Excess Gas and Flatulence

The average healthy person will pass gas about ten to fourteen times per day, producing an average of half a liter of gas – though some people can produce a liter or more if they consume certain foods.

When malabsorption (reduced food absorption) occurs due to certain medical conditions, excess gas in the intestines and excessive flatulence (farting) could be a symptom of these disorders:

  • diverticulosis that leads to an overgrowth of bacteria
  • celiac sprue
  • pancreatic disease
  • short bowel syndrome (where part of the bowel was removed by surgery).

Gas is caused by fiber, starch, and some complex sugars which aren’t easily digested and pass through to the colon where they are fermented by bacteria which produces hydrogen, methane, and hydrogen sulphide gases. Yeast tend to produce odorless carbon dioxide gas, but the farts can pick up odors from rotting vegetable material and putrefying meat stuck to the walls of the colon (mucoid plaque).

The foul smell of flatus comes from various sulphur-containing compounds. The compounds in a typical smelly fart are usually hydrogen sulphide or methanethiol. The “rotten eggs” smell comes from hydrogen sulphide gas, and a “rotting vegetables” smell comes from methanethiol. Yet another sulphur compound, dimethyl sulphide, actually smells kind of “sweet”.

Cauliflower, eggs, and meat are most likely to produce the smelliest farts. Beans produce a greater quantity of gas, but not particularly smelly farts. In general, foods with little fiber produce very little gas.

Giardiasis, an infection by the Giardia protozoa parasite, can produce the most nauseating farts and belches, along with extremely foul-smelling watery diarrhea.

Another cause of excess gas can be a lack of the enzyme lactase which is needed to digest a simple sugar called lactose or “milk sugar”. In a person who lacks this enzyme, consuming milk and dairy products which contain lactose can leave the dairy foods poorly digested and not absorbed by the small intestine. As it moves through the large intestine it becomes food for yeast and putrefactive bacteria – organisms which produce gases like carbon dioxide, hydrogen sulphide, or methane. When there is a yeast overgrowth in the colon, even more gas is produced.

People who cannot digest lactose are said to suffer from lactose intolerance. An hour or two after consuming milk or dairy products they can experience uncomfortable cramps and excess gas in the abdomen. This problem is compounded when the use of antibiotics kills the probiotic Lactobacteria which help digest lactose for us.

While cheese, milk, ice cream and frozen yogurt can cause the cramping, regular yogurt does not, because the live bacteria culture which fermented milk into yogurt breaks down the lactose so we can digest it.

Some foods which are considered “high flatulogenic foods” (the suffix genic means “creating” or “causing”) are the ones most likely to cause excess gas in the small and large intestine, an uncomfortable or painful “gassy” feeling in the abdomen, and excessive flatus or farting:

  • milk, cheese, ice cream, frozen yogurt (not regular yogurt)
  • most beans, such as baked beans, lima beans, pinto beans, navy beans, soy beans
  • sauerkraut, cabbage, cauliflower, broccoli, brussel sprouts, asparagus, radishes
  • prunes, onions, carrots, raisins, bananas
  • bagels, pretzels, wheat germ.

Foods which are moderately flatulogenic include:

  • foods that contain wheat and wheat products, such as cereals, breads, pastries
  • potatoes, citrus fruits
  • carbonated beverages, sodas.