Contents


Preface

Gastroesophageal reflux disease (GERD) is the most common digestive disorder worldwide. Despite efforts made over the years in GERD treatment and prevention, GERD incidence is still growing steadily. According to the latest report, GERD increased by 77.53% globally during 1990–2019, from 440 million to 780 million. Most of the cases came from India and China, the two most populated countries, accounting for 180 million and 80 million cases, respectively. Due to the lack of a unifying standard for diagnosis, the actual number of GERD sufferers is likely much higher. Based on a recent meta-analysis, GERD potentially affects 0.9–1.1 billion people worldwide, which is about 14% of the current global population. The impact of GERD on word health and economy is great. In Europe, for example, GERD caused a 26% reduction in productivity, costing employers

GERD mainly affects two organs: the esophagus and the stomach. Although these two organs are neighboring parts of the digestive tract and both are involved in transporting food from the mouth to the intestine for digestion and absorption, they constitute a one-way street. Food can only go from the esophagus to the stomach, otherwise, it will cause damage to the epithelial lining of the esophagus because the ingested food becomes highly acidic once reaching the stomach. The squamous epithelium in the esophagus is not made to stand such a highly acidic condition and, as a result, esophagitis develops. When these reflux episodes take place again and again, the esophageal lining gradually changes from squamous to columnar, becoming the intestinal-like phenotype, which is called Barrett's Esophagus. When this happens, the patient is 400

The lower esophageal sphincter (LES) is a muscular structure sitting between the esophagus and the stomach that prevents the stomach content from going into the esophagus. Therefore, anything that interrupts LES function is a potential cause of GERD. Obesity or overweight is the number one factor. The excessive weight in the abdominal region puts constant pressure on the stomach, forcing the stomach content to break the LES barrier and erupt into the esophagus, causing esophagitis. Other factors include eating habits, lifestyle, taking certain drugs, esophageal or gastric motility weakness, and so on. Some common food and drinks (e.g., coffee, tea, soda, juices, alcoholic beverages, chocolates, tomatoes, high-fat or high-calorie food, or spicy food) can create occasional GERD episodes in healthy individuals or worsen the condition of GERD patients. Many medications can also interfere with the LES function and result in GERD symptoms, such as nitrates, calcium channel blockers, anticholinergic drugs, benzodiazepines, nitroglycerin, albuterol, antidepressants,

glucagon, and non-steroidal anti-inflammatory drugs (NSAIDs).

For these reasons, the current strategies for GERD management and prevention mainly rely on changing eating habits, modifying lifestyle, suppressing gastric acid secretion, and surgically restoring LES function. However, none of these have

approximately 4.4 billion dollars in 2018.

times more likely to develop esophageal cancer.
