I would rely on the advice of my urologist. If you are having problems, please discuss these with them.
To my knowledge, there are no diets or supplements that have any effect such as those you mention. Remember that the ads and the hype are ADVERTISING and are meant to entice purchases. Many studies have shown that these supplements, which have no government medical supervision, often do not even contain what they claim to and can be harmful.
You are just barely finished with the first 6 BCG treatments and the urgency and other symptoms that you feel are quite normal at this stage. Your urologist can prescribe one of several drugs that can help. And things will improve as your bladder heals.
A normal, healthy diet and lots of fluids are usually the only "magic" that we need.
Diagnosis 2-08 Small papillary TCC; CIS
BCG; BCG maintenance
Vice-President, American Bladder Cancer Society