I've been suffering from these blasted things for 18 years, and have similarly noted the same sorts of correlations. My best efforts: cutting out gum; cutting out sharp foods; cutting out acidic foods; taking vitamins B-12 and C, L-lysine, and zinc; switching toothpastes and brushing techniques. I regret not recording my history of occurrences, but I perceive things are improving. At the very least, it's safe to say the cause of canker sores is multi-factorial.

Sorry, I'm rambling. No one in my life can relate, so I'll take any chance to talk about it.

I've noticed the same causes and correlation. Canker sores' formal name is aphthous stomatitis. But whether it is an autoimmune disease is debatable. As noted in [1]:

"Despite this preferred theory of immuno-dysregulation held by most researchers,[7] aphthous stomatitis behaves dissimilarly to autoimmune diseases in many regards. "

[1]: http://en.wikipedia.org/wiki/Aphthous_stomatitis

Or lichen planus.

http://en.wikipedia.org/wiki/Lichen_planus#Oral_lichen_planu...