Alternatively, the Type IIs may have a process at work which is designed to rid the body of excess levels of thiamin.
If, for example, the normal diet were reindeer or similar game for a couple of hundred thousand years, with side orders of seal, when available, or salmon in season, and hold the veggies, you could have an adapted population that would be swimming in thiamin.
So, is there some toxic level of thiamin we should know about?
http://lpi.oregonstate.edu/infocenter/vitamins/thiamin/
The B complex plus C is widely available in “Stress tab or Stress vitamin” formulations. These have levels of up to 1000% the MDR for these compounds.
I take a routine “over the counter” B complex tab each day in addition to the morning multivitamin. I’d be careful about too much niacin, though, as it can cause problems in ultra-high doses. That is why I avoid Stress tab formulations.
The old saw from biochem is that it is the “fat solubles” that can get you into trouble including A, D and E. If you want an antioxidant instead of E, might be better to go to alpha-lipoic acid which has shown some interesting results in stopping free radical formation.