Hi -
Here is a link to Sloan-Ketterings web site for Herbs and Supplements. It is managed by their Integrative Medicine Services staff. I have found it to be very helpful.
http://www.mskcc.org/mskcc/html/11570.cfm
You are still on chemotherapy, so it is good to take vitamins in moderation, but we do need our minerals and B vitamins. Also Folic Acid.
I read that a person would have to drink about 8 cups of green tea per day to get a good anti-cancer benefit. I stick mainly to other types of herbal and "detox" type teas to cleanse my blood. This helps with my energy level.
Many of us on this board have made dietary changes - the most important is to cut way down on the sugar and junk foods with "empty" calories. Good nutrition is very important for building yourself back up after a round of chemotherapy.