Filling in the FOS Blanks

From my earlier musings around why probiotics made me all migrainey and sick feeling? um, a moment’s worth of research on the ingredient FOS reveals:

FOS = Fructooligosaccharide

In other words, “The term oligosaccharide refers to a short chain of sugar molecules (in the case of FOS, fructose molecules).”

So, while I don’t totally understand all these words (four years worth of Biblical Hebrew is not coming in handy here at all), I’m gonna take a beginner’s guess and say that I think my problem with both FOS and HFCS is the fructose part.

Anyone with any kind of biochemical or biology type knowledge want to weigh in here? What’s going on with the fructose in both these things? Why would they both have neurological ties?

There’s an answer in here somewhere, but I just can’t put together the pieces yet.