Beware of Flatus this Christmas
05 Dec 1993
Why would anyone spend time studying rectal flatus? After all, hell would have to freeze over before this research would win the Nobel Prize in Medicine. But it is rather refreshing, if you will pardon the pun, to learn that a researcher is investigating this malodorous human problem. So none of us should turn up our nose at this unique study. Or get careless at a Christmas party.
Dr. Albert Tangerman is a Dutch gastroenterologist at the University Hospital Nijmegen. He must also be a super salesman who could sell refrigerators to the Inuit!
Dr. Tangerman persuaded six adults to collect their flatus. I must admit I would have relished being a fly on the wall watching this experiment.
The subjects were asked to follow their regular diets. Then as they felt the need to pass flatus their task began. But I doubt that any of them said to friends, “Pardon me while I go and collect my flatus!”
How did they proceed? Dr. Tangerman provided each person with a 60 cc syringe. They were advised to press this tightly against the anus during the passage of gas. The syringe was then sealed securely for later examination by gas chromatology.
So what makes the odour? Tangerman detected four volatile sulphur compounds in the flatus emissions : hydrogen sulfide (H2S), methanethiol (MT), dimethylsulfide (DMS) and dimethyldisulfide (DMDS).
It’s been a popular assumption that H2S was the offensive ingredient of flatus. But this was found in only 75 per cent of emissions and DMDS in 25 per cent, while MT and DMS were present in all emissions.
Tangerman concluded that MT and DMS were responsible for the odour. Their threshold odour concentrations were well above the other gases.
But why does rectal flatus have such a penetrating odour? Tangerman says, “of all compounds known in the world, these smell most at the lowest concentrations.”
Now my apologies to my Greek friends. But Tangerman discovered another sulphur compound (propanethiol) after one subject consumed Greek food. Propanethiol has an extremely pungent and repulsive odour and may be due to the onions in the Greek food.
This research is hardly suitable for dinner table conversation. But just in case Trivial Pursuit enthusiasts are looking for interesting facts here are some additional particulars.
Flatus can reach mind-boggling amounts in patients who cannot metabolize lactose, the sugar present in cow’s milk. One man suffering from this condition deserves to be in the Guinness Book of World Records. He had 141 rectal emissions in four hours after drinking two quarts of milk! I fervently hope he wasn’t attending a dinner party.
Here’s another Trivial Pursuit fact you might fail. Rectal gas is potentially explosive. One patient was undergoing sigmoidoscopic examination for removal of a polyp in the large bowel. When the base of the polyp was cauterized to control bleeding the collection of gas in the bowel caused an explosion.
The result was a six inch tear in the patient’s intestine, the doctor was blown across the room and the patient’s head struck the table. The patient had ignored the doctor’s advice to take an enema before the procedure which would have reduced these gases to safer concentrations.
Suppose Trivial Pursuit were to ask, “Can holding on to flatus cause any harm to the bowel?” I never thought so until I read an article written by Dr. Wynne-Jones, a New Zealand physician.
Dr. Wynne-Jones claims we should all pass gas whenever necessary. He claims that holding onto flatus results in small herniations (diverticulosis) in the large bowel due to increased pressure. He may be right. But I assume he’s not a popular dinner guest in New Zealand.
So what can we do to decrease the chance of being the most uninvited person in town? Some old-fashioned advice is still sound. Avoid baked beans. They contain several sugars that can’t be broken down by enzymes. The result? Baked beans increase flatus 10 times the normal amount.
Corn, cauliflower, onions, brussel sprouts, cabbage and prune juice are also labelled as “flatogenic”. Don’t drink milk if you lack the enzyme needed to digest lactose. If that’s the case substitute yogurt which contains the enzyme.
A few years ago a computer search could not find one effective drug that would control flatus. That didn’t surprise me. Kings, queens and the rest of us have been unhappily passing flatus for centuries. It is a constant reminder of our common humanity.
One final tidbit for Trivial Pursuit. Never, never forget that some flatus is so powerful that it can be detected by smell in levels as low as one part in a million. A word to the wise! Practice restraint during this holiday season!
