Health Check: The ins and outs of burping and farting

by Terry Bolin, The Conversation
About 40% of people produce smelly gas because of a certain bacteria in their bowels. Credit: HyoJung Kim, CC BY-NC

To understand why we fart, you need to know something about the volume of gases produced in the bowels first.

Imagine how much space 25 litres of gas would occupy – about one third of the interior of a small car. That's how much gas you produce every day in your . So it's little wonder that farting, bloating and burping are relatively common.

Much of this gas production is recycled – by re-absorption and use within the , particularly by the almost two kilograms of bacteria in your colon. Indeed, almost 22.5 litres is absorbed by the gut, used by gut bacteria or expires through the lungs.

Passing what remains

The remaining two and a half litres is what you pass through your bowels every day. On average, men fart 12 times a day while women fart seven times – in portions of 30 to 120 millilitres. The total is the equivalent of a blown-up party balloon.

The number of times someone passes gas varies with the time of day; some pass more in the mornings and others more in the evening. But it largely depends on the sensitivity of the nervous system in the your . If you have an increased sensitivity, perhaps because of a condition such as , you may fart more often.

Most of the gas your body produces has no aroma, although about 40% of the population has the capacity to produce smelly hydrogen sulphide gas from the left side of the bowel because they carry a particular bacteria.

Smelly farts are of no great medical significance except in somebody with

Foods containing sulphur as a preservative, such as fruit juice, wine, processed meats and dried fruit also lead to more farting. These foods are used by the sulphur-producing bacteria in your guts to form hydrogen sulphide gas.

There are a variety of dietary ingredients that may increase farting as well as bloating, particularly high-fibre foods which ferment in the colon to produce gas.

One of these is fructose (a sugar contained in fruits), which leads to more because we don't have an enzyme to break it down. If consumed in large amounts, fructose can contribute to increased gas when it reaches the colon where it's fermented by bacteria.

This is particularly true of apples and pears, and their juice. Another culprit is stone fruit. When stone fruits are not quite ripe, they have higher pectin content, which is also fermented in the colon.

Then there are unripe bananas, which have a higher content of starch and less sugar than ripe ones. This passes to the colon as resistant starch producing more gas from . Orange pith can similarly contribute to excessive .

Often, as we age, the function of the pancreas gland, which is involved in digestion, slowly wanes and we can't handle fruits and vegetables we previously were able to eat with the same ease. The pancreas produces insulin to control blood sugar levels and these important enzymes are required to digest fat, protein and carbohydrates.

We should accept that farting is normal for the vast majority of people. If you feel your farting is a problem then you should look first to your diet before consulting a general practitioner about the potential for an underlying gastrointestinal problem.

add to favorites email to friend print save as pdf

Related Stories

Why does my stomach growl and make noises?

Oct 18, 2013

When people hear their stomachs make noise, most of what they hear is gas and intestinal motility, the normal movement of the intestines. Even when you're not eating, your gut is moving. If you have food in your intestine, ...

Bowel illnesses sometimes coincide in kids

Apr 21, 2014

(HealthDay)—Children suffering from irritable bowel syndrome are four times more likely than other kids to have a condition called celiac disease—an allergy to gluten—Italian researchers report.

Experts tell flatulent flyers: let rip

Feb 15, 2013

A group of medical specialists has provided an answer to a dilemma that has faced flyers since the Wright brothers took to the air in 1903—is it okay to fart mid-flight?

Recommended for you

Hospital staff say 'Crisis mode' obstructs communication

32 minutes ago

(HealthDay)—Staff members who perceive a work climate of crisis mode in their hospital units say that it leads to problems in exchanging patient information, according to research published online Dec. ...

Weigh-in once a week or you'll gain weight

1 hour ago

Stepping on the scale is common among dieters but how does the frequency of weigh-ins impact weight? A new study in PLOS ONE showed that the more frequently dieters weighed themselves the more weight they l ...

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.