What causes Flatulence?

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Trapped wind and flatulence happen to most people at some point, but it can sometimes be a little awkward. Here is how to keep your gas under control.

It is normal to pass wind every now and then, but when it happens frequently it can undermine your confidence.

During digestion, chemicals called enzymes bread down foods so they can be absorbed in the small intestine. During this process, some undigested sugars, starches and fibres reach the large intestine. There, they ferment as bacteria in the gut to try and break them down. This can cause discomfort and trapped wind, but what causes flatulence and how can we reduce the symptoms of it?Women suffering from flatulence

What is Flatulence?

Flatulence is passing gas from the digestive out of the back passage. Its more commonly known as “passing wind”, or “farting”.  Flatulence is a medical term for releasing gas from the digestive system. It happens when gas collects inside the digestive system, and is a normal process.

Farting is often laughed about, but excessive flatulence can be embarrassing and make you feel uncomfortable around others. However, it can normally be controlled by making slight changes in your diet and to your lifestyle.

It’s important to remember that flatulence is a normal biological process and 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 about 5 to 15 times a day.

Some conditions like irritable bowl syndrome, celiac disease, and gastroparesis can cause excessive flatulence. You may also pass wind more frequently depending on the foods you eat, in some cases, gas can cause pain and bloating, which may affect your daily activities. Adjusting your diet, taking medications, and exercising may help reduce gas discomfort.

Loud Wind

Loud wind is produced by powerful contractions of the bowel wall forcing gas through a narrow anus. The muscle at the bottom of the rectum that keeps the intestinal contents on their place. Measures to reduce production may help to lessen the symptoms.

Smelly Wind

This is causes by smelly chemicals like indoles, skatoles and hydrogen sulphide that are produced by bacterial fermentation in the colon. Garlic and onions, many spices and some herbs of the fennel family, particularly asafoetida, which are mainly used in Indian cooking, produce smelly gases.

Beer, white wine and fruit juices give rise to smelly hydrogen sulphide in some people. Some of these smelly gases are absorbed into the blood stream and excreted in the breath as well. Reducing the intake of these substances may relieve symptoms. Eating a lot of fatty foods can cause smelly wind, and it is worth cutting down on fat if this is a particular problem.

What causes Flatulence?

Gas collects in two main ways. Swallowing air whilst eating or drinking, which can cause oxygen and nitrogen to collect in the digestive tract. Second, as your body breaks down food, gases like hydrogen, methane and carbon dioxide collect in the digestive tract, either method can result in flatulence. A normal individual passes wind on average 5-15 times per day, depending on diet.

Many factors cause the passing of wind, from your genes to an underlying condition. However, you can reduce unwanted wind problems, the first step is to identify the source of the problem, here are some of the main causes of flatulence:Fast Food

A High Fibre Diet

This produces more wind than a low fibre diet or a low carbohydrate diet. It is possible to reduce flatus production, even on a high fibre diet, by avoiding the big gas producers which contain certain carbohydrates called oligosaccharides. These cannot be digested in the small intestine but are like food to bacteria in the colon, there are many foods that cause bloating and produce a lot of gas in the colon; these should be avoided if giving you severe wind.

Lactose Intolerance

Some otherwise healthy people lack the enzyme necessary to digest lactose, the sugar that can be found in cow’s milk. As a result, the lactose is fermented in the colon bacteria with the production of large amounts of carbon dioxide and hydrogen, which may cause gas as well as abdominal cramps. Reducing your intake of milk to which symptoms are controlled, can reduce the flatulence.

Eating or Drinking too Quickly

The process of this makes us swallow air, which is then released as burps and belches. Swallowing air, or aerophagia, can also be caused by chewing gum, smoking, having a blocked nose and wearing dentures that don’t fit properly. It is common to experience trapped wind after eating.


Such as xylitol and sorbitol, which are commonly used in reduced-calorie drinks, chewing gums, sweets, cakes and biscuits all cause flatulence. This is because we lack the enzymes needed to digest them.


This is a fruit sugar found in table sugar, sweeteners and syrups, dried fruits, juices and other processed foods and drinks. Our bodies can’t digest too much fructose at one time, and it can build up quickly in our bodies.

An apple, or a 200ml glass of orange juice, both have around 6g of fructose and some carbonated drinks have up to 50g for a single can or bottle. Undigested fructose reaches the large intestine, where it ferments and produces gas.


Medicines such as, ibuprofen, statins and antifungals can sometimes cause flatulence. Speak to your doctor if you suspect a medicine you take regularly is causing wind problems.

Gut Bacteria

This plays a key role in digestion. Around 500 different bacteria species are found in the large intestine and everyone’s microbiome, is unique. As bacteria interact with the undigested carbohydrates in the gut, they produce a range of different gases and these can lead to excessive wind and flatulence.

The microbiome is influenced by our diet, lifestyle and use of antibiotics can lead to significant changes in the gases we produce. That is why, sometimes, antibiotics can cause flatulence, and why probiotics, which contain friendly bacteria, can improve the balance of beneficial bacteria and reduce flatulence and other gastric symptoms.

A Few Simple Steps to Reduce flatulence

Excessive flatulence can usually be controlled by making changes to your diet and lifestyle, such as avoiding foods known to cause flatulence, eating smaller and more frequent meals and exercising regularly. There are also some over-the-counter medications that can help if your flatulence is troublesome, such as charcoal tablets or simethicone. Other ways to stay on top of it could be:Family Cycling

Keep a food diary

This is a good way to note down what foods you have eaten throughout the day and help you to identify what foods are causing flatulence, and therefore you can avoid them.

Eat smaller meals, more often

This gives the amylase in saliva more time to start breaking down carbohydrates which can help prevent excess wind, along with this try and chew your food slowly too.

Drink plenty of water

Drinking plenty of water helps reduce the risk of constipation and keeps things moving through the intestines.

Exercise to improve digestion

There has been evidence to show that light exercise, such as walking or gentle bike rides, will reduce symptoms of flatulence. It is believed that exercise helps matter move through the intestine so it may aid constipation too.

Check your fibre intake

Most of us don’t eat enough fibre. Around 30g a day is recommended. Fruits, vegetables and whole grains such as wholemeal bread, oats and quinoa are great sources.

If you feel as though your flatulence may be due to an underlying health condition, then you should always seek the help and advice of a trusted health professional.

Now that you know what causes flatulence and how to simply avoid excessive flatulence, learn more about the digestive system and read our article 9 remedies for indigestion that might really work, next.

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