Actually, I've read that many (but not all, apparently) lactobacilli type probiotics and bifido type probiotics produce acid. I was reading a lot about these a year ago, including which of them added to sterile milk will produce yogurt - they consume the lactose in the milk and produce acid, changing the milk into a tart yogurt.
Lactobacillus acidophilus, for example, is called "acidophilus" because in Latin that means "acid loving".
I wish I'd kept the links, but I didn't.
Ooops. Of course! Feeling silly.
Thank you all.
Though perhaps there is something specific that B Longum does. I guess inevitably the only way to tell is to try some.
I have got some of Natren's B Infantis and B Bifidium. The first time I took a tiny bit of B Infantis I got waves of nausea and discomfort. After it subsided I felt really good. Happy and a bit zoned out. B Infantis was the first probiotic I tried in this whole RS experiment. Vegas recommended it, it is particularly good for infants, along with L Reuteri, which I also have. It seemed to make sense at the time to start with those.
I empathize with everyone, I have similarly felt horrible at every single stage of this. Every time I introduced a new probiotic - ugh! The sheer level of discomfort has been unreal.
Best wishes to all!