Is Low Stomach Acid the Cause of H Pylori?

Helicobacter pylori (H. pylori), previously known as Campylobacter pyloridis, is a bacteria that lives in the stomach. Two Australian scientists, Barry Marshall and Robin Warren, won a Nobel Prize for discovering that the bacteria plays a role in the formation of gastric ulcers (peptic ulcers) and chronic gastritis. It’s since been established that H. pylori is associated with not only ulcers but also with stomach cancer and gastric lymphoma.

What’s alarming and surprising is that it’s estimated that around 50% of humans have the bacteria in their upper gastrointestinal tract. Most won’t be aware of it though. Although the bacteria results in inflammation of the stomach, it doesn’t produce any symptoms in around 80% of cases. So, what’s the cause of H pylori?

H. Pylori Causes

H. pylori infection is most prevalent in developing countries. Typically, it’s contracted in early childhood, through transmission from mother to child. It then remains in the stomach and progresses to a chronic infection later in life. In contrast, in developed countries, the prevalence of H. pylori increases with age.

Numerous scientific studies have examined how the bacteria can be transmitted. Unfortunately, the routes remain a matter of circumstantial evidence and speculation rather than fact.

According to this review, for the general population, the most likely route of transmission is from person to person, either through oral contact or fecal-oral contact. In support of this, H. pylori has been detected to vomit, saliva, dental plaque, gastric juice, and feces. H. pylori infection has also been experienced clustered within families.

Waterborne transmission, probably due to fecal contamination, is another important likely source of infection. This is particularly so in parts of the world in which untreated water is common. Recent investigations, such as this study, have linked H. pylori infection with consumption of well water that’s contaminated with the bacteria.

The most recent thought is that H. pylori may be transmitted by the housefly. Although there’s not a lot of evidence to support this, scientists find the hypothesis appealing as flies are known to carry many other infectious diseases.

Some strains of H. pylori are capable of triggering a greater inflammatory response in the stomach than others, as they carry a cag pathogenicity island (cag PAI) encoded protein. Research as found that over half of the H. pylori strains in Western countries may have this protein.

The Relationship Between Stomach Acid and H. Pylori Infection

What’s particularly interesting to note about H. pylori, and it’s something that you might not be aware of, is how it establishes itself in the stomach. Gaining an understanding of this is important in successfully eliminating the bacteria.

Scientists have discovered a relationship between the amount of stomach acid secreted and the colonization patterns of H. pylori (both density and distribution), and the severity of the body’s inflammatory response to the infection. The acidity of the stomach lumen (cavity) determines whether an ulcer will be duodenal (in the first part of the small intestine) or gastric (in the stomach).

Why is this?

When H. pylori makes its way into the stomach to begin colonization, it has to survive the acidic pH of the stomach lumen, or cavity. It moves through it, and inserts itself into the mucus lining near the stomach’s epithelial cell layer which lines the stomach. In contrast to the stomach lumen, the epithelial cell surface has a more neutral pH environment, where the bacteria can happily live.

In people that produce large amounts of acid, the H. pylori bacteria will colonize the pyloric antrum of the stomach (the last major compartment of the stomach) to avoid the parietal cells in the stomach corpus (the main part of the stomach) that secrete the acid.

H. Pylori Thrives in Low Stomach Acid

While H. pylori can avoid being wiped out by gastric acid, low levels of gastric acid make it quite easy for the bacteria to enter and infect the stomach. Even if your levels of stomach acid are only temporarily low, the bacteria can enter and establish itself, then migrate below the mucus layer of the stomach to protect itself from rising stomach acid.

What’s more, once colonized, H. pylori create ammonia as a waste product. Since ammonia is alkaline, it can reduce the acidity of the stomach and make it a more hospitable home for the bacteria.

Even worse, studies have shown that chronic H. pylori infection can inhibit acid production in the stomach by greatly consuming hydrogen, which is needed by the stomach to produce acid.

According to some studies, even if a person gets rid of all the H. pylori bacteria, it can take up to a year for the production of stomach acid to recover properly and return to normal.

How Acid-Lowering Medication Increases the Risk of Contracting H. Pylori

The chance of getting infected with H. pylori goes up substantially if you’ve used any type of acid reflux or heartburn medicine that blocks the production of stomach acid.

Most acid reflux and heartburn medications are what are known as proton pump inhibitors (PPIs), which work by turning off the body’s proton pump that makes hydrogen. Without hydrogen, the body can no longer produce stomach acid, and the reflux symptoms disappear.

Yet, the reality is that these drugs were actually developed to kill H. pylori bacteria. The bacteria needs to consume hydrogen to survive. By turning off its production, the bacteria starves and dies. What happened was that scientists realized that turning off gastric acid production could also cure the symptoms of reflux and heartburn. So, they began marketing PPI products for that purpose.

The PPI drugs can starve H. pylori. However, your odds of having a H. pylori infection increase if you’ve ever used one of these drugs.

The reason why is that most people won’t start making hydrogen again for up to 3 weeks after ceasing to take proton pump inhibitor medication. This creates a window of opportunity where stomach acid is low, and it sets up an opportunity for H. pylori to re-infect the body.

Although absence of hydrogen may have starved the H. pylori out of existence, two or three weeks exist where new bacteria can come in and establish themselves. During this time, individuals may begin making enough hydrogen to feed bacteria but not enough to create an acid barrier to keep them out.

It’s not just H. pylori that may infect the body. There are other types of bacteria that live on sugar instead of hydrogen. If these bacteria can flourish in the three week acid-free window in the stomach, they can create an alkaline environment that could stay more alkaline after the body begins making stomach acid again. This is because the waste product from most bacteria is alkaline.

Suspect You Might Have H. Pylori?

Common symptoms of H. pylori include heartburn, acid reflux, stomach pain, bloating, constipation, and sometimes diarrhea. It can also cause seemingly unrelated symptoms such as fatigue, depression, headaches, and skin conditions.

Testing for H. pylori infection may be performed on blood, stool, or breath samples. Also, biopsies of tissue from the lining of the gastrointestinal tract, obtained during endoscopy, can be tested for the presence of H. pylori.