St. John's Wort Side Effects

Have you ever encountered St. John's Wort interacting to cause mineral depletion?

No, I have not heard of any such effect. In clinical studies quoted by Steven Bratman, M.D. in his book "Beat Depression with St. John's Wort" (Prima Publishing) only 2 to 4% of patients experience minor side effects. The most common side effects in one study of 3,250 patients were mild stomach discomfort in 0.6% of patients taking the herb, allergic skin reactions in 0.5%, tiredness in 0.4%, restlessness in 0.3%.