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Heartburn and Reflux – the Role of Stomach Acid

Do any of these sound familiar? A sensation that foods, especially meat, just “sit in your stomach” for hours; acid reflux and heartburn; belching, bloating, and gas; bad breath; constipation or diarrhea; nausea after taking supplements; undigested food in stools. If so, you may have an issue with stomach acid.

While in some cases acid reflux and heartburn are caused by an overproduction of hydrochloric acid (HCl), there is a theory that low stomach acid plays a role. Most people actually don’t produce enough, especially as we age. About seventy-five percent of adults over age 60 have low stomach acid. Heartburn may be a sign of acid in the wrong place, as opposed to too much acid. There is a muscle connecting the esophagus to the stomach that usually only opens to let food into the stomach. Sometimes, however, it opens inappropriately, allowing the acidic stomach contents to come in contact with the esophagus, which does not have a protective lining like the stomach has. This can account for that burning sensation we feel, even with low amounts of acid.

Perils of low stomach acid

Chronic low stomach acid, or hypochlorhydria, should be taken seriously. It can lead to nutrient deficiencies, GI infections, and increase your risk of food sensitivities.

Stomach acid is necessary for proper protein digestion in the stomach. Low stomach acid can lead to less protein digestion, potentially resulting in protein deficiency. Stomach acid is also necessary for proper absorption of certain minerals – calcium, iron, and zinc - and vitamins, especially the B vitamins including B12, B6, and folate.

Adequate stomach acid is also needed for fat digestion. When acidic stomach contents enter the small intestine, the gallbladder is triggered to release bile, which is crucial for emulsifying fats. Bile is also important for the proper digestion and absorption of fat-soluble vitamins like A, D, K, and E. Likewise, acid triggers the pancreas to release its own digestive enzymes. Having low stomach acid reduces all of these processes, leading to inadequate digestion and absorption of vital nutrients.

As if this weren’t bad enough, undigested food can become a source of fuel for bacteria and yeast in your small and large intestine, potentially leading to increased gas, gut dysbiosis and small intestinal bacterial overgrowth. This gas can also lead to increased pressure on the stomach and the sphincter connecting it to the esophagus, leading to reflux.

Lastly, stomach acid is our first line of defense against pathogenic (harmful) invaders such as bacteria, viruses, and parasites, and can help prevent small intestinal bacterial overgrowth. Food poisoning, for example, is much less likely if your stomach acid is at a healthy level.


There are several potential causes of low stomach acid. One of the primary causes is aging, as mentioned above. Antacids, proton pump inhibitors, and H2 blockers are another major contributor. (These medications are clearly indicated in some situations, however.) Certain gastrointestinal conditions like H. Pylori infection, small intestinal bacterial overgrowth, and food sensitivities can be culprits. Being on a vegetarian or vegan diet for a long time and chronic stress can also reduce the normal acid production in your stomach. Autoimmune disease, including autoimmune gastritis, is another potential cause.


There are a few ways to test for low stomach acid. Ask your healthcare provider about the Heidelberg capsule test, which measures the hydrochloric acid (HCl) levels in your stomach. There is a self-test as well using HCl supplements. However, there are contraindications, so speak with your provider first to find out if it is right for you.

What you can do now

If you have determined that your HCl levels are low, there are many avenues to explore. Start with sitting at a table to eat in a calm and peaceful atmosphere; stress negatively affects digestion. Chew your food thoroughly. Pay attention to your food and the people you may be eating with. You may want to try eating smaller, more frequent meals. Try to avoid drinking large quantities of water during a meal. Rather, spread out your beverages throughout the day. Adding lemon or lime juice, or some apple cider vinegar, to regular or carbonated water can help with digestion at mealtimes. Eating some acidic foods with meals can also help, including fermented foods, citrus fruits, and pineapple, for example. Acidic foods are not for everyone, however. If you suffer from reflux, limiting certain foods can be helpful, such as orange juice, caffeine, high-fat meals, alcohol, tomato products, spicy foods, mint, and alcohol.

Supplementation, either food-based or in pill form, is also an option. HCl is available in supplement form, but the contraindications are many. Ox bile and bile salts supplements can help with fat digestion. Digestive enzymes are the least potentially irritating. They help in the digestion of protein, fat, and carbohydrates. Digestive bitters are another option to stimulate acid secretion. Diluted apple cider vinegar or lemon in water is another option. Speak with a knowledgeable practitioner to find out if any of these supplements are right for you.

Lastly, do not underestimate the power of stress; chronic stress can suppress stomach acid, so make sure to address this aspect of your life as well.

The information provided in this article is intended for general use only and is not to be used in place of medical advice from a licensed health professional.

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