What is Stomach Gas?
The term stomach gas is often used to describe the presence of gas in the upper gastrointestinal tract. This includes the esophagus (gullet) and first portion of the small intestine (duodenum). Stomach gas differs from gas in the lower bowel and colon in that it has a higher quantity of air swallowed during eating and by mouth breathing.
A host of signs and symptoms are attributed to excess gas in the stomach and upper gut. However, the volume of gas associated with excess belching, bloating and flatulence is rarely more than normal. These symptoms may often be associated to underlying gastrointestinal disorders, of which stomach gas is one of the many symptoms.
Causes of Stomach Gas
Gas within the upper gastrointestinal tract is a result of many factors including gas produced by :
- Bacteria in the gut (normal and pathogenic bacteria).
- Digestion and decomposition of food.
- Air swallowing (aerophagia).
- Carbonated drinks and effervescent solutions.
These causes may be a result of normal activity within the upper gastrointestinal tract (esophagus, stomach, duodenum), voluntarily induced or it may be due to a number of conditions and diseases. The most common symptom of increased gas in the upper gastrointestinal tract is excessive belching (burping) and bloating. Other symptoms referred to as indigestion may also be present. Refer to Severe Indigestion Causes and Symptoms for more information.
How Does Gas Get Trapped/Produced in the Stomach?
It is difficult to isolate whether the gas is trapped or produced only in the stomach. Usually any cause of gas within the upper gastrointestinal tract is referred to as a ‘gassy stomach’. At times, gas may be produced lower down the gastrointestinal tract and travels back into the upper gastrointestinal tract.
The most common, innocuous cause of excessive gas in the upper gastrointestinal is air swallowing (aerophagia).
- The air travels down the esophagus and may enter the stomach or continue through to the duodenum. It usually stays in the esophagus and is passed out as a burp.
- If it continues through to the stomach or intestine, it may build up for a while where it causes other symptoms like stomach or intestinal cramps and abdominal bloating.
- Once the pressure builds up in the stomach or duodenum, the air can then force its way up the gut and passes out as a burp.
- Less frequently the air may travel further down the gastrointestinal tract, into the latter parts of the small intestine, through to the colon and is passed out as flatulence.
Carbonated and fermented drinks are another common cause and in this case the gas quickly passes into the stomach from where it then travels up the esophagus and is passed out as a burp.
The most common pathogenic cause of a gassy stomach is due to H.pylori infection of the stomach and first part of the intestine. This bacteria, Helicobacter pylori, has an affinity for the stomach lining. It produces a number of substances that neutralize the protective mucus lining of the stomach. This allows stomach acid to cause irritation of the stomach lining (gastritis) or the development of stomach ulcers. As part of its mechanism of action to shield itself from the gastric acid, H.pylori is able to neutralize the acid around it and in the process of doing so, it produces gases like hydrogen and carbon dioxide.
Certain foods are more ‘gassy’ than others. These foods usually have a high carbohydrate (starch, raffinose, lactose, fructose, sorbitol), sulphur (sulfur) and/or fiber content. While gassy foods are more responsible for gas build up in the lower gastrointestinal tract (large intestine) where the gas is passed out as flatulence, it may also contribute to gas production in the upper gastrointestinal tract.
Gassy foods do not affect every person by causing gas buildup, excessive belching, bloating and flatulence. Some people are more prone to gas production due to the presence of large populations of certain bacteria in the gut, intolerances or impaired digestive processes.
Some of these gassy foods include :
- Artificially sweetened foods
- Brussel sprouts
- Wheat bran
- Other whole grains
Food Intolerance and Malabsorption
Intolerances and malabsorption may be linked to the ‘gassy’ foods mentioned above. The more common of these are due to :
- Fizzy drinks or sodas have carbon dioxide bubbles to improve the flavor of the drink. Carbon dioxide is dissolved in the solution and slowly releases over a period of time.
- Fermented beverages like beer have a high gas content due to the fermentation process.
- Certain effervescent drinks for indigestion may increase gas production.
- Alkalizing agents for kidney stones and UTI’s may also be responsible for gas production in the stomach.
Air Swallowing (Aerophagia)
Air swallowing is usually due to mouth breathing and may occur for the following reasons :
- Nasal congestion
- Eating or drinking too quickly
- Cigarette smoking
- Poorly fitted dentures
- Hyperventilation (anxiety)
- Chewing gum
- Snoring and possibly the use of CPAP machines for sleep apnea
Gassy Stomach Diseases
Certain diseases may cause increased upper gastrointestinal gas or the excess gas may be a symptom of the disease.
- Bile reflux
- Eating disorders
- Food poisoning
- Gastric dumping
- Gastrointestinal obstruction
- Hiatal hernia
- H.pylori infection
- Irritable bowel sydrome (IBS)
- Pancreatic insufficiency
- Peptic ulcers
- Small intestinal bacterial overgrowth (SIBO)
Signs and Symptoms
The most prominent symptoms of excessive stomach gas include :
- Excessive belching
- Bloating – sensation of feeling full
- Upper abdominal distension
- Gastric pain or stomach ache
- Stomach cramps
However, many of these signs and symptoms may not be directly related to the presence of excess stomach gas but rather as a result of the causative condition as mentioned above. Flatulence, generalized abdominal bloating and intestinal cramps may be experienced with gas in the lower gastrointestinal tract (jejunum and ileum of the small intestine and the large intestine).
Prevention of Stomach Gas
Preventing a buildup of gas in the stomach depends on the cause. With pathological causes like infectious gastritis, medical treatment is necessary. With other more common causes of stomach gas related to air swallowing and carbonated beverages, avoiding the causative factors will prevent or at least significantly reduce stomach gas.
Tips to Avoid Stomach Gas
- Eat slowly, chew carefully and swallow food that is throughly chewed.
- Avoid carbonated beverages like fizzy sodas, sparkling bottled water, beer and sparkling wine.
- Do not chew gum repeatedly throughout the day.
- Do not use high doses of antacids, especially over a prolonged period. Always see a doctor about any stomach condition that is persisting rather than self-medicating.
- Consult with an otolaryngologist (ENT specialist) with regards to any persistent nasal congestion.
Persistent stomach gas should be investigated by a medical doctor, especially if it is associated with stomach pain, abdominal swelling, loss of appetite and unintentional weight loss.