Dietary Carbohydrate and GERD in Veterans (DietGERD)

4-Arm Diet Intervention Investigating Effects of Dietary Carbohydrate Type and Amount on gastroesophageal pH, gastroesophageal reflux disease (GERD) symptoms and medication use.

delayed due to COVID related research shutdown Specific Hypothesis: The preliminary findings suggest a physiological mechanism between dietary intake and GERD that may be related to type of dietary carbohydrate intake (complex vs simple carbohydrate). The investigators hypothesize that modifying the type of dietary carbohydrate consumed - by reducing the proportion of simple carbohydrate (sugars) consumed - will reduce or resolve GERD symptoms and medication use in obese Veterans with chronic GERD. The investigators further hypothesize that the mechanistic effects of reducing simple carbohydrate intake is related to either: a) improved dietary fiber intake and/or glycemic load, and thus, reduced amount and duration of esophageal acid exposure; and/or b) improved insulin sensitivity which would positively influence the function of key gastrointestinal hormones (ie, gastrin, glucagon, GLP-1, ghrelin11) that regulate gastric motility and/or lower esophageal sphincter function. Aim 1: To determine effects of dietary carbohydrate consumed (amount and type) on percent time with esophageal pH < 4.0, as well as number of reflux episodes, GERD symptoms and GERD medication use, in 200 obese Veterans who have chronic high frequency of GERD symptoms. To meet this aim the investigators will use a randomized controlled trial in which the investigators manipulate amount of total and simple dietary carbohydrate intake for duration of 9 weeks. Aim 2: To assess associations between GERD resolution variables and factors related to potential mechanisms by which modifying dietary carbohydrate intake could resolve/reduce GERD in obese Veterans. 2a: The investigators will investigate associations related to whether the effect is nutritionally mediated by measuring change in dietary fiber load and dietary glycemic load, and thus, whether these changes are related to improved gastric acid secretion (% time pH < 4), gastric motility, and/or the other parameters that comprise the Johnson-DeMeester score. 2b: The investigators will also investigate whether effects are associated with changes in the hormonal milieu by measuring hormonal response of gastrin, glucagon, glucagon-like peptide-1 (GLP-1), ghrelin and insulin, which could potentially influence gastric acid secretion, gastric motility and/or lower esophageal sphincter function.

GERD symptoms measured weekly for 9 weeks using Gastroesophageal Reflux Disease Symptom Assessment Scale (GSAS)

GERD symptoms measured weekly for 9 weeks using Gastroesophageal Reflux Disease Questionnaire (GERDQ)

Inclusion Criteria: Age 21 or over BMI 30-39.9 GERD Exclusion Criteria: History of type 1 diabetes Hernia or strictures Gastroparesis Extra-esophageal GERD Barrett's esophagus or Esophageal adenocarcinoma History of gastric or bariatric or esophageal surgery, radiation or cancer History of gastrointestinal malabsorption Alcohol averaging > 2 drinks per day during past 3 months Pregnancy / Lactation

Gu C, Olszewski T, King KL, Vaezi MF, Niswender KD, Silver HJ. The Effects of Modifying Amount and Type of Dietary Carbohydrate on Esophageal Acid Exposure Time and Esophageal Reflux Symptoms: A Randomized Controlled Trial. Am J Gastroenterol. 2022 Oct 1;117(10):1655-1667. doi: 10.14309/ajg.0000000000001889. Epub 2022 Jun 21.