Low Stomach Acid: Interventions for Optimal Digestion

Here’s the lowdown on low stomach acid and some lifestyle strategies to handle it.

If you have reflux or GERD, you may be used to thinking of your digestive issue as resulting from too much stomach acid, but too little stomach acid can also be the culprit. 

Understanding the role of stomach acid in digestion

When the food you eat arrives at the stomach, gastric or digestive “ juice” is released in order to help break down the food for better digestion and absorption. Hydrochloric acid (HCl) is a strong acid and a main component of gastric juice. The HCl has two main jobs: 1) help break down food (especially proteins) so its nutrients can be easily absorbed in the gastrointestinal tract, and 2) help the immune system by killing invading bacteria and other microbes that could be dangerous. 

Having an appropriate amount of HCl is important. Too much acid can irritate the stomach lining and contribute to reflux, GERD, and ulcers, among other things. Too little acid can also cause acid reflux, among other issues. This is an unfortunate (and sometimes confusing) duality for those who have GERD or experience reflux, and one that bears investigation if typical GERD management isn’t working.

What is hypochlorhydria?

Hypochlorhydria is when the stomach doesn’t produce enough hydrochloric acid; therefore, the gastric juice is not acidic enough. A more severe condition called achlorhydria occurs when virtually no hydrochloric acid is produced. Low stomach acid can lead to malnutrition, a variety of digestive issues, small intestine bacterial overgrowth (SIBO), and even gastric cancer. Some studies estimate that 2% of the population under age 60 suffers from hypochlorhydria; that jumps to 5% in people aged 65 and older.

A diagnosis of hypochlorhydria is made by testing the acidity of the stomach fluid (generally, a gastric fasting pH above 3 is considered hypochlorhydric) and perhaps additional blood tests for specific nutrient levels since a lack of stomach acid hinders the absorption of specific vitamins and minerals, such as vitamin B12, iron, and calcium. 

Signs and symptoms of hypochlorhydria

While symptoms of low hypochlorhydria tend to show up a few hours after meals, they often seem like general digestive upset, like you might get from overeating. And some of the symptoms of low stomach acid are the same as those for GERD, such as heartburn, nausea, indigestion, bad breath, and frequent belching. This makes it tricky to determine if you actually have low stomach acid or some other issue. However, there are other indicators that you might be dealing with hypochlorhydria and not just a random case of heartburn; these are:

• feeling overly full after a regular-sized meal (sometimes called “early satiety”)
• the presence of undigested food in bowel movements

What causes hypochlorhydria?

There are a variety of factors and circumstances that may lead to low stomach acid. Some of these include:

• being over age 65 (HCl production naturally decreases with age)
• stomach surgery, such as gastric bypass
• untreated bacterial infection caused by H. pylori
• zinc deficiency, since the mineral is needed to make stomach acid
• long-term use of proton pump inhibitors (PPIs), typically used to treat GERD
• smoking and/or drinking alcohol
• chronic stress
• eating a nutrient-poor diet 

How do PPIs cause hypochlorhydria?

Proton pump inhibitor medications (PPIs) chronically reduce gastric acid production, but taking them long-term can come with a price. Studies have shown that, compared to other acid-suppressing medications (including antacids), the long-term use of PPIs can lead to hypochlorhydria, which can then lead to nutrient deficiencies and their consequences. Taking PPIs longer than prescribed or necessary (or for off-label reasons) can also cause imbalances in the gut microbiota. PPIs were designed to be temporary medications, so consult with your doctor about the usage length most appropriate for you. 

Lifestyle strategies for stimulating stomach acid production

Because there are so many potential causes of low stomach acid, treating it requires getting to the root issue. Sometimes, as with an H. pylori infection, the answer can be as simple as taking an antibiotic. Or, your doctor may switch your reflux medication or prescribe an HCl supplement like Betaine HCl.  

But there are some ways you can support your body’s natural stomach acid production and gut health, such as:

• Consume adequate zinc — the body uses zinc to make HCl. Food sources of zinc are your best bet (yogurt, beans, fortified cereal, nuts and seeds, and beef are good sources). Talk to your doctor before considering a zinc supplement.
• Start your meal with a salad incorporating some bitter greens — lab test-tube studies have shown that digestive bitters stimulate gastric acid production, but human evidence is lacking. Still, if you tolerate them, having a healthy salad with bitter greens like arugula, endive, or mustard greens may help get that HCl flowing. Top it with an apple cider vinegar-based dressing for an extra edge, but don’t expect it to work miracles because the science isn’t there yet. 
• Decrease your stress level — a body that is in “fight or flight” mode is one that has its digestive system on low power—that includes slowed stomach acid production.
• Chew your food thoroughly and don’t eat in a rush — the digestive system responds better overall to slower eating, and chewing thoroughly may help food break down better in the gastrointestinal tract. 

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5. _{Guilliams, T. G., & Drake, L. E. (2020). Meal-Time Supplementation with Betaine HCl for Functional Hypochlorhydria: What is the Evidence?. Integrative medicine (Encinitas, Calif.), 19(1), 32–36.}
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