Re: Gluten sensitivity
If you think modern (or Chorleywood) process produces bad bread, look at some of the adulterants the mid-Victorians put into the bread:
Chalk (for whitening)
Alum (again for whitening) - some said this caused ricketts as it could prevent the digestive system from pulling nutrients from other foods consumed
Arsenic - by accident made it's way into some loaves. The baker claims he was adding Alum but mixed up the containers
Millers routinely put "rotten" or sour flour into the mix to sell off gone-off stocks with no one noticing
Bone meal (whitening again)
Whatever the brewers had adulterated the yeast with - beer brewing created yeast, which the bakers purchased as there was no such thing as dried yeast at that time. Brewers adulterated beer too, and that made it's way into the yeast.
Potatoes
Plaster of Paris
Sawdust