Reflux is a condition caused by relaxation of the lower esophageal sphincter or muscle that causes a one way valve meant to keep stomach contents going one way and not regurgitating backwards into the esophagus.
GERD occurs when the contents, especially acid, of the stomach back up into the esophagus, leading to symptoms or lesions of the esophageal mucosa.
Meal intake affects esophagogastric physiology in several ways: It reduces the tone of the lower esophageal sphincter (LES) and increases the number of transient LES relaxations (TLESRs), which are induced by distension and relaxation of the proximal stomach. These effects are mediated by vagal afferent stimulation and the stretching of the mechanoreceptors of the fundic wall. They are influenced by neuropeptide effects such as cholecystokinin (CCK), which is released in the presence of lipids in the duodenal lumen. Hence the importance of caloric intake and lipid content, even though it is difficult to distinguish their respective effects. [1]
A high-calorie meal slows gastric emptying, thus prolonging gastric distension, reducing LES tone, and promoting the onset of TLESRs. Several studies have emphasized that at equivalent caloric intake, lipid composition has no impact on LES tone and the number of TLESRs in healthy patients or those with GERD. However, with equivalent caloric intake, and thus equivalent acid exposure, the presence of lipids in the meal increases the perception of reflux. This "reflux hypersensitivity" effect induced by lipids is caused by the endogenous release of CCK and its action on vagal afferents. This effect also is observed in the perception of functional dyspepsia symptoms. [1]
Several studies have evaluated low-carbohydrate diets in GERD. A small study of eight patients with morbid obesity on a very low–carbohydrate diet observed benefits on symptoms and esophageal acid exposure in pH probe testing. [1]
A randomized French study of 31 patients with refractory GERD found no significant difference between a low fermentable oligo-, di-, monosaccharides, and polyols diet and usual dietary advice.[1]
A recent American study of 95 veterans found an improvement in pH in the group reducing simple sugars but symptomatic improvement in all groups reducing sugar consumption in general.[1]
Therefore, based on all these data, according to Zerbib, "high-calorie meals, rich in fats or carbohydrates, promote the onset of reflux episodes and their perception. Diets low in fats and carbohydrates should be recommended." [1]
Obesity contributes to GERD by promoting increased abdominal pressure and constraints on the esophagogastric junction. A high-resolution manometry study provided robust evidence for this mechanism. Generally, the relative risk for symptomatic GERD with obesity is 2-3 compared with normal body mass index (BMI), with a linear increase according to BMI.[1]
(from N. Raffier, Medscape news)
[1] N Raffier. How Does Diet Affect Gastroesophageal Reflux Disease? Medscape Medical News. 4/1/2024 Medscape
