I'm not sure when gluten was invented, but I do know that a generation ago hardly anyone had heard of it. If you asked someone about their reaction to gluten they would have been most likely to say they weren't sure, but it sounded delicious and could they have an extra helping, please.
Now, cafe sandwich boards on footpaths tempt with the promise of gluten-free goodies within, magazine recipe features are devoted to the preparation of gluten-free meals and otherwise sane supermarkets give over whole sections to gluten-free baking, small goods and possibly children's wear.
But what does gluten intolerance really mean? In most cases it means wheat makes you fart. Something analogous happened with the common cold a few decades ago. It almost disappeared, but not because someone had finally found a cure. Instead, colds were redefined. Gradually, people with a runny nose, sore throat and a temperature had come down not with a cold, but "terrible flu".
The very name "common cold" told you its days were numbered. Why would you suffer from something as mundane as a cold when you could have something as flash as flu.
We appear also to be in the middle of a plague of that sinister-sounding complaint, irritable bowel syndrome. This used to be known as the squirts and generally resulted from stress and bad food.