Interesting you mentioned that, I also thought it was vit C because I always load up on C when I get a sore throat (which I got more often than my peers throughout my life).. But it's not C, I know because I got the flue/cold before and did not take any C, I still had that burping and upset stomach. The only thing that had a direct relationship to the gas and burping and seemingly inflammation all over is the cold/flue not any food or vitamin.
so, sore throat -> burping, upset stomach, gas, inflammation..