What is Flatulence?
Everyone has gas and eliminates it by burping or passing it through the rectum. However, many people think they have too much gas when they really have normal amounts. Most people produce pass gas about 14 times a day with a volume from about 500 to 1500 mL per day.
Gas is made primarily of odorless vapors-carbon dioxide, oxygen, nitrogen, hydrogen, and sometimes methane. Offensive odors, when present, may be due to sulfur-containing compounds, as well as short-chain fatty acids. Although having gas is common, it can be uncomfortable and embarrassing. Understanding causes, ways to reduce symptoms, and treatment will help most people find relief.
What causes gas?
Gas in the digestive tract comes from two sources:
> swallowed air
> normal breakdown of certain undigested foods by bacteria naturally present in the large intestine (colon)
Air swallowing (aerophagia) is a common cause of gas in the stomach. Everyone swallows small amounts of air when eating and drinking. However, eating or drinking rapidly, chewing gum, smoking, or wearing loose dentures can cause some people to take in more air.
Burping is the way most swallowed air leaves the stomach. The remaining gas moves into the small intestine, where it is partially absorbed with a small amount reaching the large intestine and being passed as flatus.
Breakdown of Undigested Foods
Some sugars, carbohydrates and fibre are not metabolized by the small bowel and pass into the large colon (bowel). In the large bowel the bacteria present breakdown the remaining food stuff which produces hydrogen, carbon dioxide, and, in about one-third of all people, methane.
People who make methane do not necessarily pass more gas or have unique symptoms. A person who produces methane will have stools that consistently float in water. Research has not shown why some people produce methane and others do not.
Foods that produce gas in one person may not cause gas in another. Some common bacteria in the large intestine can destroy the hydrogen that other bacteria produce. The balance of the two types of bacteria may explain why some people have more gas than others.
Which foods cause gas?
Most foods that contain carbohydrates can cause gas. By contrast, fats and proteins cause little gas.
The sugars that cause gas are raffinose, lactose, fructose, and sorbitol.
Beans contain large amounts of this complex sugar. Smaller amounts are found in cabbage, brussels sprouts, broccoli, asparagus, other vegetables, and whole grains.
Lactose is the natural sugar in milk, and products produced from milk. People from Asian or African backgrounds may have a heightened sensitivity to lactose due to lower levels of the enzyme required to digest it.
Fructose is naturally present in onions, artichokes, pears, 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 dietetic foods and sugarfree lollies & gums.
Most starches, including potatoes, corn, noodles, and wheat, produce gas as they are broken down in the large intestine. Rice is the only starch that does not cause gas.
Many foods contain soluble and insoluble fibre. Soluble fibre is found in oat bran, beans, peas, and most fruits. Soluble fibre is broken down in the large intestine leading to gas production. Insoluble fiber, on the other hand, passes essentially unchanged through the intestines and produces little gas. Wheat bran and some vegetables contain this kind of fibre.
What are some symptoms and problems of gas?
The most common symptoms of gas are flatulence, abdominal bloating, abdominal pain, and belching. However, not everyone experiences these symptoms. The determining factors probably are how much gas the body produces, how many fatty acids the body absorbs, and a person’s sensitivity to gas in the large intestine.
An occasional belch during or after meals is normal and releases gas when the stomach is full of food. However, people who belch frequently may be swallowing too much air and releasing it before the air enters the stomach.
Sometimes a person with chronic belching may have an upper GI disorder, such as peptic ulcer disease (Hyperlink), gastro-oesophageal reflux disease(GORD), or gastroparesis.
Occasionally, some people believe that swallowing air and releasing it will relieve the discomfort of these disorders, and this person may intentionally or unintentionally develop a habit of belching to relieve discomfort.
How is gas treated?
Experience has shown that the most common ways to reduce the discomfort of gas are changing diet, taking medicines, and reducing the amount of air swallowed.
A modified diet as suggested by a dietician may help. However, for some people this may mean cutting out healthy foods, such as fruits and vegetables, whole grains, and milk products.
There are a number of medications which may help with gas; including simethicone (Infacol) and charcoal tablets.