“It was like a cloud had lifted, and she could think more rationally again.”  That’s how one mother described her teenage daughter — a sufferer of “erratic mood swings” — after eight weeks on a high-dose regimen of dietary supplements.  In teenagehood, some degree of irritability comes with the territory. But a clinical trial out of New Zealand shows that severe emotional disorders in teens could be exacerbated by something as seemingly innocuous as a gap in their diet. The study was led by