Irish Roots: John Grenham

Science, your mammy and the common cold


For decades, public health scientists have been assuring us that the common cold is caused by our spending half the year indoors sneezing on each other.

There’s no evidence, they’ve told us, that Ireland’s long- standing position as the world’s leading producer of winter phlegm has anything to do with the cold or the wet. “Old wives’ tales” they said, when we pointed out that for 10,000 years our mammies have been telling us that we’ll catch our death if we go out dressed like that.

And then last week came a complete change of heart. An article in the Proceedings of the National Academy of Sciences reported a recent study carried out by scientists at Yale (available via which shows that rhinoviruses, the culprits behind most colds and chest infections, thrive in cooler temperatures.

And the lower the temperature, the lower our innate immune response to viruses. And what’s more, our noses are usually three to four degrees colder than the rest of the body.

The scientists’ advice for avoiding runny noses? “Always stay in warm tropical weather or try to prevent the nasal cavity experiencing very cold air.”

Translate that into Irish terms and it says, “Either emigrate or dress the way your mother told you”. The moral is that not all evidence is full-blown scientific evidence.

Most research advice will tell you to treat your family traditions with deep scepticism and most professional researchers will say, “Yeah, right” (under their breath) when you tell them you’re descended from kings and princes.

But even though centuries of tradition may not constitute cast-iron proof, it remains genuine evidence. Discount it at your peril.

And the other moral is that your mammy might not be right absolutely always, but the odds in her favour are pretty good.