Flatulence

What is flatulence?

Flatulence is the presence of excess wind or gas in the digestive tract. This gas consisting primarily of carbon dioxide, oxygen, hydrogen and methane gas is formed in the large intestines as a result of action of bacteria on undigested food. It is natural to pass gas 12-14 times in a day, both as burping (or belching) and as flatus.

Flatulence results from fermentation or the chemical breakdown of food by bacteria that live normally in intestine or colon. There are different types of these bacteria, and the amount and type of gas produced depends on the mix of bacteria present in the intestine.

What are the causes?

Gas in the digestive tract comes from two sources:

• Normal breakdown of certain undigested foods by harmless bacteria naturally present in the large intestines.
  
• Air swallowing (aerophagia): Everyone swallows small amounts of air when eating and drinking. Eating or drinking rapidly, chewing gum, smoking or wearing loose dentures can also cause some people to take in more air.

• Eating large amounts of non-digestible foods such as fibre.
  
• Eating foods that are not tolerated, as in lactose intolerance.
  
• Acute pancreatitis
  
• Irritable bowel syndrome
  
• Malabsorption or inadequate absorption of nutrients from the intestinal tract, often accompanied by diarrhoea.
  
• Use of oral antibiotics
  
• Gastrointestinal cancer and its treatment

Which foods cause gas?

Most foods that contain carbohydrates may cause gas. These include sugars, starches and dietary fibre.

Sugars: The sugars that cause gas are raffinose, lactose, fructose and sorbitol. Raffinose is present in large amounts in beans and small amounts are present in cabbage, broccoli, other leafy vegetables and whole grains.

Lactose is the natural sugar in milk. It is also present in milk products, such as cheese and ice cream, and processed foods such as milk breads and salad dressings. Lactase is an enzyme present in the body that helps in breakdown of lactose. However, it may be absent or present in inadequate amounts in certain people, resulting in a condition known as lactose intolerance. Also, as people age, their enzyme levels decrease. As a result, they may experience increased amounts of gas after eating foods containing lactose.
Fructose is naturally present in fruits, onions, and wheat. It is also used as a sweetener in some soft drinks and fruit drinks.

Sorbitol is a sugar found naturally in fruits, including apples, pears, peaches and prunes. It is also used as an artificial sweetener in many diabetic foods and sugar-free candies and gums.

Starches: Most starches including potatoes, corn, noodles and wheat produce gas. Rice is the only starch that does not cause gas.

Fibre: Many foods contain soluble and insoluble fibre. Soluble fibre dissolves easily in water and makes a soft, gel-like texture in the intestines. Soluble fibre present in certain foods like beans, peas and most fruits, is not broken down until it reaches the large intestines where its digestion causes gas. Insoluble fibre always passes unchanged through the intestines and produces little gas. Wheat bran and some vegetables contain this kind of fibre.

Food products that contribute to gas production

What are the symptoms?

The most common symptoms of gas are belching, flatulence, abdominal bloating and abdominal pain.

Belching is emitting wind noisily from the stomach through the mouth. An occasional belch during or after meals is normal and releases gas when the stomach is full of food. However, in people who belch frequently, the problem may be because of swallowing too much air and releasing it before it enters the stomach. Sometimes a person with chronic belching may have a digestive tract disorder, such as peptic ulcer, gastro-oesophageal reflux disease (GERD) or gastritis.

Flatulence is passage of gas through the anus. Passing gas this way 10-20 times a day is normal, but more often may be embarrassing.

Abdominal bloating is usually the result of an intestinal motility disorder, such as irritable bowel syndrome (IBS). This condition is characterised by abnormal movements and contractions of intestinal muscles and may give a feeling of bloating because of increased sensitivity to gas. Other diseases such as Crohn’s disease and colon cancer may also cause abdominal bloating.

Abdominal pain and discomfort may be present when there is excess gas in the intestines.

How is it treated?

The most common treatments to reduce the discomfort of gas are changing dietary habits, taking medication and reducing the amount of air swallowed. Medicines such as antacids with simethicone and activated charcoal and reduce the symptoms. Simethicone which is a foaming agent that joins gas bubbles in the stomach so that gas is more easily belched away. Digestive enzymes, such as lactase supplements, also help by digesting carbohydrates and may allow people to eat foods that normally cause gas. Activated charcoal tablets may provide relief from gas in large intestines.

The doctor may also prescribe medicines to help reduce symptoms, especially in case of motility disorders such as IBS. Drugs such as metoclopramide may move gas through the digestive tract.

Restricting the foods that cause gas such as fruits, vegetables, whole grains and milk products helps. Limiting high-fat foods also may help reducing bloating and discomfort. This helps the stomach empty faster, allowing the gases to move into the small intestines.

How can it be prevented?