I tried a dried pear recently. Dried fruit has a lot of yeast in it, because the natural yeast inside the fruit multiplies a lot while it's drying. I can eat fresh pears so I figured this would be a good way to see how my yeast allergy affects me.
I got a painful bellyache in my upper abdomen, and I felt sick and out of it the next day. Not as badly out of it as my food intolerance reactions, and it wasn't the same kind of sick feeling.
In 2005, I was very sick for a couple of months while many of my food intolerances were emerging. And for about a week I had a terribly itchy rash on my legs. I tended it with cortisone cream as I lay there sick, until finally I looked at my food record and realized the rash had started right after I'd started using date sugar. I stopped using date sugar and the rash went away. I didn't check it with a date food challenge, because it's not worth it to me to risk getting an awful rash, but I think the hives were from my yeast allergy. Dates have a lot of yeast.
I haven't had this rash again, except very slightly now and then.
I've wondered if the yeast that grow in my intestines naturally could be irritating my intestines and causing problems like a "leaky gut" (i.e. high intestinal permeability). I obviously have had a leaky gut, since I have food intolerances, but I already have an explanation for it. I know I'm gluten intolerant, and that causes leaky gut. When people have "leaky gut" they develop food intolerances because food proteins get into the bloodstream and the body develops immune reactions to them. It's a vicious circle, because the food intolerances also cause intestinal permeability.
The amount of yeast in my upper intestines must be less than is in yeasty foods like dried fruit, because I have symptoms from dried fruit. Candida mostly lives in the large intestine. There's less and less the further you go up the GI tract, and very little in the stomach. I don't think the large intestine is so important for immune reactions. The large intestine absorbs smaller molecules like minerals, so (I think!) intestinal permeability refers to the small intestine.
The alternative medicine ideas about "Candida overgrowth" seem to be contradicted by medical research - people who eat diets high in refined carbs don't get more Candida, and people who think they have Candida overgrowth don't, at least not in their colons, which is probably where researchers measure it. But there's some intriguing evidence that Candida does have bad effects.