I know this sounds simple but it's worth a try and not expensive or difficult. I had a similar issue and I did a lot of research to solve the problem. One thing I discovered is that volatile sulfur compounds (VSC) that make the breath smell bad can be bound by divalent cations through their interaction with sulfur. When the VSC are bound by divalent cations they precipitate and are removed from the body in the urine. Divalent cations are minerals like calcium, magnesium and zinc. My problem started when I began jogging. It struck me that my bones might have constituted a strong drain on my intake of divalent cations as a result of the bone building that must accompany the impact on the bones from running. Bones have a high concentration of divalent cations. I tried taking a calcium, magnesium, zinc supplement 3x a day with vitamin D to help absorb the minerals and I think this helped a lot. I also cut way down on sugary foods, dairy and meat as these foods seem to exacerbate it. As I said, these minerals are cheap and worth a try. I hope this helps.