H-Pylori – Friend or Foe or Neither?

H-plyori or Helicobacter pylori is a bacteria found in at least 50% of all human stomachs. It is one of the top 5 most studied microbes in the world. How it lives in the stomach, why it lives in stomachs, how it gets there and why it sometimes causes disease is not understood. 


What is most hotly debated about H-pylori is whether or not the bacteria has a symbiotic  pathogenic or an opportunistic relationship with the human stomach. Scientists are not sure if it a good thing or a bad thing.

Here is what they have learned. 

It was first found living in a dog’s stomach in 1893. But then it was kind of forgotten about as it was believed bacteria could not live in the stomach’s high acid environment. It was not until the 1970s that H-pylori was rediscovered living in the mucous lining human stomachs. The mucous lining your stomach is called the mucosa. The mucosa protects the cells on the surface of your stomach from its acidic environment. It is also the place where most bacteria in your guts lives. H-pylori lives inside the mucous lining your stomach. The mucosa protects H-pylori from your stomach’s the acidic environment. 

When the mucosa is damaged, H-pylori attaches to the cells lining the stomach. H-pylori then releases toxins to create small pours in the membranes so it can spirals into the cell. Once inside the cell the bacteria wraps itself in a protective coat and begins to replicate. This is the beginning of H-pylori overgrowth and all the associated challenges it brings.

By 1983 it was decided that H-pylori is a pathogen that causes gastritis. Gastritis is inflammation of the stomach lining and causes burning pain, vomiting and loss of appetite. Long term gastritis may lead a peptic ulcer –  a hole in the stomach lining. Peptic ulcers have similar symptoms to gastritis with the addition of blood in the stools or vomit and an increase in the intensity pain. Peptic ulcers or chronic gastritis is associated with developing stomach cancer. 

Today whether H-pylori is a symbiotic, opportunistic or pathogenic bacteria living in human stomachs is hotly debated by the scientific community. Even after years of research, there is so much they do not know about this bacteria. Here is what they do know. 

H-pylori lives in at least 50% of human stomachs on this planet and it is old. At the very least this spiral shaped bacteria has been living in human guts for 3000 years. Many believe it co-evolved with humans as they transitioned from being chimpanzees to today’s Homo sapiens. 

H-pylori is transmitted in families. If your family has H-pylori, then you probably have it too. Your Mom or Dad gifted you with H-plyori when you were a kid. And it has been living there ever since. Children and most adults are not troubled by the H-pylori living in their stomachs. It not until later in life at the age of 68 that most people are diagnosed with stomach cancer with the cause being cited as H-pylori.

In a search to understand the relationship between H-pylori and stomach cancer researchers  reviewed historical medical records. They found  stomach cancer was not a big concern for most of our ancestors even though their stomaches were probably colonized by H-pylori. So what is going on here? Why are modern folks with H-plyori living in their stomaches more likely to develop stomach cancer than folks that lived 1000 years ago?

Researchers suggests that perhaps our ancestors did not live long enough for H-pylori to cause cancer. Few of our ancestors lived beyond the age of 45. 

Today the number of people with H-plyori living in their stomaches is on the decline. As is stomach cancer. In some countries, like Japan where stomach cancer was common, there has been a public policy to eradicate H-pylori. In places where there is no public policy on eradicating H-pylori, the bacteria is still on the decline. No one quite understands why this is.

The decline of H-pylori began in the 1850s coinciding with the onset on the industrial revolution in the UK and the USA. At this time there was also a rise in peptic ulcers and stomach cancer.  Some suggest that the rise in these diseases of the stomach was caused by better sanitation and cleaner water. 

The epidemic of ulcer disease in the first half of the 20th century seems likely to be an adverse effect of important public health measures undertaken in the latter half of the 19th century.1

It is also suggested that H-pylori began its decline because of these measures. Yet, its decline during a period when stomach cancer and peptic ulcers were on the rise is confusing. Perhaps there is more to these diseases than H-pylori.

Today, the decline of H-pylori has participated in an increase of people suffering asthma, gastric reflux (also called GERD), Barrett’s syndrome (damage to the esophagus due to chronic acid reflux) and cancer involving the esophagus. Researchers have also linked the decrease of H-pylori in stomachs with the increase in obesity in society. 

H-pylori plays a role in stimulating and curbing our appetites. H-pylori aids in regulating our appetites by stimulating the hormones: lepton and ghrelin. While the obesity crisis is complex, scientists can not help but wonder if the decline in H-pylori plays a role in this significant public health challenge. 

H-pylori also helps in reducing stomach acids. Stomach acids are necessary to break down proteins and minerals so they can be absorbed further down your digestive tract. But ask anyone who suffers with acid reflux and they will tell you too much acid in your stomach is painful. 

Let’s explore how H-pylori helps balance your stomach acids. H-pylori excretes urea as a waste product of protein metabolism. You also release urea a waste product when you pee. In your stomach, when H-pylori releases urea it also releases an enzymes that changes the urea to ammonia and bi-carbonate. Ammonia and bi-carbonate are alkaline substances. When an alkaline substance meets an acid, the acid is neutralized and loses its burn. 

Converting urea to alkaline substances is one of the ways H-pylori manages to survive in your stomach’s high acid environment. 

Many of the conditions that are on the rise as H-pylori declines are associated with an overly acidic environment in the stomach. Esophageal reflux, Barrett’s syndrome and cancer of the esophagus are all caused by acid moving from stomach into the esophagus. When H-pylori lives in the upper area of the stomach where it joins the esophagus, this part of the stomach is less acidic. Perhaps this why with the decline of H-pylori, there is a rise in diseases of the lower esophagus. 

It is interesting to note that most stomach cancers associated with an overgrowth of H-pylori occur in the lower part of the stomach. This is the most acidic area of a healthy stomach. Does H-pylori’s ability to create an alkaline environment somehow trigger the growth of cancerous cells in this part of the stomach? One needs to wonder?

What we do know is the sale of ante acids in North America earned pharmaceutical companies 5.15 billion dollars in 2022. It is estimated that by 2027 the sale of ante acids will be worth 6.44 billion. Again we need to wonder if the decline H-pylori with its ability to neutralize stomach acids is contributing to the rise of ante acid use to relieve the symptoms of acid reflux or as it is commonly called GERD. 

No one is sure why the decline of H-pylori in the broader population has lead an increase in asthma. 

One other important piece of research needs to be consider in trying to understand the relationship between our stomachs and H-pylori. Other bacteria have been discovered to be living in human stomaches including: Prevotella, Streptococcus, Veillonella, Rothia and Haemophilus. Some studies suggest that a decline in the Streptococcus and Prevotella bacteria in your stomach causes an imbalance in H-pylori. 

To sum up, scientists cannot agree if we have a symbiotic or pathogenic relationship with H-pylori. One thing they do know is H-pylori survives in your stomach, moves about and replicates. We also know that H-pylori has different responses to the different environments within your stomach. 

  1. DOI: 10.1111/jgh.14090