The Stomach, Stomach Ulcers and Helicobacter pylori

The stomach is a hollow, muscular organ that receives and digests food. The lining of the stomach produces hydrochloric acid and digestive enzymes. After a meal, the stomach contains an acidic, churning mass of food and enzymes. We would expect this mixture to be an inhospitable environment for bacteria, but there are some that can survive or even thrive inside the stomach. The presence of a bacterium named Helicobacter pylori, which lives in many people’s stomachs, can sometimes cause inflammation of the stomach lining and stomach ulcers.

Stomach ulcers are also known as gastric or peptic ulcers. The term “peptic ulcer” is the general name for an ulcer that occurs in the stomach or in the duodenum, which is the first part of the small intestine.

When food is swallowed, it passes down a tube called the esophagus and enters the stomach. The stomach is a J-shaped organ which is located on the left side of the upper abdomen. It’s covered by the liver and has a volume of about one liter, but after a meal can expand to around four liters. When we eat, glands in the lining of the stomach make hydrochloric acid, which makes the fluid inside the stomach acidic. The pH of this fluid, which is known as gastric juice, is about 2. The pH scale runs from 0 to 14, with the lower numbers indicating more acidic conditions. Stomach glands also produce a chemical called pepsinogen. When pepsinogen enters the gastric juice it’s converted into an enzyme called pepsin by the hydrochloric acid. The pepsin then begins the digestion of the proteins that have entered the stomach cavity after a meal.

Food generally stays in the stomach for about two to four hours. When the stomach has finish its digestion, the mixture containing the partly digested food, which is known as chyme, is gradually sent into the small intestine to complete its digestion. A muscle called the pyloric sphincter controls the passage of the chyme into the small intestine.

Food is moved through the esophagus into the stomach, then into the small intestine and finally into the large intestine, by a process called peristalsis. Peristalsis is a series of muscular contractions that travel in waves along the walls of the digestive tract. Sometimes the stomach or small intestine will produced growling sounds. These sounds are called borborygmi, and are created when peristalsis squeezes gas and liquid in the stomach and intestine. The gas is swallowed air or is produced by bacteria in the digestive tract.

A mucus layer covers the stomach lining to protect it from an acid attack or from an attack by pepsin. The hydrochloric acid kills most bacteria that enter the stomach, but not all of them. Stomach ulcer bacteria, for example, burrow deep into the mucus layer and move towards the stomach lining, where they are protected from the acid. These bacteria (whose scientific name is Helicobacter pylori, or H. pylori) also make an enzyme called urease, which converts the urea secreted by the stomach lining into ammonia. Ammonia is a base, and helps to neutralize any acid which approaches the bacteria. Some other bacteria may be able to survive the journey through the stomach if they enter the stomach in large numbers, or if they are surrounded by food that temporarily increases the pH.

The body of H. pylori consists of just one cell. This cell often has a spiral shape and has tail-like extensions attached at one end, which are called flagella. The flagella can rotate like a propeller, driving the bacterium into the mucus layer that covers the stomach lining. The presence of H. pylori causes the stomach lining to become inflamed and the mucus layer to be damaged. Inflammation of the stomach lining is known as gastritis. Substances made by the bacteria may contribute to the gastritis and mucus damage, but scientists think that the major cause of the stomach inflammation is the production of inflammatory chemicals by the body’s white blood cells as they attempt to destroy H. pylori. Gastritis usually results from a Helicobacter infection, but there are other possible causes, such as the ingestion of aspirin and ibuprofen.

Gastritis can eventually lead to a sore in the stomach lining known as an ulcer. An ulcer may also be created in the first part of the small intestine, which is known as the duodenum. These ulcers are called peptic ulcers. A peptic ulcer in the stomach may also be referred to as a gastric ulcer or a stomach ulcer, while a peptic ulcer in the duodenum may be called a duodenal ulcer.

Scientists have discovered that 80% of stomach ulcers and 90% of duodenal ulcers are caused by Helicobacter pylori. It wasn’t until 1982 that the bacterial cause of stomach ulcers was discovered. Before this time, ulcers were thought to be caused by stress and too much stomach acid. Barry Marshall and Robin Warren, two Australian doctors, discovered that H. pylori could cause ulcers. This idea was greeted by skepticism and even derision by other scientists. Barry Marshall drank an H. pylori culture to prove his theory and developed gastritis as a result. Both doctors won a Nobel Prize for Medicine in 2005 for their discovery.

The main symptom of a stomach ulcer is pain, but there may also be loss of appetite and nausea. Untreated ulcers can lead to serious complications. The ulcers may bleed, which can cause anemia and fatigue. They may even become big enough to produce a hole in the stomach wall, allowing stomach contents to enter the abdominal cavity. This results in a dangerous inflammation called peritonitis. Ulcers may partially or completely block the duodenal opening.

Many people have been found to have Helicobacter pylori infections without experiencing any discomfort, though they may still have low-grade gastritis. In fact, it’s estimated that at least 50% of the world’s population carries H. pylori within their bodies, with more people infected in certain countries than in others. Scientists don’t know why some people develop symptoms of the infection and others don’t. They also don’t know how people become infected with H. pylori, although they suspect the bacteria may be obtained by eating and drinking materials contaminated by infected saliva or feces. Scientists recommend normal sanitary procedures to reduce the chance of an H. pylori infection.

It’s important to treat stomach ulcers and gastritis caused by H. pylori, because a long-term infection increases the risk of stomach cancer. Antibiotics prescribed by a doctor are the first line of attack. They take two to three weeks to kill the bacteria. The doctor may also prescribe drugs to reduce the amount of acid that the stomach makes, since the acid irritates ulcers. The acid-reducing medicine will need to be taken for a longer period of time than the antibiotic.

Patients can also help themselves by eating frequent smaller meals rather than less frequent, larger meals. Small meals reduce the amount of acid that the stomach makes. People with ulcers should avoid eating close to bedtime, since this will stimulate acid production during the night. Caffeine increases the production of stomach acid, so caffeinated drinks should be reduced or avoided. Smoking has been shown to contribute to ulcer formation and to slow healing of an ulcer. Emotional stress doesn’t cause ulcers but can increase the pain of an existing ulcer.

A bland diet used to be recommended for relieving ulcers. This diet contained soft foods like mashed potatoes and cream of wheat, and was low in fat, non-acidic and contained no spices or alcohol. Today most doctors say that a bland diet is unnecessary and that a person suffering from an ulcer should instead eat healthy and nutritious food. However, in some people certain spices or other foods increase ulcer pain and should be avoided. Research suggests that lactic acid bacteria or fermented foods can reduce the level of H. pylori in the body.

Bismuth subsalicylate (such as Pepto-Bismol and other brands) can be bought in drug stores. Bismuth subsalicylate coats ulcers and helps block them from stomach acid. It also seems to help kill H. pylori, but it can’t replace antibiotics. If your doctor is giving you medication for stomach ulcers and you want to add bismuth subsalicylate to the treatment you should let your doctor know.

There is plenty of research being conducted to learn more about how Helicobacter pylori affects the body, how it is transmitted and how it can be eradicated. As we learn more about the bacterium, its behavior and the body’s reaction to it, we will almost certainly develop better ways to deal with H. pylori infections.