Flatulence and Wind

Synonyms of flatulence

Gas, breaking wind, passing gas, bloating, abdominal gas, farting, aerophagia, belching, flatus, intestinal gas.


Flatulence

Flatulence is passing gas from the digestive system out of the back passage. It is more commonly known as ‘passing wind’ or ‘farting’. Farting is often something laughed about, but excessive flatulence may be embarrassing, and it can make people to feel uncomfortable around others. However, it can usually be controlled with changes to people's diet and lifestyle.

Flatulence is a normal biological process and it is something everyone experiences regularly. Some people pass wind only a few times a day, others a lot more, but the average is said to be around 15 times a day.

Why it happens

When people swallow food, saliva or water, they also swallow small amounts of air, that collects in the digestive system. Gases may also build up when people digest their food. The body needs to get rid of the build-up by farting (flatulence) or burping (belching).

Sometimes, people may not notice that they have passed wind, because most of the gases are odorless, and they are often released in small quantities. Flatulence usually only has a bad smell if it contains gases which smell, such as sulphur. However, it is important to remember that it is normal for the gas to sometimes smell a bit.

Excessive flatulence may be caused by swallowing more air than usual or eating food which is difficult to digest. It may also be due to an underlying health problem that affects the digestive system, such as irritable bowel syndrome (IBS).

When to see the Doctor

There are no medical guidelines defining what is the normal frequency or volume of flatulence. Therefore, patients are probably the best person to assess their symptoms. People must see their doctor/ GP, if their flatulence is particularly troublesome (e.g. if they regularly pass smelly gas). They must also visit their doctor if they experience additional symptoms, such as:

• blood in the stools (faeces)
• bowel incontinence
• persistent abdominal pain and bloating
• unexplained weight loss
• change in bowel habit (recurring episodes of diarrhoea or constipation)
• signs of an infection (e.g. high temperature, chills, vomiting, joint pain and muscle pain).

These symptoms could be an indicator of a more serious health problem, and they require investigation, such as a blood or stool test, in order to look for an infection or malignancy.

Controlling the problem

Excessive flatulence can usually be controlled by making changes to the diet and lifestyle, including: 

• exercising regularly
• eating and drinking slowly
• avoiding foods known to cause flatulence
• eating smaller and more frequent meals.

There are also some over-the-counter medications which may help if the flatulence is particularly troublesome, including charcoal tablets or simethicone. If the flatulence is related to an underlying health problem, treating the condition may help resolve the problem.

Causes of flatulence 

There are several natural causes of flatulence. Flatulence may also be caused by some health conditions which are related to the digestive system.

Schematic diagram showing gas in the bowel. When this gas is excreted through the anus, it is known as flatulence. 

Swallowing air

It is perfectly normal for people to swallow air while breathing and eating. However, it is easy to swallow a lot more air than usual without realising it. This may cause excessive flatulence. Excess air can be swallowed by:

• smoking
• chewing gum
• sucking on pen tops or hard sweets
• having loose fitting dentures
• not chewing food slowly and thoroughly (swallowing large pieces of food will result in people swallowing more air).

Hot and fizzy drinks can also increase the amount of carbon dioxide in the stomach, although this is more likely to cause belching rather than flatulence.

Food and drink

Much of the food people eat is carbohydrate. Carbohydrates are made up of long chains of sugar molecules. Some carbohydrates cannot be digested, and they are absorbed by the intestines and pass down into the colon (large bowel). These are known as unabsorbable carbohydrates or fermentable olig-di-mono-saccharides and polyols  (FODMAPs). The colon contains more than 500 different types of bacteria. The bacteria start to break down the carbohydrates and, in the process,  they produce gas, which is released as flatulence.

Foods which contain a high amount of unabsorbable carbohydrates include:

• onions
• cabbage
• apples
• beans
• raisins
• cauliflower
• broccoli
• artichokes
• lentils
• pulses
• prunes
• Brussels sprouts

Other foods and drinks containing a sweetener called sorbitol (e.g. sugar-free gum or slimming products), or a type of sugar called fructose (e.g. fruit juice), may also cause flatulence. Certain foods, such as onions and cabbage, may lead to the production of gases containing sulphur that may result in foul smelling wind. However, the production of smelly wind can vary from person to person, depending on what people eat, so it is up to the individual person to work out which foods cause the most smell.

Health conditions

Health conditions which may cause symptoms of flatulence include:

• malabsorption - where the intestines are unable to absorb nutrients properly
• constipation 
• gastroenteritis - a stomach and bowel infection
• irritable bowel syndrome (IBS) - a common digestive condition, that can cause stomach cramps, bloating, diarrhoea and constipation
• coeliac disease - an intolerance to a protein called gluten, that is found in wheat, rye and barley
• lactose intolerance - where the body is unable to break down lactose (a natural sugar found in milk and dairy products) and it cannot absorb it into the blood.

Treating flatulence 

Excessive flatulence can usually be treated by making changes to the diet and lifestyle. There are also several over-the-counter treatments available, if the flatulence is becoming a problem.

Self-care advice

Diet

People need to avoid eating foods high in unabsorbable carbohydrates. However, it is still important to eat a healthy balanced diet, including at least 5 portions of fruit and vegetables a day. People must choose foods which contain carbohydrates that are easy to digest. These include:

• rice
• bananas
• potatoes
• lettuce
• grapes
• yogurt
• citrus fruits, such as oranges, lemons and grapefruits.

It is important to note that people will react differently to certain foods, so some foods listed above may still cause flatulence. Therefore, patients may find it useful to keep a food diary to see whether certain foods make their symptoms better or worse.

Patients may also find it useful to eat 6 small meals a day, rather than 3 large ones. Smaller meals are easier to digest and they may produce less gas. There is also some evidence to suggest that drinking peppermint tea, may help improve the symptoms of flatulence.

Swallowing air

When eating, people must make sure that they chew their food slowly, in order to reduce the amount of air they are swallowing. This will also help with digestion. They must avoid chewing gum, because it can also cause them to swallow more air than usual. Sugar-free chewing gums also contain chemicals that may cause flatulence.

Patients must also give up smoking, if they smoke. Smoking may cause them to swallow more air than usual, and tobacco smoke may irritate their digestive system.

Exercise

Getting plenty of exercise may help improve the functioning of the digestive system and bowel. It has also been shown to help with bloating and the passage of gas.

Medications and other remedies

There are several over-the-counter remedies which can help treat symptoms of flatulence, some of which include:

Charcoal tablets

Charcoal tablets are a type of medication available over the counter from pharmacists. The charcoal absorbs gas in the digestive system, and therefore helps reduce the symptoms of flatulence. Charcoal tablets may not be suitable for patients who are taking other medications. This is because the charcoal might absorb the medication and make it less effective. 

If a patient is taking any other medications, they must consult their doctor or pharmacist for advice before taking charcoal tablets. Clothing containing activated charcoal, or charcoal pads placed inside clothing, may help absorb foul-smelling gas released during flatulence. These products can be purchased online. Simethicone is another over-the-counter medication which can sometimes help with gas problems.

Dietary supplements

Alpha-galactosidase is a dietary supplement which may help improve the digestion of carbohydrates and therefore reduce symptoms of flatulence. It is found in a product called 'Beano', that has been shown to have some effect in reducing flatulence, and it is available from some pharmacists and health food shops.

Probiotics may also be useful in treating flatulence. Probiotics are a dietary supplement, usually sold in liquid or capsule form, that encourage the growth of 'friendly bacteria' in the digestive system. The 'friendly bacteria' help digestion, and therefore reduce the symptoms of flatulence, especially in people with irritable bowel syndrome (IBS).

Flatulence (Gas) Overview

Flatulence is the state of having excessive stomach or intestinal gas. This may result in uncomfortable feelings of bloating, as well as increased belching (burping) or passing of gas from the rectum. Most people produce about 1-3 pints of gas a day, and pass gas about 14 times a day. Flatulence itself, although it is not life-threatening, it can definitely cause social embarrassment. This embarrassment is often the reason why people might seek medical help for excessive gas.

History has numerous anecdotal accounts of flatulence, including Hippocrates himself professing: "Passing gas is necessary to well-being." The Roman Emperor Claudius equally decreed that: "all Roman citizens shall be allowed to pass gas whenever necessary." 

In the mid-1800s flatulence took center stage with the French entertainer Joseph Pugol ("Le Petomane"). Pugol was able to pass gas at will and at varying pitch, thereby playing tunes for sold-out shows at the Moulin Rouge.

More recently, flatulence was immortalized by Mel Brooks in the movie "Blazing Saddles" with his bean-eating cowboys. 

If a person is concerned about excess gas, it is not a laughing matter. It is a medical concern that individual's will want to talk about with a health care professional.  The primary components of gas (known as flatus) are five odorless gases: nitrogen, hydrogen, carbon dioxide, methane, and oxygen. The characteristic smelly odor is attributed to trace gases such as skatole, indole, and sulfur-containing compounds.

The flammable character of flatus is caused by hydrogen and methane. The proportions of these gases depend largely on the bacteria which live in the human colon that digest, or ferment, food which has not been absorbed by the gastrointestinal (GI) tract before reaching the colon. An estimated 30-150 grams of this undigested food reach the colon in the form of carbohydrate every day. But this amount may vary with diet, and how well the GI tract is functioning.

Flatulence (Gas) Causes

Excess gas in the digestive tract (oesophagus, stomach, small intestine, and colon/ large intestine) can come from 2 sources: 

• increased intake of gas (e.g. from air swallowed); or 
• increased production of gas as certain undigested foods are broken down by harmless bacteria normally found in the colon.

Swallowed air (aerophagia): This may occur with improper swallowing while eating or even unconscious swallowing of air out of habit. Activities which cause a person to swallow air include hyperventilation, rapid drinking, chewing gum, use of tobacco products, loose dentures, sucking on hard candy, and drinking carbonated beverages. 

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).

Breakdown of undigested foods: If the body does not digest and absorb some carbohydrates (e.g. 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 (colon), 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 which produce gas in one person may not cause gas in another. Some common bacteria in the large intestine can destroy the hydrogen which other bacteria produce. The balance of the two types of bacteria may explain why some people have more gas than others. Most foods which contain carbohydrates can cause gas. By contrast, fats and proteins cause little gas. These common foods and their natural components may create gas:

• Beans: 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.
• Red wine and dark beer.
• Onions: 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.
• Starches: Most starches (potatoes, corn, noodles, and wheat) produce gas as they are broken down in the large intestine. Rice is the only starch which does not cause gas.
• Sorbitol: This sugar is found naturally in fruits including apples, pears, peaches, and prunes. It is 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 (colon), 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.
• Lactase deficiency: Another major source of flatulence is lactase deficiency, which results in a decreased ability to digest lactose, a natural sugar found in milk and other dairy products (e.g. cheese and ice cream) and in certain processed food (e.g. bread, cereal, and salad dressing). This flatulence is often associated with diarrhoea and cramping, but it may appear as only gas. Many people  normally have low levels of the enzyme lactase needed to digest lactose after childhood. Also, as people get older, their enzyme levels decrease. As a result, over time people may experience increasing amounts of gas after eating food containing lactose.
• Other problems: Certain conditions may result in other foods being poorly absorbed in the gastrointestinal 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. 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 may follow.
• Alterations in bowel habits can be a result of the following:
• Parasites
• Poor thyroid function (hypothyroidism)
• Poor dietary fiber
• Inflammatory bowel disease (IBD) (Crohn's or Ulcerative Colitis)
• Intestinal obstruction (including cancer)
• Diverticulosis or diverticulitis
• Narcotic and other drug use

Flatulence (Gas) Symptoms

Symptoms of 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 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 belchs 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 can cause bloating, such as irritable bowel syndrome (IBS), 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 their 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.

When to Seek Medical Care

Visiting a health care professional is the best place to start. Seek medical attention whenever symptoms other than simply excess flatulence occur, such as:

• Fever
• Nausea (feeling sick)
• Diarrhoea
• Severe crampy abdominal discomfort
• Change in bowel habits
• Constipation
• Blood in the stool
• Vomiting
• Abdominal pain and swelling, especially in the right lower part of the abdomen (tummy).

Flatulence (Gas) Diagnosis

A health care professional may review what patient eats and the symptoms produced. Peole might 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 can 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 a food intolerance, with the bacteria fermenting the undigested food to produce excess gas. After the patient eats a problem food, breath testing must 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, more broad testing can be accomplished to help exclude more serious disorders such as diabetes, cancer, malabsorption, liver cirrhosis, poor thyroid function (hypothyroidism), and infection.

If a patient has abdominal pain or appears to have a swollen abdomen, the doctor may have X-rays taken to show intestinal obstruction or perforation. X-rays may also be taken after the patient drinks X-ray dye to show the GI tract, that 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 doctor can suggest to the patient to avoid milk products for a period of time. A blood or breath test may be used to diagnose lactose intolerance.

Flatulence (Gas) Treatment

The most common ways to reduce the discomfort of gas are changing diet, taking medicines, and reducing the amount of air swallowed.

Flatulence (Gas) Self-Care at Home

Flatulence is most often related to diet, and sometimes to those habits which cause a person to swallow air. Patients must start by trying to remove problem foods from their diet. For many people, this is a trial-and-error procedure.

This may take careful observation to notice what foods cause increased gas. Patients must keep a food diary and note excess passage of gas. Any of the gas-producing foods can be removed from the diet one group at a time, until the person experiences relief. Sorbitol and fructose are common offenders, so patients should try these first.

If this method does not work, a more restrictive approach is for patients to start with a very limited number of safe foods, and add one new food every 48 hours in order to determine what food or food group causes difficulty. If the offending food is found, then the affected person can avoid eating that food, or be prepared for its consequences.

If lactose intolerance is suspected to cause the problem, patients should remove all dairy foods from the diet for 10-14 days to assess the effect on flatulence (using a diary). The enzyme lactase, which aids with lactose digestion, is available in liquid and tablet form without a prescription (Lactaid, Lactrase, Dairy Ease). Adding a few drops of liquid lactase to milk before drinking it or chewing lactase tablets just before eating helps digest foods which contain lactose. Also, lactose-reduced milk and other products are available at many grocery stores (Lactaid, Dairy Ease).

If odor is a concern, there is also some reported success with charcoal filter undergarments.

·         If belching is a problem, avoid the behaviors that cause the affected person to swallow air, such as chewing gum or eating hard candy. Eat slowly. Make sure dentures fit properly.

·         In general, avoid overeating because this contributes to flatulence as well asobesity. Limit high-fat foods to reduce bloating and discomfort. The stomach will empty faster, allowing gases to move into the small intestine.

Flatulence (Gas) Medical Treatment

The goal of treatment of flatulence is to reduce gas and smelly odor. Medical intervention includes treatment with antibiotics if bacterial overgrowth of the GI tract is suspected or evidence of parasitic infection is seen.

·         Some promising studies have investigated feeding nonoffensive strains of bacteria to push out the bacteria that are offensive, although no established treatments are available at this time.

·         Regulation of bowel function is essential. Constipation should be treated with increased dietary fiber or certain laxatives.

·         In cases where anxiety causes the person to swallow air, the doctor may suggest he or she seek mental health counseling to change habit patterns.

Flatulence (Gas) Medications

If the patient does not desire to avoid the foods that cause gas, many nonprescription medicines are available to help reduce symptoms.

·         Beano is an enzyme supplement that may be useful with bean ingestion. It contains the sugar-digesting enzyme that the body lacks to digest the sugar in beans and many vegetables. Beano has no effect on gas caused by lactose or fiber. Beano can be purchased over-the-counter. Add 3-10 drops per serving just before eating beans and vegetables to break down the gas-producing sugars during digestion.

·         Antacids, such as Mylanta II, Maalox II, and Di-Gel, contain simethicone, a foaming agent that joins gas bubbles in the stomach so that gas is more easily belched away. However, these medicines have no effect on intestinal gas. These can be taken before meals. Dosage varies.

·         Activated charcoal tablets (Charcocaps) may provide relief from gas in the colon. Gas can be reduced if tablets are taken before and after a meal. The usual dose is 2-4 tablets taken just before eating and one hour after meals.

·         Certain prescription medicines may help reduce symptoms, especially if you have a disorder such as irritable bowel syndrome. Some medicines such asmetoclopramide (Reglan) have also been shown to decrease gas complaints by increasing gut activity.

Flatulence and wind are symptoms related to gas in the gastrointestinal (GI) system. 'Flatulence' usually refers to gas passed per rectum. 'Wind' as a symptom may mean either belching (gas passed from the stomach outwards via the mouth) or gas passed per rectum (or even just feeling bloated). 'Eructation' is another term for belching.

Flatulence and belching are common symptoms in the general population.

Normal physiology

Belching

·         This is the release of gas from the stomach, either voluntary or involuntary. It is a normal reflex which occurs most commonly after meals, releasing swallowed air.

·         There may be two types of excessive belching:

·         Supragastric belching, where air is sucked into and expelled from the pharynx only.

·         Aerophagia, where there is excess swallowing of air into the stomach.

Flatulence

·         Intestinal bacterial colonies produce gases. Carbon dioxide, hydrogen and methane are responsible for the main volume of intestinal gas and sulfur-containing gases for malodour.

·         The volume and composition of gas depends both on diet and on colonic flora.

·         Peope with irritable bowel syndrome (IBS) are likely to produce a greater volume of gas than people who do not have IBS. IBS is also associated with a positive lactulose breath test (a test that assesses the amount of fermented gas generated by bacteria in the bowel) and an increase in gas-related symptoms. This would seem to counteract previous theories that there is no difference in the amount of gas produced by IBS and non-IBS individuals but that non-IBS people are simply more tolerant of large gas volumes.

Aetiology

Belching

·         Diet/lifestyle factors - eg, eating too quickly, fizzy drinks, chewing gum, smoking.

·         Antacids - produce carbon dioxide gas which may contribute.

·         Dyspepsia or reflux - patients may swallow air and may belch in an attempt to relieve upper GI symptoms.

·         Giardiasis - can cause malodorous belching.

Flatulence

Symptoms may be due to excessive volume of gas or to malodour. Possible causes or contributing factors are:

·         Diets high in fermentable carbohydrate (eg, pulses, bran and fruit).

·         Variations in bowel flora composition.

·         Constipation

·         IBS.

·         Acute gastroenteritis.

·         Giardiasis.

·         Small intestinal bacterial overgrowth.

·         Lactose intolerance.

·         Malabsorption.

·         Flatulence (and belching) are common in female runners. The cause for this has yet to be elucidated.

Assessment

·         Clarify what most bothers the patient about their symptoms.

·         'Red flags' - eg, dysphagia, weight loss, rectal bleeding, change in bowel habit with looser stools in patients aged >60, family history of bowel cancer.^[14]

·         Clinical examination (if relevant) to look for any serious signs - eg, anaemia, nodes and abdominal, pelvic or rectal masses.

Investigations

These depend on the clinical picture. Basic tests may be relevant to help rule out other problems (eg, as recommended in the diagnosis of irritable bowel syndrome):

·         FBC.

·         ESR or CRP.

·         Antibody testing for coeliac disease.

Breath tests may be used to assess intestinal flora and small intestinal bacterial overgrowth, usually in the context of research studies.

Management

Belching

·         Explanation of normal physiology and reassurance may be sufficient.

·         Investigate/treat dyspepsia and reflux symptoms if relevant.

·         Speech therapy or behavioural therapy may be used.

Flatulence

Note that most of the research and literature on this topic relates to patients diagnosed with IBS. Possible treatments are:

·         Mild physical activity - has been shown to enhance gas clearance in a study of patients with bloating.

·         Treating exacerbating factors such as constipation.

·         Diet:

·         Soluble fibre such as linseed (up to one tablespoon daily) and oats.

·         Diets low in fermentable carbohydrate can reduce flatulence in IBS.

·         Probiotics:

·         These are 'gut-friendly' bacteria such as lactobacilli and bifidobacteria.

·         Their mechanism of action is unclear but they can alter colonic fermentation and inhibit gas-producing bacteria such as Clostridium spp. They have an effect on intestinal motility and may also have an anti-inflammatory effect on mucosal cells.

·         They have been shown to reduce flatulence in patients with IBS.

·         The specific strain of bacteria may be important but, on current evidence, it is difficult to advise which strain(s) to use.

·         Drugs:

·         Antibiotics (eg, metronidazole or rifaximin) can be used to treat small intestinal bacterial overgrowth. One study reported that rifaximin was more effective and better tolerated than metronidazole.

·         Simeticone combined with loperamide may improve gas symptoms in acute diarrhoea. Neither simeticone nor activated charcoal has a beneficial effect in IBS-related gas symptoms.

·         Oral bismuth subsalicylate binds sulfide gases in the gut but is not safe for regular use due to the salicylate content.

·         Supplements:

·         Alpha-galactosidase, an enzyme supplement, has been shown to reduce flatus after eating beans. One study reported that it is particularly effective in children.

·         Odour reduction devices:

·         Garment devices containing activated charcoal have been tested in one trial. This found that briefs containing charcoal were effective, but pads and cushions of the same material were less helpful.

Source: NHS Choices.