One in five American adults experiences symptoms such as heartburn and belching caused by gastroesophageal reflux disease (GERD) every week; and an unlucky 60% of people get these GERD symptoms at least once a year. With GERD, stomach contents regurgitate back into the esophagus, leading to discomforts including bitter taste, abdominal pain, nausea, burning chest pain, belching, nausea, heartburn, and even dry cough. In addition to the hefty medical costs – $9 billion each year throughout the U.S. – GERD is also responsible for work productivity loss of $2 billion each week. Clearly, GERD is a serious and uncomfortable disease.
The first GERD Awareness Week, established by The International Foundation for Functional Gastrointestinal Disorders (IFFGD), started back in 1999. IFFGD chose the week surrounding Thanksgiving for GERD Awareness Week, which makes sense considering that GERD cases spike by 44% during the holiday season of Thanksgiving through New Year’s. The 17th annual GERD Awareness Week recently wrapped up, November 20-26, 2016, which makes this a fitting time for my upcoming blog series focused on the root causation of GERD, including the latest scientific understanding, current conventional treatments, complementary therapies to consider and growing concerns about complete acid blockade using the proton pump inhibitor (PPI) class of medications.
Symptoms of GERD
Chronic heartburn finds a place at the top of the list of GERD symptoms. However, numerous additional symptoms can also be experienced and considered “typical” of this condition. The long inventory of GERD discomforts include;
- acid regurgitation
- bad breath
- chest pain or discomfort
- chronic dry irritated sore throat
- dental erosions
- difficulty swallowing
- excessive clearing of the throat or salivation,
- erosion(s) of the dental enamel
- gingivitis, sour taste
- waterbrash (sudden excess saliva in the mouth)
Over time, there are a number of symptoms outside of the swallowing apparatus that have been linked to GERD and deemed “atypical,” such as asthma or asthma-like symptoms, chronic cough, hoarseness in the morning, laryngitis, sinus problems, sleep disturbances and more.
Pathophysiology of GERD
The main culprit, for most people experiencing GERD-related heartburn, is the reflux of stomach acid into the esophagus. However, stomach acid is not the only problem. This reflux can also bring up other stomach contents, such as bile and enzymes (pepsin and trypsin) which then degrade the esophageal lining. This esophageal lining damage, in turn, leads to the irritation of underlying nerve endings and painful sensations in the GERD sufferer.
The processes leading to the development of GERD can be quite complex, let’s unpack the key factors contributing to heartburn and other symptoms of GERD:
Numerous impairments in the movement of refluxed stomach contents out of the esophagus can lead to GERD. These can range from a failure in the sweeping mechanisms designed to clear the esophagus (aka esophageal motility) and reductions in salivary bicarbonate that should otherwise buffer acid reflux to deficits in esophageal lining integrity. In fact, current research into esophageal lining integrity is gaining momentum in the scientific literature as an unrecognized subtype of GERD. There are also newly uncovered concerns about the potential of reduced function of the lower esophageal sphincter that could play a role, since this sphincter – when functioning properly – should prevent regurgitation of stomach contents.
Interestingly, as stomach acid refluxes into the esophagus it paradoxically slows down esophageal motility. This slowed movement of stomach contents then increases acid levels, thus establishing a vicious cycle.
Cigarette smoking is a well-known risk factor for GERD as the nicotine relaxes the lower esophageal sphincter allowing more refluxed contents into the esophagus. Cigarette smokers have also been shown to have impairments in acid-clearance from the esophagus attributed to lower salivary bicarbonate production as well as increased production of stomach acid, this serves as a double whammy indeed.
Other mechanisms are likely in play as well. Salivary production is decreased during sleep which is one reason why prolonged esophageal acid clearance occurs during sleep, thus making it a high-risk time to experience heartburn. Gastroparesis, a condition characterized by the slowing of stomach emptying, allows for the pooling of gastric secretions and chyme, which is then more likely to reflux back into the esophagus. The pylorus sphincter, which separates the stomach from the small intestine, can play a role in GERD if it fails to function perfectly. A poorly functioning pylorus allows digestive juices and bile to flow backward into the stomach and, from there, back up the esophagus.
Esophageal lining barrier defense
There is a newer scientific concept gaining momentum in the current literature as a major contributor to GERD: esophageal lining barrier defense. Cells lining the esophagus should maintain a tight interlocking band that is impermeable to penetration. However, in GERD, the spaces between esophageal lining cells become widened by harmful agents or as the result of inflammation. When this happens, hydrogen ions are then able to escape into the space underneath the lining, which is where pain nerve fibers are stimulated. Ouch! What is fascinating is that most individuals with GERD appear to have normal esophageal lining when examined with conventional endoscopy, yet with more detailed analysis, these cells show evidence of microscopic defects.
Dysfunction of muscular sphincters
The improper function of muscular sphincters which regulate esophageal emptying are a key feature (and culprit) of GERD. The lower esophageal sphincter (LES) is a 2-3 cm long segment zone of smooth muscle that contracts while at rest. It regulates the passage of ingested contents into the stomach while preventing the regurgitation of these stomach contents. Patients with GERD rarely have a problem with a lowered resting LES pressure, but some people do experience that the relaxation phase that is supposed to be transient becomes prolonged and excessive. This is known as transient lower esophageal relaxation (TLER). Factors that contribute to LES dysfunction include medications (i.e., antidepressants, anticholinergics, asthma medications, blood pressure medications, hormone replacement therapy, nitrates, narcotics and others), distention of the stomach, alcohol, caffeine, chocolate, cigarette smoking, fatty meals, peppermint, tomatoes and much more.
In addition to the LES being tonically contracted, a normally-functioning diaphragm forms a pinch mechanism that serves as static protection against the regurgitation of stomach contents. When someone has a hiatal hernia, in which there is a slippage of the stomach through the weakened diaphragmatic pinch, it is possible to end up with an acid pocket sitting in the hernia sac with a resulting increased propensity for TLERs and reflux into the esophagus. Those with hiatal hernia could experience a pressure gradient changing from positive intraabdominal pressure to negative chest pressures that also promotes GERD in the setting of TSLERs. Abrupt rises in intraabdominal pressure can overcome disrupted diaphragmatic sphincters in the setting of a hiatal hernia and supersede tonic LES pressures, thus leading to GERD and its vast array of uncomfortable symptoms.
Esophageal Hypersensitivity or Visceral Hyperalgesia
It’s important to note that most patients with GERD do not have visible evidence of mucosal injury. In addition, most patients even have normal lower esophageal acid exposure. However, the key issue can often be a hypersensitivity to physiologic exposure to esophageal acid and, perhaps, a lower pain threshold to distension. Current research now suggests that there is a subtype of individuals who experience non-cardiac chest pain thought to be GERD. These individuals may actually be part of a spectrum of “functional gut disorders,” such as irritable bowel syndrome, functional dyspepsia and others. In this way, visceral hyperalgesia of the esophagus could be one of a spectrum of disorders characterized by dysregulation of pain-gate mechanisms and one solution could include techniques of pain modulation and mind-body therapies. This subtype of individual with “functional heartburn” could account for half of cases of endoscopy-negative reflux disease, which is better known as non-erosive reflux disease (NERD). As we will discuss in more depth in other blogs, many doctors treat NERD patients with functional heartburn with PPIs (proton pump inhibitors) despite a lack of data showing efficacy for this approach.
Risk Factors for GERD
Aside from the medications and foods mentioned earlier that can increase the experience of GERD, there are disease conditions that can make GERD more likely. These health conditions include obesity, diabetes, collagen vascular diseases such as scleroderma, states associated with immobility, dry mouth (xerostomia), pregnancy, gastroparesis, hiatal hernia and more. The most compelling data is that for obesity, with a direct correlation of intraabdominal girth (waist size) to risk of GERD. Fat cells also harbor inflammatory factors that, when released, may participate in the pathogenesis of GERD. The degree of body mass index (BMI) and waist circumference excess has consistently shown to be predictors of GERD prevalence and severity. Obesity is also a risk factor for the development of cancer as a consequence of chronic GERD.
GERD is the most common digestive health condition in the U.S. Adverse quality of life, frequent use of medications and long-term sequelae loom ahead for the untreated patient. Many factors can cause or provoke GERD, as well as contribute to the different subtypes of the disease. Given the variety of contributing causes, the management of GERD is best approached after an understanding of the core imbalances and remedy on a personalized basis. Over the next six weeks, the holidays present opportunities to celebrate life with family, friends and colleagues. Consider some helpful tips as shown in the figure from the IFFGD that can help you minimize discomfort during this holiday season. Time your meals properly, limit alcoholic drinks, eat lighter towards the evening, minimize citrus and acidic juices, watch portion size and choose baked over fried meats.
We will explore the management of GERD, along with concerns about the chronic use of PPIs, in subsequent blogs.
To Your Health,
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