Re: Rotten egg burps, gassy...
I am 27 and have suffered from this off and on (bloating, sulfur burps, etc) since I was 18. A naturopath doctor in Tucson told me to avoid eating a naturally occurring chemical in foods called Malvin. This is a natural red pigment and is in almost all reddish-colored foods plus some others--- so i avoid tomatoes, berries, beets, chicken, chili powder, eggplant, etc. Malvin is a type of phenolic compound and for whatever reason, it appears my body can not process phenolic compounds well, especially Malvin and Tannins. They are normally harmless for people---but not for me. My own research indicated that this has to do with a low ability to process sulfur, or phenol-sulfur transferase deficiency. In the body, sulfur you eat usually gets turned into sulfates. Sulfates do lots of important jobs like detox phenols through the liver, regulate neurotransmitters, help re-grow cartilage. Phenol-sulfur transferase deficiency can cause autistic spectrum disorders as well.
When I start to have an episode with sulfur burps or gas---I eat only brown rice for a day or two to detox from the phenols, then avoid Malvin as best I can until I am symptom free. This means avoiding LOTS of foods but it seems to work.