I frequently eat onions and cabbage...and I use stevia that contains inulin...which is the derived from sun chokes. I also occasionally drink lassi...watered down plain yogurt with cinnamon, vanilla, black pepper and stevia...YUMMY!...and I also take probiotics. So who knows what is doing what...but it works for me!
I will say that I have noticed an increase in phlegm since I started using more dairy...heavy cream, yogurt and cheese...and will be experimenting soon to see if this will decrease by cutting out the dairy altogether. I will definitely miss my lassi and cheese : ( ...but I hate being snotty!
I agree with Gray about most probiotics...they need to be human strain, viable and stored properly in order to be effective.
All that being said about dairy, though...I am very curious about kefir and just might get some grains.