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Symptoms and Signs of Flatulence (Gas)

Doctor's Notes on Flatulence (Gas)

Flatulence refers to the presence of excess intestinal gas that is released from the anus with sound and/or odor. The excess gas is a byproduct of digestion within the intestine when bacteria normally present in the gut work to break down ingested foods. Swallowing air due to eating or drinking too rapidly, lactose intolerance, and maldigestion of certain foods can contribute to gas formation.

Symptoms of flatulence include excess or increased frequency of passing of gas from the anus. Associated signs and symptoms increased frequency or excessive instances of passing gas,¬†foul-smelling gas, abdominal pain or cramping, and belching. Some people may also experience abdominal bloating, or the sensation that the abdomen is larger, and a feeling that has been described as “knots” in the stomach.

Medical Author:
Medically Reviewed on 3/11/2019

Flatulence (Gas) Causes

Signs and symptoms of excessive flatulence are increased passage of gas, and abdominal bloating or pain, and belching. Embarrassment can be caused by the increased passage of flatus or the often-offensive odor it causes.

  • Gas: Everyone passes gas (flatulate) normally each day. A certain amount of gas is present in the GI tract at any one time, mainly in the stomach and colon. The average person passes gas about 10 times each day and up to 20-25 times is considered normal. More than that may be excessive.
  • Belching: An occasional belch during or after meals is normal and releases gas when the stomach is full of food. But if a person belches frequently, he or she may be swallowing too much air and releasing it before the air enters the stomach. Some people swallow air to make themselves belch, thinking it will relieve their discomfort. This practice may turn into an annoying habit. Belching may signal a more serious upper GI disorder such as peptic ulcer disease, gastroesophageal reflux disease (GERD), or gastroparesis.
  • Abdominal bloating: Many people believe that too much gas causes abdominal bloating. However, people who complain of bloating from gas often have normal amounts of gas. They actually may be unusually aware of gas in the digestive tract. A diet of fatty foods may delay stomach emptying and cause bloating and discomfort, but not necessarily too much gas. Certain conditions may cause bloating, such as irritable bowel syndrome, Crohn's disease, or colon cancer. People with scar tissue (adhesions) from abdominal operations or internal hernias may have a sensation of bloating because of increased sensitivity to gas.
  • Abdominal pain and discomfort: Some people have pain when gas is present in the intestine. When pain is on the left side of the colon, it can be confused with heart disease. When the pain is on the right side of the colon, it may mimic gallstones or appendicitis.

Excess gas in the digestive tract (esophagus, stomach, small intestine, and colon/large intestine) can come from two sources: 1) increased intake of gas, for example, from air swallowed; or 2) increased production of gas as certain undigested foods are broken down by harmless bacteria normally found in the colon. Undigested foods may also occur in chronic intestinal problems such as chronic megacolon, patients undergoing chemotherapy or in certain infectious diseases such as giardiasis.

Swallowed air

Swallowed air (aerophagia) can occur with improper swallowing while eating or even unconscious swallowing of air out of habit.

  • Activities that cause a person to swallow air include rapid drinking, chewing gum, use of tobacco products, sucking on hard candy, drinking carbonated beverages, loose dentures, and hyperventilation
  • Most people burp or belch to expel this excess swallowed air. The remaining gas moves into the small intestine. The air moves along to the large intestine for release through the rectum.
  • Analysis of the gas can help determine if it originated from aerophagia (mostly nitrogen, also oxygen, and carbon dioxide) or GI production (mainly carbon monoxide, hydrogen, and methane).

Lactase intolerance

Another major source of flatulence is lactose intolerance, which results in a decreased ability to digest lactose, a natural sugar found in milk and other dairy products such as cheese and ice cream and in certain processed food such as bread, cereal, and salad dressing. This flatulence is often associated with diarrhea and cramping but can appear as only gas. Many people normally have low levels of the enzyme lactase needed to digest lactose after childhood. Also, as people age, their enzyme levels decrease. As a result, over time people may experience increasing amounts of gas after eating food containing lactose, and develop chronic flatulence with gas pain(s). One way to remedy gas pain or get gas pain relief is avoiding foods that contain lactose.

Certain conditions can result in other foods being poorly absorbed in the gastrointestinal (GI) tract, allowing for increased bacterial activity.

  • Malabsorption syndromes can be the result of decreased production of enzymes by the pancreas or problems with the gallbladder or lining of the intestines.
  • SIBO (small intestinal bacterial overgrowth) is a condition in which there is an increase in the number and/or alteration of the bacterial types in the upper gastrointestinal track that may result in bloating, flatulence, abdominal and/or gas pain discomfort and diarrhea. The syndrome is usually associated with small intestinal motility disorders, and is treated with antibiotics.
  • If transit through the colon is slowed down for any reason, bacteria have increased opportunity to ferment remaining material. If a person is constipated or has decreased bowel function for any reason, flatulence can develop.
  • Alterations in bowel habits can be a result of the following:

Certain conditions can result in other foods being poorly absorbed in the gastrointestinal (GI) tract, allowing for increased bacterial activity.

  • Malabsorption syndromes can be the result of decreased production of enzymes by the pancreas or problems with the gallbladder or lining of the intestines.
  • SIBO (small intestinal bacterial overgrowth) is a condition in which there is an increase in the number and/or alteration of the bacterial types in the upper gastrointestinal track that may result in bloating, flatulence, abdominal and/or gas pain discomfort and diarrhea. The syndrome is usually associated with small intestinal motility disorders, and is treated with antibiotics.
  • If transit through the colon is slowed down for any reason, bacteria have increased opportunity to ferment remaining material. If a person is constipated or has decreased bowel function for any reason, flatulence can develop.
  • Alterations in bowel habits can be a result of the following:

A health-care professional may review what patient eats and the symptoms produced. The patient might be instructed to keep a food and drink diary for a specific period of time and track the passage of gas during the day. Careful review of diet and the amount of gas passed may help relate specific foods to symptoms and determine the severity of the problem.

The primary tests, if necessary, will likely include measuring the amount of hydrogen in the patient's breath after the person eats suspected foods. Because bacteria are largely responsible for the production of hydrogen, an increase in exhaled hydrogen as measured by the breath test will suggest food intolerance, with the bacteria fermenting the undigested food to produce excess gas. After the patient eats a problem food, breath testing should show an increase in hydrogen in as little as 2 hours.

Another possible test is analysis of flatus for gas content. This should help differentiate gas produced by swallowing air from gas produced in the gastrointestinal (GI) tract.

If these tests produce no diagnosis, broader testing can be accomplished to help exclude more serious disorders such as diabetes, cancer, malabsorption, cirrhosis of the liver, poor thyroid function, and infection.

If a patient has abdominal pain or appears to have a swollen abdomen, the health-care professional may have X-rays taken to show intestinal obstruction or perforation. X-rays can also be taken after the patient drinks X-ray dye to show the GI tract, which can be followed up with an internal view of the colon through colonoscopy, if problems are noted.

If lactase deficiency is the suspected cause of gas, the health-care professional may suggest the patient avoid milk products for a period of time. A blood or breath test may be used to diagnose lactose intolerance.

A health-care professional may review what patient eats and the symptoms produced. The patient might be instructed to keep a food and drink diary for a specific period of time and track the passage of gas during the day. Careful review of diet and the amount of gas passed may help relate specific foods to symptoms and determine the severity of the problem.

The primary tests, if necessary, will likely include measuring the amount of hydrogen in the patient's breath after the person eats suspected foods. Because bacteria are largely responsible for the production of hydrogen, an increase in exhaled hydrogen as measured by the breath test will suggest food intolerance, with the bacteria fermenting the undigested food to produce excess gas. After the patient eats a problem food, breath testing should show an increase in hydrogen in as little as 2 hours.

Another possible test is analysis of flatus for gas content. This should help differentiate gas produced by swallowing air from gas produced in the gastrointestinal (GI) tract.

If these tests produce no diagnosis, broader testing can be accomplished to help exclude more serious disorders such as diabetes, cancer, malabsorption, cirrhosis of the liver, poor thyroid function, and infection.

If a patient has abdominal pain or appears to have a swollen abdomen, the health-care professional may have X-rays taken to show intestinal obstruction or perforation. X-rays can also be taken after the patient drinks X-ray dye to show the GI tract, which can be followed up with an internal view of the colon through colonoscopy, if problems are noted.

If lactase deficiency is the suspected cause of gas, the health-care professional may suggest the patient avoid milk products for a period of time. A blood or breath test may be used to diagnose lactose intolerance.

If the body does not digest and absorb some carbohydrates (for example, the sugar, starches, and fiber found in many foods) in the small intestine because of a shortage or absence of certain enzymes there, this undigested food then passes from the small intestine into the large intestine, where normal, harmless bacteria break down the food, producing hydrogen, carbon dioxide, and, in about a third of all people, methane. Eventually these gases exit through the rectum.

Foods that may cause acute and/or chronic constant flatulence or gas include:

  • 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.
  • Most foods that contain carbohydrates can cause gas. By contrast, fats and proteins cause little gas. These common foods and their natural components may create gas:
    • Raffinose: Beans contain large amounts of the complex sugar known as raffinose. Smaller amounts are found in cabbage, Brussels sprouts, broccoli, asparagus, and in other vegetables and whole grains.
    • Starches: Most starches (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.
    • Fructose: The sugar known as fructose occurs naturally in onions, artichokes, pears, and wheat. It is also used as a sweetener in some soft drinks and fruit drinks.
    • Dark beer and red wine
    • Sorbitol: This sugar is found naturally in fruits including apples, pears, peaches, and prunes. It's also used as an artificial sweetener in sugar-free gum, candy, and other diet products.
    • Fiber: Many foods contain soluble and insoluble fiber. Soluble fiber dissolves easily in water and takes on a soft, gel-like texture in the intestines. Found in oat bran, beans, peas, and most fruits, soluble fiber is not broken down until it reaches the large intestine, where digestion causes gas. 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 fiber.

If the body does not digest and absorb some carbohydrates (for example, the sugar, starches, and fiber found in many foods) in the small intestine because of a shortage or absence of certain enzymes there, this undigested food then passes from the small intestine into the large intestine, where normal, harmless bacteria break down the food, producing hydrogen, carbon dioxide, and, in about a third of all people, methane. Eventually these gases exit through the rectum.

Foods that may cause acute and/or chronic constant flatulence or gas include:

  • 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.
  • Most foods that contain carbohydrates can cause gas. By contrast, fats and proteins cause little gas. These common foods and their natural components may create gas:
    • Raffinose: Beans contain large amounts of the complex sugar known as raffinose. Smaller amounts are found in cabbage, Brussels sprouts, broccoli, asparagus, and in other vegetables and whole grains.
    • Starches: Most starches (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.
    • Fructose: The sugar known as fructose occurs naturally in onions, artichokes, pears, and wheat. It is also used as a sweetener in some soft drinks and fruit drinks.
    • Dark beer and red wine
    • Sorbitol: This sugar is found naturally in fruits including apples, pears, peaches, and prunes. It's also used as an artificial sweetener in sugar-free gum, candy, and other diet products.
    • Fiber: Many foods contain soluble and insoluble fiber. Soluble fiber dissolves easily in water and takes on a soft, gel-like texture in the intestines. Found in oat bran, beans, peas, and most fruits, soluble fiber is not broken down until it reaches the large intestine, where digestion causes gas. 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 fiber.

The following is a list of foods, drinks and other items that may be associated with chronic, constant, extreme, and/or increased flatulence and/or gas pains in certain individuals:

  • Milk and other dairy products
  • Beans
  • Sodas
  • Hard candy
  • Lentils
  • Wheat
  • Potatoes
  • Pasta
  • Oat bran
  • Apples
  • Peaches
  • Pears
  • Bananas
  • Apricots
  • Melons
  • Prunes
  • Raisins
  • Broccoli
  • Brussels sprouts
  • Corn
  • Peas
  • Onions
  • Shallots
  • Chewing gum
  • Cauliflower

The following is a list of foods, drinks and other items that may be associated with chronic, constant, extreme, and/or increased flatulence and/or gas pains in certain individuals:

  • Milk and other dairy products
  • Beans
  • Sodas
  • Hard candy
  • Lentils
  • Wheat
  • Potatoes
  • Pasta
  • Oat bran
  • Apples
  • Peaches
  • Pears
  • Bananas
  • Apricots
  • Melons
  • Prunes
  • Raisins
  • Broccoli
  • Brussels sprouts
  • Corn
  • Peas
  • Onions
  • Shallots
  • Chewing gum
  • Cauliflower

Digestive Health Why Am I Bloated? Slideshow

Digestive Health  Why Am I Bloated? Slideshow

Distended abdomen, feeling like you ate too much, feeling like you are full of excessive gas. What causes these symptoms? There are many reasons for a swollen belly that feels too full. Several health conditions including irritable bowel syndrome, acid reflux, and celiac disease may cause it. Certain foods and beverages may also lead to the uncomfortable symptom. Often, bloating is not a cause for concern. Other times it may be a sign of something potentially more serious. The underlying causes of bloating are varied. Read on to discover what may be causing your symptoms.

REFERENCE:

Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.

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