Flatulence

On a par with bloating, this is one of the major recurring symptoms of which food and other allergics complain. Bloating is caused by gas in the intestine, mainly the colon. I have seen patients during challenge tests enlarge in a matter of one or two minutes, putting on as much as 6 in/15 cm. If the gas becomes excessive, flatulence results (farting, blowing off). It can come and go very dramatically.

There is no comprehensive physiological explanation as to where the gas comes from or, if not expelled, where it goes. Perhaps it is reabsorbed – but this seems a bit unlikely in view of the obvious volume involved. One of medicine’s great mysteries, but not one likely to attract a would-be Nobel prize-winner!

The fact is, any allergy can cause it but certain groups of foods are particularly associated with flatus: the pulses are notorious for it (beans and wind often being the subject of crude jokes); brassicas are not as widely recognized but are just as much trouble. Remember, it is not necessarily every member of a food family that causes a reaction.

Gluten enteropathy has long been associated with bloating, flatulence and bulky, stinking stools-indeed, these are important diagnostic signs. Lactose intolerance and true milk allergy can lead to bloating with dairy products. Lastly, the yeast syndrome, or intestinal fermentation, causes much flatulence.

The truth is any food allergy or intolerance can do it, it's merely that these are the common offenders.