I don't think wheat is necessarily the root cause of this problem, but I can tell you that not eating wheat or any wheat relatives with gluten (which is a monumental task...you'd be surprised where traces of wheat hide, even as fillers in spices & medicines) has taken care of some of my weird issues, I think. I know for sure that it took care of my depressive crazy episodes (ones where I thought I would give up living) and anxiety. I would wake up with anxiety. I haven't had racing heart beat upon waking (usually coincided with anxiety) for a long time now, and I suspect that eliminating gluten helped with that. I haven't had any asthma or allergic reaction episodes aside from sneezing associated with pollen (and even that is mild).
Even a sip of beer will set me off into dark miserable thoughts sometime in the next 24 hours or so. The longer I've been "off gluten," the more sensitive I am if I have a little. I'm also more observant of my body than I used to be, though.
The rapid heartbeat thing I've had was so worrisome to me, I ended up doing a stress test at a cardiologist's to rule out heart defects. I'm 31 - I was probably the youngest patient there :) My heart is normal according to the cardiologist.
Then again, I supplement with iodine and other nutrients, which also could have had an impact on these issues.