No one likes headaches. Headaches suck.
Mechanically, though, I see Anna's point. Eating plants - taken as a whole activity - can do essentially four things:
1. Make you not hungry,
2. Relieve/treat illnesses or their symptoms,
3. Get you high/drunk, and
4. Get you sick/dead.
Garou regeneration takes care of 2, except in the case of Wyrm-poison/illness. 1 is mostly flavor, although having foods strongly spiritually associated with nourishment (corn in the Purelander tradition, wheat for European tribes, etc.) maybe act like lembas when Awakened is a cool idea. 3 is covered by the canon existence of Awakened peyote, and we can probably safely assume that's within the scope of what sanctified plants should do. Whether it should be "ZOMG trippin'" or "now it works on Garou normally" is up to ST discretion. 4 suggests that some pretty nasty stuff could be made from sanctified pokeweed or poison ivy, but it's nothing super-magical.
So, the question seems to be, are we okay with the possible effects of sanctification being solely things that plants are already capable of, but moreso? It contradicts canon in Anna's foxglove example, but "canon" is so weird and contradicted so frequently that I personally don't care about that as long as the rules/assumptions for this particular game are clear.