What Causes Relief In Stomach Bloating After Taking Galactosidase Enzyme ?

I have been suffering with sever bloating for 11 years. I get so boated, I actually pass-out from the bloating and am unconscious for an hour or two. Two weeks ago I picked up a bottle of Gas X Prevention - which is mostly just A- galactosidase enzyme. I have experimented with many of the food situations that have cause me grief. If I take this pill when I begin to eat, I can eat almost anything (with minimal gas but no bloating). My question is this ----- What is going on inside of my body that makes this pill work so fantastically? I mean, Is my body supposed to be producing this AG enzyme and doesn t. If so Is there something that can be done to revive this function in me (‘cause at $6.99 for 20 pills. I ll be spending $1,000 a year on these piills.) . I get this enzyme from the pharmacist so my insurance would pay for it? By the way I also have parkinson s (diagnosed in 2004), which every doctor I ve gone to has said that that is whats causing my bloating (the parkinson s)                          Mike W