Research & Education

Is There a Link between Low Stomach Acid and Heartburn?

Stomach acid is produced by the parietal cells, consisting primarily of hydrochloric acid (HCl). Stomach acid has two vital roles in human health. The first vital role of stomach acid is required to properly digest food. The second vital role is to protect the body from potential pathogens through food or water. Generally, a normal fasting gastric pH is less than 3.0 due to its acidic nature. When values are above 3.0, the individual is considered to have hypochlorhydria or low HCl. When values are above 7, the individual is deemed to have achlorhydria or absent HCl. 

There is a large variance in the reported prevalence of low stomach acid in the general population. It is believed that stomach acid secretion may gradually decline with natural aging. Low stomach acid may be secondary to an underlying medical condition, such as pernicious anemia, gastric bypass, hypothyroidism, and Helicobacter pylori (H. pylori) infection. H. pylori is estimated to occur in approximately half of the world’s population. It is well understood that long-term use of protein-pump inhibitors is associated with low stomach acid. 

Having low stomach acid is problematic for overall health. Stomach acid is required for proper protein digestion, as gastric protein-digesting enzymes function optimally at a low pH. When protein is poorly digested, it may result in inadequate mineral absorption and is potentially associated with food allergenicity. Too little stomach acid may be linked to reduced absorption of key micronutrients, such as calcium, iron, folate, vitamin B6, and vitamin B12. Moreover, having low stomach acid is associated with potentially harmful microbial environments that may be seen in individuals with dysbiosis, small-intestinal bacterial overgrowth, or organisms such as Clostridium difficile, Campylobacter, or Salmonella

The adverse consequences of low stomach acid may amount to various undesirable gastrointestinal complaints. For instance, this may be associated with occasional nausea, bloating, diarrhea, abdominal pain, postprandial fullness, vomiting, or constipation. Symptoms such as occasional heartburn or acid regurgitation may also be associated with low stomach acid, even though these symptoms may be mistakenly assumed to result from excess stomach acid.

Approximately 10% to 15% of the general population have dyspeptic symptoms that often overlap with gastroesophageal reflux disease (GERD), consisting of heartburn or regurgitation. One clinical study analyzed 89 outpatients with dyspeptic symptoms who had a mean age of 55.6 years. They observed that gastric hypochlorhydria was only seen in female dyspeptic patients. Furthermore, the total symptom scores and related dysmotility scores in the female dyspeptic patients were significantly higher in those with gastric hypochlorhydria than in those with gastric non-hypochlorhydria. The researchers suggest that low stomach acid was involved in exacerbating dyspeptic symptoms. 

Betaine HCl supplementation may promote healthy gastric pH levels. Having inadequate stomach acid may be associated with a risk for maldigestion, malabsorption, and potential gastrointestinal side effects including heartburn.

By Danielle Moyer, MS, CNS, LDN