent with these findings, MetS can be considered a shared background, but cannot completely explain this correlation. We suggest NAFLD as an independent risk factor for GERD symptoms.

Dietary lipids and functional gastrointestinal disorders

There is convincing evidence that patients with functional gastrointestinal disorders (FGIDs) exhibit dysfunctions of the gut involving hypersensitivity and abnormal reflexes, so that physiological, normally unperceived, stimuli induce symptoms. The type of symptoms depends on the specific sensory-reflex pathways and region(s) affected. Fat modulates the responses of the gut to various stimuli, and some of these modulatory mechanisms are abnormal in patients with FGIDs. Indeed, laboratory-based studies have shown that the symptoms experienced by these patients can be induced, or exacerbated, by administration of lipids in amounts that are well tolerated by healthy controls, and, thus, demonstrate a hypersensitivity to lipid. Very few studies have evaluated dietary patterns and eating behavior in these patients, with often-conflicting outcomes, and no studies have been performed to evaluate the role of targeted dietary interventions for the relief of symptoms. Given the evidence from laboratory studies, as well as patient experience, such studies, in large cohorts of patients, are needed with the view to develop personalized, cost-effective treatment approaches.