Those candida toxins reside within the body and if your organs cannot cope with the after effects, than the toxins will stick around.
For instance, your lungs are the “dumping grounds” of the body, so if it caused die off, the toxins likely flooded her lungs. It can flood the liver and kidneys as well with toxins…thats why we recommend molybdenum.
I would test other foods seperately for leaky gut and if you can put together a list of foods she is allergic to, than you can determine it at that point. For instance, if she reacts to sugar, grains, molds, etc…that is leaky gut. IF she just feels bad after kefir, than that is not leaky gut.