Why Beans Give You Gas

The Beaneater, by Annibale Caracci

Today I found out why beans give you gas.

Beans contain a sugar molecule called ‘Oligosaccharides’. These types of sugars cannot be digested by the stomach or small intestine. They get passed on to the large intestine where numerous types of bacteria begin to break them down. During the process, the bacteria release several different types of gases, mainly hydrogen, nitrogen and carbon dioxide. Don’t be concerned about these particular gases, they are stench-free!  Your fetid flatulence affliction is from a different source.

About 1/3 of the microbes end up producing methane as a result of breaking down these sugars. Once the methane builds up to the point that it begins to produce pressure on your anal sphincter…. BAM!!! A release that allows kids everywhere to play the infamous “Door-knob, Safety” game.

When you eat any food, your body has to process it. You can think of your digestive tract, that path between your mouth and your anus, as a system that is essentially outside of your body, just contained within it. It’s the job of your digestive system to break down the foods we take in, allowing the nutrients to “cross-over” into the different body systems and organs for use as fuel. Each different part breaks these foods down differently. For example, the mouth chews it up into smaller parts, the stomach uses enzymes and acids to further break it down. The food then goes to the small intestine where most of the nutrients that come from our food (proteins, fats, and carbohydrates) get absorbed into the bloodstream by a process called diffusion. What is left over is then passed to the large intestine whose main job is the absorption of water that remains in the indigestible residue of food. A smaller role of the large intestine is also to break down polysaccharides (fiber) that gets passed into it. One type of fiber is the aforementioned Oligosaccharides.

Oligosaccharides are basically sugar molecules that are made up of several different types of monosaccarides (usually 2-10) to form a polymer. An enzyme that would break these molecules down does not exist anywhere inside the human body. Therefore, when they passed into the large intestine, they serve as food for the countless microbes present. This is important for our health as these bacteria are necessary for creating different vitamins that get absorbed into the body as well as for the production of antibodies that help fight off certain types of infections. The downside is that the gaseous side effect of these bacterial processes tends to clear rooms everywhere.

You might have resigned yourself to the fact you can never eat beans before going on a first date, but fret not! There are some methods to prevent your noxious abdominal expulsions. For instance, there is a type of mold called Aspergillus niger that contains an enzyme (Alpha-Galactosidase) that will break down Oligosaccharides, preventing your large intestinal bacteria from creating gas. You can buy it at stores everywhere under the auspicious name “Beano“. If you don’t want to be seen sprinkling your beans with this product, you can always try soaking your beans in water for several hours before you make your food. This softens the beans and allows them to ferment. The yeast produced can consume the offending Oligosaccharides and help leave your dinner date vapor-free!

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Bonus Facts:

  • A typical human gut contains around 100 trillion microbial cells (click the link to learn more).  This means there are about ten times more bacterial cells in you than there are cells of you… creepy…
  • Everyone will react differently to certain foods, and some will cause gas in one person and not the next. However, there are some common foods that can cause gas (other than beans). These include: the artificial sweeteners Mannitol and Sorbitol; dairy products like cream, ice cream, and milk products; fruits like apples, avocados, bananas, melons, prunes and raisins; vegetables like broccoli, cabbage, corn, green peppers, cauliflower, onions and Sauerkraut; high fatty foods like meats, gravy, and fried foods; and grains, starches and products with high wheat content.
  • Ever heard of a poop transplant? If you think that having all that fart producing bacteria in your gut might not be that awesome, think twice. A type of bowel infection that comes from a bad type of bacteria known as Clostridium difficile can cause symptoms ranging from uncontrollable diarrhea, colon inflammation, and blood poisoning. Patients that have recurring episodes of this type of infection are often low on certain types of other bacteria (known as flora) that can fight off this infection. When this situation occurs, doctors yield to Mother Nature and go after readily available stores of the much needed flora. How do they do this? By transplanting it from the colons of healthy people. Specially by taking a healthy person’s fecal matter, diluting it with water, and then putting it into the colon of the patient. A bona fide poop transplant, that can actually save lives, and will probably cost you a crap-load (eh-eh?) of money to have performed, at least if you live in the United States!
  • A study done in 2009 showed that 13 out of every 1,000 hospital patients are infected with C. difficile.
  • If you think a poop transplant is gross, just know that an enema is not the only way doctors can get healthy flora into a patient. They can also feed it to them (yum?) or put it in their nose. However you receive the flora, once in the patient, the healthy person’s flora begin to propagate and attack the Clostridium difficile infection. The cure rate with this treatment is approximately 90%.
  • In April of 2012, a 66 year old man from Albert Bridge, Nova Scotia performed the infamous fecal bacteriotherapy on himself. He had reached his breaking point, living with C. defficile that he contracted from a routine surgery 18 months previous. His doctor was supposed to perform the procedure one month earlier. However, a problem arose when the hospital approved the procedure without setting any guidelines for it, so the doctor postponed the transplant. So feeling very “MacGyver-like” he took feces that belonged to his cousin and mixed it with some water and shoved it up his rectum himself, for free!
  • The average length of the small intestine is 22 feet 6 inches in men, and 23 feet 4 inches in women. These averages are somewhat misleading as the actual length can vary from about 15 feet to as long as 32 feet, depending on the person. The average length of the large intestine is 4 feet 9 inches.
  • The “Door-knob, Safety” game is played as follows: Should a person produce any sort of flatulence, that person must claim the offending sound and or odor by shouting out “safety!” Should a person nearby the offender hear or smell the broken wind and yell out “Door-knob!” before the windbreaker says “safety” the person yelling “door-knob” is allowed to hit the farter as hard and as many times as they want. The beating must cease as soon as the other person touches a door knob. In the case of a tie, the claim of “door-knob” will be honored and hitting can commence. This is because the person who has the right to claim “safety”, should have known in advance that they were about to cut the cheese.

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  • Today i found out that there is a purportedly infamous “Door-knob, Safety” game which i’ve never heard of.

    • A Disgruntled Brit

      Summary, at least how I know it (these sort of games differ wildly between regions I’ve found);

      When someone passes gas (here on known as the farter), they have to say Safety. If someone else (the fartee) says Doorknob before the farter says Safety, everyone in the room is allowed to punch the farter in the arm. The amount of times differed between my friends, some said once, some said as many times in a row as you want.

      (Obviously I would like to add I do not play this game any more)

  • My boys play the door knob safety game ALL the time. One day they were staying with my best friend. They were all laying in bed watching cartoons. My friend heard my youngest say “safety” and giggle. She thought saying “safety” was something taught to him by me when someone was invading his personal space so she moved over. About 20 minutes later he said it again. She started to feel bad because she thought she was making him uncomfortable. Finally, after saying it a third time she asked him why he kept saying “safety”. When she found out it was a fart game she was relieved and dumb founded at the same time. I thought it was pretty dern funny. I got a good laugh out of it when she told me! 🙂

  • Beans don’t make people fart. I know hundreds of people who eat beans almost everyday, sometimes more than one time a day, and no one ever complains about beans and gas. I only hear USA citizens do that. Maybe USA people never really eat beans and only read articles like this one so they assume what they read is true. I never hear of any reports on Mexican TV talking about gas from beans. Beans have been eaten in Mexico for thousands of year, no bean gas story from the Mayan or Mexica. Mexica is the real name of the Aztecs. The work Aztec is a fake made-up name, some German came up with that name.

    • A Disgruntled Brit

      I (as you can probably tell from my name) am from Great Britain, and I can safely say that any day where I have eaten beans the day before, my backside makes it rather unpleasant for anyone else in the room with me.

    • As a Mexican-American where beans were a staple in almost every meal, I can say that I never heard of the gas thing until I heard it on TV.

    • I’ve read that it is directly related to how frequently you eat beans. The classic American diet is low on fibre, so if you suddenly eat a meal with a lot of fibre and your body isn’t used to it, it doesn’t handle it very well and digests it too slowly, so you end up with gas. If, however, you eat beans every day, your body adapts and you don’t have the gas problem.

      My husband and I eat beans everyday and although we do have some gas, it’s not on the level that people usually complain about around here when they eat them. My gas really isn’t that bad (and when you consider that there are a number of foods that can potentially cause gas, the beans wouldn’t be the only contributors). My husband’s is worse, but he has serious digestive issues and not eating beans wouldn’t stop the gas.

      So, yeah. It’s not that beans don’t cause gas at all, but rather than the frequency with which you eat beans and other high-fibre foods affects how well you digest them.

  • In my family, when someone farts, he/she says that he/she smelled recently made bread and anyone around would take a deep breath (through the nose, obviously)… I guess you can infere the end result.

  • I can honestly say I have never heard of this game called door knob. Wow you learn something new every day.

  • I hardly eat beans bcos of gas, it makes me fart like hell.

  • beans the magic fruit
    the more ya eat
    the more ya toot
    the more ya toot
    the better ya feel
    beans, beans for every meal