In the previous article, we went over how decreasing stomach acidity might not be the best choice for heartburn or GERD. In this article we are going to go over the mechanisms of how stomach acid prevents GERD and how it is actually needed for healthy gut function.
Producing stomach acid is one of the first major steps in proper digestion.
To understand how/why more stomach acid is good for you (and how it prevents heartburn or GERD) we must first understand the very basics of digestion. The ability of our body to be able to breakdown food into small particles that we can absorb is the definition of digestion. Now there are a lot of steps involved. For the sake of not boring you we will only go over the basics. Much of digestion is heavily dependent on stomach acid production. The pH of hydrochloric acid as it leaves the acid producing cells in the stomach is around 0.8. This is comparable to the pH of battery acid. As the acid moves away from the proximity of the stomach cells the acid becomes more dilute, but still is very acidic at a pH of around 1.5-3.0. This pH is crucial to be able to activate certain protein digesting enzymes to help breakdown our food quickly and send the broken down food into the small intestine where we can begin to break it down further and absorb the nutrients.
So if the acid in our stomach helps break down our food quickly, when we have low stomach acidity do you think the food in our stomach will sit there for a longer period of time or a shorter period of time? A longer period of time! And if our food sits in our stomach for a longer period of time are the odds of the food coming back up into the esophagus greater or less? Greater! This is one of the reasons why people with low stomach acidity experience more symptoms of heartburn or GERD as well as feeling bloated/full after meals.
Lower Esophageal Sphincter Tone and Stomach Acidity
The lower esophageal sphincter is essentially a ring like muscles that acts as a gate that should be sealed shut unless swallowing food or burping up air. When it comes to heartburn or GERD what it boils down to is how well the lower esophageal sphincter can separate the contents from the stomach from the esophagus. The lower esophageal sphincter responds to 3 different types of stimuli (1): distension, chemical stimuli, and temperature. It has been known for decades now that lower esophageal sphincter contraction responds heavily to pH. One study found that the lower the pH (more acidic) the contents of the stomach got, the more pressure the lower esophageal sphincter responded with (2).
ON THE RELATIONSHIP BETWEEN GASTRIC PH AND PRESSURE IN THE NORMAL HUMAN LOWER OESOPHAGEAL SPHINCTER.
“…exposure of the cardia and of the distal portion of the gastro-oesophageal junctional zone to solutions of low pH has a significant influence upon the resting pressures recorded from the lower oesophageal sphincter.”
– Gut – M D Kaye
The same study found no increase in lower esophageal sphincter pressure with saline or distilled water solution. This suggests that over time a healthy stomach (with enough stomach acidity) should equate to healthy lower esophageal sphincter tone. Like a muscle, if the lower esophageal sphincter isn’t exposed to what makes it contract (like stomach acidity), it may become and less toned. As mentioned before, a weaker lower esophageal sphincter is ultimately what causes heartburn or GERD.
Stomach Acid Sets the Tone for a Healthy Gut
Besides lysozyme in our saliva, one of our first lines of defense from the bacteria we ingest is stomach acid. If you read the previous article, you know that one risk factor of having lower stomach acidity is an increased risk for infection. Besides killing bacteria, we need stomach acid to increase the potency of certain enzymes. This includes turning pepsinogen into pepsin, which helps break down your proteins (3). Stomach acid and the pH of the food coming out of the stomach is a huge trigger for the release of certain hormones called Secretin and Cholecystokinin (CCK) (4). Secretin helps the release of pancreatic enzymes to further break down food. These pancreatic enzymes are also potent antimicrobials. Secretin also helps the release of massive amounts of bicarbonate to regulate gastrointestinal pH and encourage the growth of healthy bacteria. CCK helps with the contraction of the gallbladder to release bile into our small intestine. Bile helps us absorb fats and fat soluble vitamins. It is also a potent antimicrobial (5). In both animal and human models, when the flow of bile is altered it is associated with both an overgrowth of bacteria in the intestines as well as contributes towards leaky gut/mucosal injury. Certain cells of the small intestine (Paneth cells) secrete further antimicrobial substances such as B-defensins, lysozyme, and type 2 phospholipase A (6,7). With mucosal injury, these antimicrobial enzymes may not function optimally allowing overgrowth of bacteria. With mucosal injury/leaky gut this bacteria can cross the gut barrier and lead to systemic infection (8,9). In animal models, all of the negative effects that bile obstruction has on the gut can be reversed by supplementing with bile acids (9). This is unfortunate because what do most people turn to when dealing with gastrointestinal symptoms? Anti-acids and proton pump inhibitors which in the long term can further exacerbate symptoms like fatigue, depression, aches and pains, bloating/gas, constipation or diarrhea. The only gut related symptom in can help is heartburn. But at what cost?
The Downward Spiral of Decreased Stomach Acidity
How do you stop the vicious cycle?
Heartburn typically poses no immediate emergency on people, so I recommend finding a functionally oriented practitioner who can help you with an enzyme regimen to help break the cycle. One of the first steps to this is making sure your body has adequate enzymes starting with hydrochloric acid for the stomach.
