this person mentioned that his parotids swell when he eats. one theory is that his salivary glands are straining to produce saliva and hence the parotids are suffering.
however there is another possible explanation.
the parotids are located very close to the tonsils which come in direct contact with food allergens when someone is eating. when the tonsils react, so do the parotids, only for some reason the parotids react much worse.
now many food allergies haven't been made mainstream knowledge or conclusively proven to exist - but anecdotally, people have reported parotid swelling after eating foods with whey in them (a protein found in cows milk). and whey is in almost everything processed. it's in milk, cheese, cream, butter, crisco, many other vegetable shortenings, chocolate, ice cream, cake, yogart, etc.
for someone with parotid swelling, a completely non-dairy/whey diet can majorly improve the situation. the problem is that to totally avoid whey, one has to pretty much give up dining out. and many food products contain whey even when they don't list it as an ingredient. so the only real way to avoid whey enough to see improvements on parotid swelling is to prepare your own food. and to eat simple foods whose origins you can be certain about: eggs, meat, poultry, potatoes, vegetables, fruits, etc. most pasta doesn't have whey in it, but many pasta sauces do: vodka sauce for example.
of course avoiding all food allergies is the thing to do, but many people have this whey sensitivity and aren't even aware of it, and since whey is so prevalent in today's foods, to eliminate it is both a huge undertaking and a huge benefit.
one of the reasons whey sensitivity is so under the radar is that dairy allergy usually gets attributed to lactose intolerance which is something completely different. but people assume that if they take a lactaid pill, dairy becomes healthy for them. this is not the case if the person has an actual sensitivity to the whey protein in the dairy.
anyway, i hope the person who wrote to you gets to read this, because eliminating whey has saved me from my parotid swelling. sometimes whey slips into my diet here or there and my parotids swell right back up. so i've truly seen the cause and effect in my own experience. but for the most part, it's been a huge success for me.
Thank you for sharing your comments. KH