Dropping Acid - The Truth About Stomach Acid

Have you been led to believe that too much stomach acid is causing your acid reflux or heartburn issues?  What if I told you that not having enough stomach acid may actually be the culprit for the burning/sour sensation you feel in your esophagus and more.

Understanding the Upper GI Tract Anatomy

Before we jump completely into stomach acid, let’s first review the anatomy of the GI tract. 

The GI tract is a long continuous tube that connects the upper and lower digestive organs starting with the mouth, esophagus, stomach, small intestine, colon, rectum, and anus.  The accessory organs involved in digestion include the teeth, tongue, salivary glands, pancreas, gallbladder, and liver.  

Between the esophagus and the stomach, there is a ring of muscle called the lower esophageal sphincter (LES ) that opens and closes to allow the passage of food and beverages from the esophagus to the stomach. Between the stomach and the first part of the small intestine is another ring of muscle called the pyloric sphincter. 

So how does digestion actually work?

Have you ever read been reading a menu or looked at a delicious plate of food and your mouth started watering?  That, my friend, is the beginning of digestion.  That “watering” process is actually the release of amylase enzymes that help to digest carbohydrates.  In the mouth, the act of chewing food thoroughly before swallowing helps to mechanically break down food.  

When the food enters the stomach it then encounters gastric juices and peristaltic waves of contractions that aid in digestion. Gastric juices are made up of digestive enzymes, hydrochloric acid, and other substances that are important for absorbing nutrients – about 3 to 4 liters of gastric juice are produced per day.¹ The chemical and mechanical process of digestion that occurs in the stomach breaks the food down into a ball of mush, also known as chyme. 

The pyloric sphincter opens and closes to allow the passage of the chyme between the stomach and small intestine.  When the chyme enters the small intestine, an alkaline substance is released from the pancreas to neutralize the chyme and digestive enzymes are released to further break down food.  Insulin and/or glucagon are released from the pancreas to regulate blood sugar and bile is released from the gallbladder to make fats more water-like.  Wave-like peristaltic contractions continue to move food along in the digestive tract with nutrient absorption taking place in the small intestine.

When food reaches the colon, the digestion process has been complete.  Water and the remaining nutrients are absorbed while beneficial bacteria ferment fibers which create short-chain fatty acids.  Any indigestible food, bacteria, toxins, dead mucosal cells, and hormones compose the stool that is eliminated from the body.

Digestion should be viewed as a north-to-south process. The events that happen at the beginning of digestion have a domino effect on the remaining processes. A disruption or inadequacy in any of those steps can affect all digestion and absorption events downstream.

Why is stomach acid important?

So let’s talk specifically about stomach acid, AKA hydrochloric acid or HCl.  HCl is produced by the parietal cells of the stomach.  The acidic environment of the stomach protects us from any pathogens that may be in the food and beverages that are ingested but it also plays a critical role in protein digestion.  Chief cells in the stomach release inactive pepsin, the main enzyme involved with protein digestion,  which becomes activated with hydrochloric acid.  It (pepsin) breaks down proteins into smaller peptides and amino acids that can be easily absorbed in the small intestine.²  Amino acids are the building blocks for things like hormones, immune cells, neurotransmitters, enzymes, and more!

In addition to stomach acid role of protecting us from pathogens and aiding in protein digestion, it also signals to your body to allow the passage of the chyme (the ball of mushed-up food) from your stomach to the small intestine.  The pH of that chyme actually needs to be between 1.5 and 3 in order for the pyloric sphincter to open to allow the chyme to enter the small intestine.  This action then triggers another cascade of events from the accessory organs like the gallbladder and pancreas to further digestion and allow absorption of the nutrients from the food.  

If the chyme is not acidic enough, the pyloric sphincter does not open and the partially digested food sits in the stomach, making you feel excessively full and uncomfortable.  You can also have an increased risk of causing inflammation to the stomach lining with that undigested food sitting in the stomach for too long.  If more food is consumed, the pyloric sphincter will be forced open to allow the release of that chyme that had been sitting in the stomach.  However, the critical release of bile from the gallbladder and enzymes from the pancreas could be impaired as the chyme was not acidic enough.  

Low Stomach Acid and Nutritional Deficiencies

Nutritional deficiencies are also common with insufficient hydrochloric acid levels as it aids in the liberation of nutrients that are bound to protein. Deficiencies in the micronutrients B12, folate, zinc, calcium, iron, and magnesium are common with low levels of HCl.   Zinc, in particular, has a cyclical relationship with HCl.  It is needed for the creation of HCl but if you are unable to properly liberate zinc from protein and/or absorb it, you also won’t have zinc available to create HCl.

Oh and remember when I mentioned that proper stomach acid levels trigger the release of the chyme into the small intestine which then triggers the gallbladder to release bile?  Bile emulsifies fat, making it more water-like. This process is especially important in regards to the fat-soluble vitamins - A, E, D, K.  Without appropriate bile, fat digestion is impaired and fat-soluble vitamins are not absorbed. 

The Perfect Breeding Ground For Bacterial Overgrowth

As you may be seeing so far, sufficient levels of stomach acid are imperative to not only proper digestion but also absorption of nutrients.  It also affects the bacterial balance of the microbiome.  Without proper stomach acid, there can be undigested food for bacteria to feed on.  This is where the opportunistic bacteria run wild.  They are the ones that can be creating the GI symptoms you may be experiencing like gas, bloating, constipation, diarrhea, acid reflux, skin issues, and more!  They are particularly problematic if the lining of the intestines has been compromised leading to increase intestinal permeability - AKA leaky gut. Low stomach acid can allow for other pathogenic bacteria, parasites, and fungi, like candida, to overgrow as well. 

Helicobacter pylori

There are one bacteria that I haven’t mentioned yet that can actually contribute to a deficient stomach acid environment - helicobacter pylori (H. pylori).  Helicobacter pylori (H. pylori) is a gram-negative spiral-shaped bacterium that affects up to 50% of the population worldwide, with a higher prevalence in developing countries.³  H. pylori is so common because of the source of transmission of the bacteria.  It can spread through saliva, fecal material, contaminated water, and/or poor hand washing.  

The H. pylori bacteria cannot thrive in an environment with adequate stomach acid.  It’s a rather sneak bacteria and actually secretes an enzyme that REDUCES stomach acid so that it can have a place to thrive as it burrows into the stomach lining.  

The presence of H. pylori increases the risk of having gastritis, ulcers, and even cancer.  According to cancer.gov, “Infection with H. pylori is the primary identified cause of gastric cancer.”⁴ My favorite test to determine if H. pylori is present through a comprehensive stool test called the GI MAP.  

Testing for a Microbiome Imbalance

The GI MAP is a comprehensive stool panel that analyzes the DNA of the microbes present in the stool sample.  Through this test, We are able to uncover what is disrupting the microbiome, contributing to illness, affecting digestion and absorption of nutrients of food, contributing to inflammation, and/or affecting immune function. This test evaluates the balance of bacteria, identifies pathogens or parasites, and provides info about digestive health and a marker that affects detoxification.  

The GI MAP is not only comprehensive but also extremely sensitive as it determines genotypes, provides the detection of pathogens and quantifies the microbiota detected.  The DNA technology is able to detect microbiota that previously would have been undetected in a typical culture or microscope assessment of a sample.  With all testing, one should consider clinical presentation and optimal ranges rather than standard reference ranges.

Testing for Low Stomach Acid

The Heidelberg Stomach Acid Test is the gold standard for measuring the pH of the stomach acid.  This test is done by a medical provider in which you swallow a small capsule with a radio transmitter.  The transmitter records data about the pH of your stomach after drinking a baking soda solution. The result of the test is a graph showing your pH levels at regular intervals of time. This test is often not covered by insurance.

The Betaine HCl Challenge and a simple and easy at-home test in which you take betaine HCl with meals to find your tolerance levels.  To do this, you would buy a low dose (150mg) of betaine HCl with pepsin from a natural grocery store.  With a meal containing animal protein, seafood, or poultry, take the capsule midway through the meal.  Finish your meal and observe your body for a reaction. If indigestion, warmth, burning, or heaviness in your chest/left upper quadrant of your abdomen occurs, you likely have sufficient HCl.  If no reaction occurs, you are likely low in stomach acid.  For low stomach acid, you can try increasing the number of capsules you take every 3 days.  Once you have an adverse reaction, return to the previous level that was tolerated.  Make note that some meals with lighter protein like eggs, seafood, and protein shakes may require less betaine HCl than beef, lamb, chicken, or pork.  For individuals who may already be experiencing discomfort in the stomach/esophagus or on a prescription proton pump inhibitor, upper gastric healing may need to occur first before addressing stomach acid levels.  Please consult a professional before trialing this on your own if that is the case.

The Baking Soda Test is a free, at-home option to explore as well. However, it is the least reliable.  This test should be performed first thing in the morning, prior to eating or drinking.  To perform this test, dissolve ¼ tsp of baking soda in 4-6 oz of room temperature water and drink the solution quickly.  Start timing how long it takes to burp.  If no burp has occurred after 5 minutes you can discontinue timing.  Burps that happen within 2-3 minutes can usually indicate adequate hydrochloric acid levels.  Burps that occur after 3 minutes (or not at all) can usually indicate deficient hydrochloric acid levels.  Burps that happen in less than 2 minutes can indicate excess hydrochloric acid.  Of note, a small burp should not be confused with an actual burp.  This can occur from swallowing air with the water.  I recommend doing this 2 to 3 mornings in a row.  

Stomach Acid for Digestion

In conclusion, stomach acid plays an extremely vital role in the function of digestion and absorption of nutrients.  Without adequate stomach acid, there is an increased risk for the overgrowth of pathogenic and/or opportunistic bacteria, fungi overgrowth, parasites, and nutritional deficiencies.  Dietary and lifestyle factors can negatively impact the amount of stomach acid you have present at well.  Easy at-home challenges or working with a practitioner can help determine the support you need.

The information available on this website is for general health information only and is not intended to be a substitute for professional medical advice, diagnosis or treatment. You should not rely exclusively on information provided on the Website for your health needs. You can read more about our disclaimer here.

References

1. https://www.ncbi.nlm.nih.gov/books/NBK279304/

2. https://www.ncbi.nlm.nih.gov/books/NBK537005/

3. https://www.ncbi.nlm.nih.gov/books/NBK534233/

4. https://www.cancer.gov/about-cancer/causes-prevention/risk/infectious-agents/h-pylori-fact-sheet